bi-monthly interface with the construction industry in ethiopia
Cement
Crisis of a strategic binder
4
2006
www.constructionahead.com
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From the editor Letting lose runners of the economy
W
e have already underlined the inherent link between construction and development by saying the latter is inconceivable without the former. No construction, no development. And for us who are moving away from timber and yet nowhere near to steel as the mainstay of building, no cement means no construction. Hence, the shortage as well as the high cost of cement amounts to a clamp on development. But why has such a serious situation come about with regard to the supply of cement? Specially when we are told that the seemingly omnipresent construction activity we see is not really that substantive, transformative or insfrastructural. The Ethiopian private sector has been repeatedly accused of being parasitic (tigegna). Now it is easy to dismiss this as one way of expressing the usual unfortunate antagonism that exists between business and government in every society. But before we do that, we should look into the charge from many angles and from different perspectives. Where from, for example, does the accusation rise? What is the main reason for it? The issue is indeed debatable and would enlist many proponents on both sides, taking various positions or views. We believe that the charge is intended mainly to convey the idea that the sector is not productive in its main thrust, impact on the economy and focus of activity, that it is not contributory to wealth creation, that it does not create opportunities for employment nor advance the enterprising spirit and endeavour so as to serve as the engine of socioeconomic progress, which it must, that it merely lives off what has already been produced by simply extending the chain of retailers and recyclers. No value adding in other words! Hence it simply exploits the demand side (consumers) of the economy with what is there and without putting anything of its own on the supply side. But so long as money is the sole measure of success and pecuniary interest remains the driving motive, who is to fault the practice; and don’t people have the right to pursue what they want and how they go about obtaining it? Seeing what is going under service, commission agency or dilela (the Amharic word has the connotation of appeasing even with a lie), street children or the unemployed now want to make you pay for showing you the way or for pointing to an address. But what has all this to do with construction? Nothing, if it were not for the questions of meritorious entrepreneurship and the cost of cement in Ethiopia, which has taken center stage in this issue of Construction Ahead. In short, we want to add our voice in welcoming the good news that so many have taken investment licences to produce cement. May this development serve as an inspiration, impetus and a confidence building one for others to go into more productive enterprising, not just in the construction sector but in all the vital sectors of our economic life.
Construction Ahead, mar-apr 2006
Bi-monthly interface with the Construction Industry Tel 515 24 77, 515 24 47 P.O.Box 81062 Addis Abeba, Ethiopia mail@constructionahead.com www.constructionahead.com
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Editor in chief
Benedino Ferraresi
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Tigist Woldemikael
Research team Contributors
Layout Design Printing Advertising design
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Suggestions and contributions are most welcome and can be mailed to : Construction ahead P.O.Box 81062 Addis Ababa, Ethiopia or posted using: www.constructionahead.com or e-mailed to: mail@constructionahead.com No part of this magazine may be reproduced or duplicated in any form without the written permission of the publisher. All rights reserved. Articles, Photos and Drawings sent by customers, are not returnable even if not published.
Views expressed in Opinions Column belong to authors and do not represent the views of the publisher.
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letters Dear Editor, I read the article ‘Professional life in a design studio’ with mixed interest. I have heard the author express his views on related issues a number of times. My re-collection was that CM was primarily concerned with the post-design phase. His article disregards the accepted project delivery systems, including those that clearly define the role of the CM. The policy of the International Union of Architects in this regard is quite clear. The member associations including the AEA prescribe to the policy of the UIA, and find nothing detrimental in fostering teamwork by accepting the traditional role of the architect in leading the design team. Zerai Mesfin may have had one more issue to be furious at if he had read this article. I would wait and see how the series of essays on the subject develops and how it addresses the role of the architect before responding to the author’s view point in detail. Wouhib Kebede, Architect AEA Furious or not, we too would like to hear architect what Zerai Mesfin (Construction Ahead No. 3,Jan-Feb 2006) or other architect have to say about the question you raise. However none of them would take issue, we are sure, with what was said about the value of teamwork in the article. Coordination and teamwork are glaringly lacking in our Ethiopian context, in construction no less in our footballing… In any case, we appreciate and thank you for your interest and let’s hope that others will be forthcoming with their views on this and related vital issues. Thank you for your letters. We want to make this magazine one that answers your questions, caters to your needs and helps you accomplish your job more efficiently and prosper in your business. Please let us know what you like and what you don’t about our magazine and what you like to see more of. Letters to the editor should be sent by e-mail to letters@constructionahead.com or mailed to Construction Ahead P.O.Box 81062 Addis Ababa, Ethiopia.
2006
30
Cover Story
The grey powder Crisis of a strategic binder
Regulars 27
perspective Less Value to time Less Success Professional life on the construction site: focus on time planning
38
48
interview
The welcome conqueror under question
opinion
Ethiopia well covered
The Mexican Wave I once heard someone say - If you are going to make mistakes, at least make new ones
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18
The shady reputation of a grass root’s success
EUCALYPTUS
product advertising POLYCOAT Thixotropic cold applied non-ionic bitumen emulsion
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Features
Ing. Alberto Varnero Ing. Alberto Varnero, kindly answers to Construction Ahead about the building construction business in Ethiopia
technology Living Envelope The UFO has landed” - this was the headline used by some newspapers on the day of the opening of the Allianz Arena
Reviews 56 software review Bricks and clicks Building may become even higher-tech, with projects ‘finishing’ on-screen before construction starts e-COL A concrete column design software package capable of designing concrete columns
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books
62
snapshot
24
In 1967, neither the established offices nor the government ministries were ready to absorb the small number of graduates. Although by 1972 the total number of graduates didn’t exceed forty, employment opportunities were extremely bleak.
CONSULTANCY SERVICES IN ETHIOPIA
42 The Dagu Bridge, an innovative yet cost‑effective tied-arch structure in Tianjin, China
Sun Moon and Stars
Issue No. 4
Departments 4 from the editor 7 letters 10 news 14 world news
news
More Companies Eyeing Cement
I
n the past just one year, about seven local and international companies have taken licenses from the national and regional investment commissions to embark on cement manufacturing. The investment, according to experts, may have been driven by the unfilled demand and supply gap that has affected the construction industry especially during the past three years. Even though the per capita
demand of cement in Ethiopia is only 20 kg, much lower than even neighbouring countries, this demand remains unmatched by supply. The three factories producing cement presently Muger, Mesebo and Dire Dawa have an annual production of 1.6 million tons. This shortfall of the high and still growing demand that is estimated nearly double the produced amount. According to data collected from the Ethiopian Investment Agency, the first non-government entrant cement production was the Messebo factory registered in 1993 to operate in Mekele, Tigray. Garad Plc in 1997 and Ture Plc in 2002 the next private companies to take investment licences for cement production. These were followed by Libo Sisay joint investment in November 2004 until the sudden boom in cement production investment in 2005. However, according to production manager Ayele Yigi, the company is now preoccupied with its latest steel mill project worth ETB 350 million that is to be operational in July – August 2006. The company is also engaged in seven other projects including brick and PVC manufacturing. “Though we perceived the coming price increase in cement we had to focus on our
primary long-term program which was steel converting plant”, said Ayele. In 2005, seven more companies took investment licenses from the national agency bringing the gross investment capital allocated for new cement factories to more than 11 billion Birr. After conceding its plot for establishing a factory at Derba to the latest giant Derba Midroc, Rena International Investment Plc is expecting to find another limestone quarry in the Oromiya Regional State. With such growing initiatives cement plant congestion is being seen in some known site of limestone deposits. Another May 2005 applicant, Ethio‑Korean Development, was close to acquiring a land at Melka Jebdu in Dire Dawa regional council before National Cement Sc. (the former Dire Dawa cement) meddled in
Last year, the second annual WORLD OF
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was
another big success, with thousands of construction professionals from all over the world gathering in Mexico City to do business. World of Concrete Mexico 2006 will once again take place at the state-of-the-art Centro Banamex in Mexico City. From June 14 -16, 2006, highlighting the best technologies in machinery, equipment, commercial construction products and services from leading industry suppliers.
the process and requested the plot for its expansion project, according to Emir Abdulah manager of Ethio‑Korean Development. Subsequently the two companies tried to come to an agreement to establish a plant together but with no result. “We were not sure about their capacity therefore we were reluctant to proceed with the arrangement”, said Emir. However Ethio Korean is looking for another limestone deposit in collaboration with the regional government and the Federal Ministry of Mining and Energy. Ethio‑Korean has allocated ETB 180 million for the Portland cement plant that is expected to produce 1.5 tons of cement per annum. National Cement Sc. was established after East Africa Ethiopia Group acquired 80% of the former Dire Dawa Cement in partnership with the British JMP in November 2005 to enhance its production capacity by 10,000 tons from the 25,000 tons annual production it had until last year. Ethio-cement Plc, a private subsidiary of Eneyi General Business Plc, is planning to construct a cement factory at a project cost of 60 million Birr, on 53.8 hectares of land it already acquired last year in Northern Shoa, in the Chancho area, 40 km north of Addis, in the Oromia Regional State. Another company, Fulaz Petroleum, was granted a license by the Dire Dawa Administration Investment Commission in May 2005 and acquired a 150,000 m² plot in Melka Jebdu area to erect a factory with a production capacity of 1,200 tons a day at a total cost of 936 million Birr. It is now undertaking the construction of a warehouse, while the factory is planned to go operational in two years. When the factory becomes operational, it should be able to produce 2,500 tons of cement a day, a capacity close to the largest state owned cement factory, at present. The last but largest entrant to this picture is Derba Midroc which has earmarked a modest 2.6 billion Birr to produce 5,000 tons of cement per day when it launches its first stage after two years on 200 hectares of land it acquired in the Derba area of north eastern Shoa in Oromiya Regional State. This figure alone will increase the present cement supply rate by 100%. The state owned Mugher is also bustling about to expand its plant by constructing two clinker mills at a cost of one billion Birr in the former Tatek military camp used to be, south-west of Addis Ababa with an outlay of 1.5 billion Birr. When the new mill at Tatek goes functional after a few months, Muger’s daily output capacity will rise from the present three thousand tons per day to five thousand. Construction Ahead, mar-apr 2006
11
in
brief
Contractors Sign for all 15 UC
Beles supply contract signed VA Tech Hydro has signed a. 89.5 Mln USD supply contract for the Beles hydro power plant in Ethiopia. The order was placed by Salini Costruttori, which is going to be the turnkey supplier of the 460 MW plant. Owned by the Ethiopian Electric Power Corporation (EEPCO), the plant will be installed in a cavern located in the northwest Ethiopia, near to lake Tana. The scope of supply of, goods and services for this project include model test, design, manufacturing, transport, installation and commissioning of the complete electromechanical equipment including four vertical Francis turbines, digital type governors, generators and electrical and mechanical balance of the plant. The start of commercial operation is scheduled for 2008. Beles will be the largest hydro power station in Ethiopia and is to be one of the first plants feeding the country’s planned 400 kV grid for long distance transmission. Satcon Clinches 434.6 million Birr Road Contract Satcon Construction Sc has signed on 28 April 2006 at the authority’s meeting hall a contract billed at for 434.6 million Birr. Delbina-Jinka 120 km road contract tendered by Ethiopian Roads Authority. The Delbina-Jinka road is the third phase of the larger Arbaminch-Jinka road construction project. The previous two phases that were combined under one project are now underway with Sur Construction. The Delbina - Jinka road has been there as a gravel road. Through time the road has deteriorated to the point where transportation on it has become difficult. The upgraded road to be built by Satcon will have a width of 6.7 m and 1.5 m shoulder on either side. The project supervisors are from Britain, Michel Parkman working in collaboration with the local company, Civil Works Consulting Engineers. When the project is completed after three years, it is believed that development and economic growth in the area will be facilitated. The Jinka zone is known for its export coffee production in addition to other agricultural products it supplies to local market. The southern part of the area starting from Arbaminch is also an important tourist attraction for its diverse cultures and peoples.
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Construction Ahead, mar-apr 2006
B
etween mid April and early May, GTZ International Services (GTZ IS) a component of the German technical development cooperation agency GTZ, signed contracts with 14 contractors (Grade 13) for the construction on all of the 15 sites of the University Capacity Building Program (UCBP). Acting on behalf of the Ministry of Education and the Ministry of Capacity Building, GTZ IS is the project Management and Implementating agency responsible for overall project management. The University Capacity Building Program (UCBP) will construct 11 new universities and expand two existing ones at different sites throughout Ethiopia over the course of four years. The “capacity building” refers to the training, workshops
and skill-upgrading that GTZ IS provides to the construction companies, construction management companies, architects and engineers and small and medium enterprises participating in the project. The UCBP’s overarching objectives are twofold. One is to expand Ethiopia’s system of higher education in an equitable manner. The other is to increase the competitiveness of Ethiopia’s construction/ engineering sector. In expanding the system of higher education, UCBP will create over 121,000 new opportunities in higher education all over Ethiopia. In working towards increasing the competitiveness of the construction/ engineering sector, the UCBP is using these 15 construction sites as classrooms for providing skill‑upgrading to workers
CBP Construction Sites that focuses on the following five professional groups: concrete builders, masons, carpenters, electricians and plumbers. At the same time, UCBP upgrades companies at firm level with management training workshops such as human resources, marketing, procurement and quality management. The bid for the construction of the universities was tendered under five packages that categorize the sites by regions, contractor size (Grade 1-3) and according to three different climatic zones. Sites in the hot and dry category include Adama, Dire Dawa, Jijiga, and Semera. Alemayehu Ketema signed the contract for Adama. Dire Dawa and Jijiga were awarded to Flintstone Engineering while Sisay Desta building contractor secured Semera. Sur Construction signed the contract for most northern site, Axum, which falls into the second category, cold and temperate. The contract for another cold and temperate site, Robe, was signed by Century 21 Construction. For the sites of Desie and Kombolcha, also in the same climate category, two contractors will collaborate on each site: Orbit Engineering and Equator Engineering in Desie and Africawit Building Contractor and Tewodros Abere in Kombolcha. Tekleberhan Ambaye Construction signed a contract for another cold and temperate site, Debre Markos, and contracts for the last two sites in this category, Debre Birhan and Sodo, went to GAD construction. GAD Construction has also signed for a humid/ plateau site, Dila. Out of the other humid/ plateau sites, Nekemte was awarded to AMB Construction and Nasew Construction signed for both Mizan and Tepi. Four consultant companies (Fasil Giorghis, Geretta Consultant, BET Consultant and Abba Architects), working in association with GTZ IS’s project partner, MH Engineering, have created four building designs adapted to the geographical characteristics the 15 sites. Further adaptation, according to the climate as well as topography, has been achieved through careful master planning by consultants in collaboration with the GTZ IS planning unit. Construction Ahead, mar-apr 2006
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world news
Burj Dubai workers riot By Richard High, International Construction
C
onstruction workers rioted at the Burj Dubai site in Dubai, United Arab Emirates on 21 March, in protest against low pay and alleged mistreatment.
Italian Regime Change By Peter Reina - Engineering News-Record
I
taly’s 5-billion USD, 3.7-kilometer-long Messina Strait bridge will not be built, if the new national government’s environment minister Alfonso Pecoraro Scanio gets his way. A final design/build contract was signed past March after many years of planning. If built, the project would have included the world ‘s longest suspended span, at 3.3 km.
The men, largely immigrant workers from Asia, work for subcontractor Al Naboodah Laing O’Rourke on the Old Town part of the Burj development. Their demands include better pay, working and living conditions, including better medical care, and fairer treatment from site managers. Pay in Dubai currently ranges from USD 7.60 per day for a skilled carpenter to USD 4 per day for labourers. The violence erupted when buses due to take the workers to labour camps at the end of their shift were delayed, caused an estimated AED 3.7 million (USD 1 million) of damage. Local press reports said about 2500 workers chased and beat security officers, then broke into offices where they smashed computers and damaged files. About 20 cars and several pieces of construction equipment were also destroyed in the disturbances. The men returned to the site on Wednesday but refused to return to work. Thousands of Al Naboodah Laing O’Rourke labourers building a new terminal at Dubai’s International Airport also stopped work in a sympathy strike. The government and police have threatened the workers with deportation if they do not resume work. Last year several strikes hit the UAE’s construction industry as workers sought better working and living conditions, while at least 24 Indian construction workers committed suicide in Dubai last year. The Indian Consulate in Dubai blames the deaths on a lack of social support and feelings of isolation among expatriate workers.
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Construction Ahead, mar-apr 2006
Manitou takes legal By Murray Pollok Access International
M
anitou has started legal action against MEC Aerial Platforms and its European dealers over an alleged infringement of its rights to sell the MEC scissors in Europe. Manitou said it holds the European sales rights to the original MEC scissor designs and claims that MEC Aerial Platforms - which is producing updated versions of the MEC scissors - is marketing its products illegally in Europe. Bruno Fille, Manitou’s executive vice president and group development director, told Access International that Manitou had initiated
Could Topple Big Span Minister Scanio reportedly vowed to divert the bridge’s funding to rail construction on the mainland. Scanio, leader of Italy’s Green Party, is part of the fragile new government coalition of Prime Minister Romano Prodi, who recently narrowly beat Silvio Berlusconi in national elections. Government-owned project developer Stretto di Messina S.p.A is now waiting to hear the formal government view. “The decision has to be taken with all the ministers involved,” says company spokeswoman Manuela Zucchini. In case of cancellation, the construction joint venture would be compensated for bidding and design costs to date, she added. A consortium led by Milan-based Impregilo S.p.A. signed a contract to develop the system’s design over 10 months. It was then to build the bridge and linked railroad during the next five years. The consortium, which also includes Japan’s IshikawajimaHarima Heavy Industries Co. Ltd., is using engineers from Denmark’s Cowi A/S and Sund & Baelt A/S, and Buckland & Taylor Ltd., Canada, to design the project.
action against MEC legal action in Europe several weeks ago after unsuccessfully trying to reach a compromise agreement with MEC. “We will defend our rights on the European market. Clearly in Europe there is an issue for them. We are the owner of the patents and drawings.” Mr Fille said Manitou would take legal action against anyone trying to sell the MEC products in Europe as well as the US manufacturer. Construction Ahead, mar-apr 2006
15
Hats Off to Saluda
A
fter setting a North American record for the most roller-compacted concrete (RCC) placed in a single day—14,213 m³—the Saluda Dam Remediation Project has been honored with the American Society of Civil Engineers’ 2006 Outstanding Civil Engineering Achievement award. The project involved building a backup replacement dam for the Saluda Dam, which impounds the 22,300 hectare Lake Murray west of Columbia, South Carolina. This backup dam is necessary because if another Charleston earthquake occurs, as it did in 1886, the existing dam would fail and put more than 100,000 lives at risk.
library
Egyptian Showroom
When completed in 1930, the 2.4 km, 61 m dam broke a number of records. It was the world’s largest earthen dam, the word’s largest hydroelectric dam, and impounded the 202 km² Lake Murray, the world’s largest man-made lake. In addition to the nearly one million m³ of RCC, workers placed 23,000 m³ of conventional mass concrete and 54,400 m² of precast concrete facing panels using more than 8,350 m² of 5000‑psi concrete. The RCC design mix used 68 kg of cement per m³ and 68 kg of bottom ash that had been landfilled on site for the last ten years.
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nternational architects Gensler have been appointed to design the new headquarters for AlMansour, the General Motors distributor for Egypt. Located in the heart of Cairo’s rapidly evolving business district, the new building is designed to streamline Al-Mansours’ business needs in the region. This is achieved by integrating the firm’s corporate headquarters, showroom, parts and services facilities in to one building. This, according to Gensler, will give customers and the building’s other users a unique service, retail and corporate experience in line with the Mansour and GM brands. In Gensler’s proposed scheme the glazed corporate wing “ascends horizontally juxtaposing the descending showroom, creating a dynamic winged structure”. To one side of the building a moat reflects light into the showroom space as the customer approaches the entrance. The building offers “individually tailored showroom, service and corporate experiences” that “merge on the first floor interaction lounge level”, which contains terraces, retail outlets, cafes and lounges with views through the building and beyond.
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Construction Ahead, mar-apr 2006
frame fixing
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K-based Zaha Hadid Architects has been chosen to design the American University of Beirut’s new Library. The six-storey building for the Issam M Fares Institute for Public Policy and International Affairs will create a home for domestic and foreign students and researchers specialising in Middle Eastern Politics.
The 1800 m² building will house the directors office, administration and researchers lounges, conference and workshop spaces, break-out rooms, seminar and reading rooms and a roof terrace. There will also be an underground auditorium. Construction is expected to start later this year and is due for completion in 2008.
High performance steel anchors
New Chicago Tower
C
hicago-based Studio Gang Architects has released its first designs for Aqua, an 82‑story residential and hotel tower for owner/developer Magellan Development Group. The US$ 300 million tower will be located in
the city’s new 28 acre (11 ha) Lakeshore East Development south of the Chicago River. Design principal Jeanne Gang has created a series of rippling edges in the structure’s façade, which give an undulating appearance to the outside of the building, by using a unique floor plate for each of its concrete slabs. Electrical fixing
While the apartment/ hotel room plans are conventional, comprising twelve variations enclosed by a glass thermal envelope, the exterior spaces, which Ms Gang conceived as “generous exterior terraces” rather than individual balconies, give each apartment and hotel unit its own outdoor space. Construction is expected to start later this year, with completion due in 2009.
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Tel 551 27 58, Fax 551 50 82 17 sutco@ethionet.et Wollo Sefer opposite Ibex Hotel
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or a species introduced merely a century ago, eucalyptus in Ethiopia is an enormous success. Not only has it changed the landscape but it is one of the main construction materials. Cement, glass and steel may be taking over the glitzy high rises on Bole but eucalyptus still accounts for most wood in ‘traditional’ buildings all over the country. The bahar zaf has made its way even into the millennium-old traditional pharmacopoeia of Ethiopia and is used in curing the common colds. This goes to show just how acclimatized this tree from across the oceans (bahar zaf) has become. Of the 15 different species of eucalyptus introduced in Ethiopia in 1895, the Eucalyptus Globulus has adapted most successfully. Globulus’ fast growth has made it an invaluable construction and infrastructure material known as atena in Amharic. The most extensive and immediately recognizable use of atena is as electricity and telephone poles. Though recently substituted by concrete, thousands and thousands of eucalyptus poles are still used throughout the country. Eucalyptus timber has also reigned supreme as an economical construction material for the building of houses. In 1969, a whopping ninety percent of the buildings in Addis Ababa were constructed of eucalyptus wood. Other materials may be taking over in Addis but the poles holding up the temporary corrugated iron fences on construction 18
Construction Ahead, mar-apr 2006
sites all over the city are still indisputably eucalyptus as are most of scaffolding. Blue glass and aluminium may be the rule of the day in Bole but the wooden frame of wattle and daub houses all over Ethiopia will be built of atena for quite some time to come. These cheap houses could not be built without a ready supply of fast growing timber while the aromatic eucalyptus provides ‘good cover’ to many Ethiopians indeed. But it is not only the sweet smell of the eucalyptus’s success that lingers in the air. Several species have become invasive and are causing major problems for local ecosystems. While original woodlands support numerous species of animal life (insects, birds, salamanders, and the like), eucalyptus forests are inhospitable to local wildlife, thus contributing to a decline in bio-diversity. The eucalyptus tree is also a thirsty plant. It dries up rivers and wells, leaches the soil of its nutrients and, by restricting grass cover, increases erosion. As a result of this, the eucalyptus has in recent times become the focus of protest and open hostility among farmers, forestry officials and funding bodies. The modernization of Addis is diminishing the use of Bahar zaf in construction: this hardy wood is not a finishing material fit for the 21st century. But the easy going eucalyptus isn’t beaten out of shape yet. The atena are still there, on every construction site, helping to put up buildings with scaffolding, false works and armatures. When speaking of eucalyptus, the negative aspects are
these days often being highlighted. For sure it may not be the best environment-friendly of plants but it has certainly contributed a lion’s share to the development of Ethiopia. Spectacularly beautiful at times, always useful, a bad weed accused of all ills by environmentalists, the eucalyptus, royally introduced by Menelik, democratized on its own merits, is here in Ethiopia to stay.
THE SHADY REPUTATION OF A brief history of the eucalyptus from it’s origins to its introduction into Ethiopia
E
ucalyptus, which means ‘well-covered,’ is the name given to an enormous and fascinating genus. It comprises around 800 species of trees, all of which, except for 12, are Australian endemic. Eucalyptuses are characterized by leathery, whitish leaves that hang vertically, their edges facing the sun, and their ragged bark and peculiar aroma. They are remarkable for their extremely rapid growth and some species in the genus are among the tallest trees known in the world. Its range extends from sub-alpine areas to wet coastal lands, temperate woodlands and arid zones. In fact, the only major ecosystem from where eucalyptuses are mostly absent are tropical rainforests. The eucalyptus genus originated between 35 and 50 million years ago, not long after Australia-New Guinea separated from Gondwana. The genus’ rise coincided with an increase in fossil charcoal deposits, but it remained a minor component of the Tertiary rainforest until about 20 million years ago, when the gradual drying up of the continent and the depletion of its soil nutrients led to the development of more open forest types. With the arrival of the first humans about 50 thousand years ago, bush fires became much more frequent and the fire-fond eucalyptus soon came to account for roughly 70% of Australian forest. Different species of eucalyptus were introduced to the rest of the world by Sir Joseph Banks, a botanist on the Cook expedition in 1770. Eucalyptus has since taken root in many countries as a cash crop and ornamental parkland tree. But in few countries has the Australian endemic become such a fixture as in the Ethiopian landscape where it now seems as aboriginal as the typical shola tree.
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Construction Ahead, mar-apr 2006
A GRASS ROOTS’ SUCCESS But how did a tree from Australia make it to Ethiopia? In the late nineteenth century the burgeoning city of Addis Ababa suffered acute shortages of wood. But while Emperor Menelik was contemplating moving the capital to Addis Alem, some
eucalyptus seedlings were planted by his French adviser, Casimir Mondon‑Vidailhet, in 1894 or 1895. The tree grew fast and was soon extensively cultivated. Menelik quickly recognized the tree’s potential (although with some misgivings, see box below), shelved
plans to move and encouraged the eucalyptus’ development by distributing seedlings at low cost and exempting it from taxation. The capital had been saved and the face of Ethiopia’s landscape changed for ever.
Minister of Agriculture of Ethiopia
Notice
At first, at the time when the Emperor founded this city of Addis Abeba, the soil was void and had no trees whatsoever. But he imported this quickly growing Eucalyptus tree so that it might be beautiful and agreeable and pleasant to the sight. The Emperor’s intention however was to import and have planted all those useful (trees) that are useful to our country and nation, whose fruit is edible, and whose wood is useful. To find this out (lit. so that this may be known) he imported (trees) of every kind, and did not omit to test them (lit. their being tested did not lack). From all that were tested not one kind failed to grow, but all grew and flourished better than in the country where they were originally found. They (ie. the people of Abyssinia-or the Emperor Menelik) were assured of this by the large kind of plum tree ; by the mulberry, the silk tree ; by the rose tree ; by the “ Sitre.” There are also many trees and plants which resemble these. And we having seen this, it is our intention to make less the trees which are useless and to increase those which are of use (lit.let us increase). And the silk tree which is called mulberry, its fruit is edible. Its leaves are the chief requisite for persons who wish to breed silkworms. Leaving this out of the question (lit. if this be not), if people give the leaves to eat to cows, oxen, sheep, and goats, they (i.e. leaves) make them very fat. The trunk also being cut each year will be of use. It brings in much money and is of moderate height. H.H. The Heir Apparent thought that a tree which has such advantages should be cultivated. This Eucalyptus however has no use with the exception of destroying the plants and earth which it eats. If there be a spring in the vicinity, it dries it up, and sucking and drinking the bottom of wells it dries up the water. Its wood is no use and its fruit is not eaten. And now in every place let him who has Eucalyptus pull up 2/3 of it and let 1/3 remain. In place of what has been pulled up, we will give young trees which possess advantages. Maggabit 12th, 1906 A.M. Written at the town of Addis Abeba.
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ETHIOPIA WELL COVERED By Yves Stranger
U
proot, cut, slash and burn and otherwise eradicate the Maple tree of Canada. Plant Baobabs in their stead. Mow down the Scandinavian fir (I’ve never liked their Christmassy look anyway), and replace them with Olive trees (and a few cicadas). Axe the proverbial French oak under which Saint Louis gave a parody of justice, and plant a Weeping Willow for his sins. Let the Balkans lose their Chestnut trees to Mangrove forest, California its Sequoia to Taiga dwarf pine. Canada covered in Baobabs? Scandinavia in Olive trees and France in Weeping Willows? The whole ecosystem, the landscape itself would be changed for ever after. Besides, you can’t just take a species and transplant it elsewhere. It could have unforeseen consequences. Trees form forests and forests are whole ecosystems, complex living entities that have evolved together with their climates and animals. Then, there is the social and human dimension. What a Maple tree is to Canada, so the Oak is to France. You’d be digging up more than just tree roots if you were to do away with them. So you wouldn’t recommend doing, for example, planting Baobab on a massive scale in Canada? We might ask a rhetorical forester. This would draw a blank look. And for Ethiopia, then? ‘Eu...’ he says, lost for words. By Menelik! You interrupt him. He’s right! Eucalyptus always was the answer. As the apocryphal tale goes, Empress Taitu was responsible for naming our fragrant city ‘Addis Ababa.’ What most people forget to mention is that she named it after the blooms of the indigenous
Mimosa trees that once upon a time covered the flanks of Entoto and gave leafy shade to Finfinne. As other apocrypha has it, two – shady – advisors of Menelik are credited with the introduction of the tree whose name means ‘well-covered,’ the ‘Bahar Zaf ’ or tree from over the oceans: Dame Eucalyptus herself. Of these two foreign retainers who had put down roots in Ethiopia, one, who held the title of Chika Shum in some God forsaken place, was French and the other, by the name of Alfred Ilg, was Swiss. No doubt, like most Europeans brought up in the 19th century, they had been the subject of numerous cough pills while growing up. These would have been fixed with eucalyptus extracts. And on the watery heights of Entoto and Addis coughs and colds were a dozen a dime. Who knows if some cough drop taken at eight years of age is not responsible for one of the biggest remodelling of natural landscapes to have taken place in living memory? But we’ve gone off on a tangent here, a zig-zag of possible explanations looking rather like the incredible scaffolding erected around buildings under construction in Addis Ababa. What a wanton use of – eucalyptus – wood, a friend once remarked of these zed shaped structures that enable construction workers to walk to the top of the building without going up stairs. It seemed rather a sensible way of doing things to me. The same friend suggested importing Koala bears and releasing them into our local forests as a source of protein and an effort to increase the bio-diversity of otherwise rather sterile woodland – ahem, although my friend’s rather outlandish comments remain his, this writer would like to point out that Koala bears are a species endemic to Australia that feed solely on Eucalyptus leaves. For anyone who has had the chance to see some of the remains of the original forests of the highlands
with their Tsid and Wanza, their grand Shola trees, Mimosa and Acacia, my friend’s comments, however tongue in cheek, will find an echo. Some of the primal forests to be still found near the capital, for example in Menagesha or a little further out, near Atse Menelik’s old haunts in Ankobar are wondrous places full of a whole range of life, from primates to birds and bushbucks. Even up Entoto, there are pockets of forest untouched where the original Mimosa still thrive and Olive baboons can be seen foraging the undergrowth for food. Eucalyptus woodland is an altogether different experience. The forest may grow sky high in a number of years to be counted on the fingers of both hands. But it has some serious drawbacks. In young plantations, although the soil is often deprived of most of its nutrients, grass grows between the coppiced stumps and farm animals can be found grazing. The older forest lies in eerie shade – didn’t we say that Eucalyptus means well covered? - and the silence is only broken by the fumbling of women gathering twigs and dried leaves for fuel. Few birds, less mammals. As I write these lines, in Old Airport Addis Ababa, the skyline outside my window is taken up by swaying trees; in the sunlight they are blue rather than green. An Abyssinian fly catcher with its long white tail streaming out behind it stands out against the bluish mass, like a fire-fly in a deep night. Eucalyptus are also beautiful, majestic even, when left to grow, not just match-sticks waiting to be harvested. The Australian tree saved Addis Ababa and probably in some sense, Ethiopia as well. Without it, not only would development as we know it have been impossible but even more of the country’s ever dwindling original forest would have disappeared. There is no case against Eucalyptus as it has come to occupy an indispensable place in Ethiopia. And we’re not talking just money here. Even as the Oak is not only a tree to the French but something symbolic of their identity, the Eucalyptus has put down deep roots into the Ethiopian heartlands. Bahar Zaf it may well be named but the all pervading smell of Eucalyptus forests and the shimmer of their bluish canopies shivering in the wind are as true to the Ethiopian landscape as the sight of a pair of mottled oxen churning up red soil. Besides, borrowing is not a one way graft: the hills of Ceret, the market town in southern France where I grew up, are covered in Mimosa scrub and are famous for their yellow blooms. No doubt my facetious Koala loving friend would suggest importing some Olive baboons to roam these ‘African’ forests. And renaming the village Finfinne, by Menelik! Construction Ahead, mar-apr 2006
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CONSULTANCY SERVICES IN ETHIOPIA Past Development and Future Trends by Wouhib Kebede
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fter the end of the Italian occupation, there was an immediate need to plan social services and to give adequate attention to training manpower required for the civil service of the fledgling new administrative set-up. This may have been the first instance when designers were commissioned, on a large scale, by the Ethiopian government to prepare plans for new institutions. The red brick buildings of several educational institutions are a witness of this endeavour. The University College of Addis Ababa, the Technical School extension, the General Wingate School and similar others may be mentioned in this regard. The next important period, representing a relative building boom spans the 1960s. This period brought to the scene established architectural interests with local branches operating on a permanent basis. All of them were run by foreign principals and staffed almost entirely by expatriates. We remember the big names from the signboards, which announced their names and the landmark buildings that house the most prestigious institutions and are still considered as good pieces of Architecture. Architects, offices such as Henri Chomette and Arturo Mezzedimi along with the prominent contractors like Alexander P. Myrialis and Giordano Concetto graced the urban outdoor with signboards and provided the inspiration for many young students to study architecture. When the 24
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School of Architecture was established in 1961-62, by the world-renowned authority on color perception and architectural theory, Sven Hesselgren, the stage was set for Ethiopian architects to make a head start to take over from the foreign practitioners. The first batch of students of the School of Architecture graduated in 1967, but neither the established offices nor the government ministries were ready to absorb the small number of graduates. Although by 1972 the total number of graduates didn’t exceed forty, employment opportunities were extremely bleak. Conditions were also not favourable for setting up a private practice in a sector tightly controlled by experienced foreign professionals who had established firm contacts with the ruling class. Despite these very unfavourable conditions, pioneers such as Ato Assefa Bekele, one of the first graduates of the School of Architecture, endeavoured to set up the first local consulting firms in the early 1970s in collaboration with other Ethiopian professionals. The turning point in the development of architectural practice came with the revolution of 1974 that opened opportunities to nationals and at the same time witnessed the gradual departure of the expatriates. The enrolment at the School of Architecture also showed a marked increase. In the 1970s and 1980s most of the design work for government projects was undertaken by technical
departments of government the one that has put up a banner ministries and through the Ministry on one of Africa Avenue’s of Works. Consultancy firms with light posts. The opportunities Ethiopian principals also began to for self‑employment and the be accredited during this period. determination of young architects Directives for the registration of and structural engineers to exploit professionals and consulting offices this chance, is to be commanded. were, as far as some documents On the other hand, if this trend indicate, put into force as early is not regulated properly, it will as 1983. Most consulting offices lead to a stagnation of professional were small practices set up by capability, and the inability to individual architects and have undertake the design of projects stayed much the same to this day. that require specialization and This gave rise to the aspiration among young architects of replicating the experience of their predecessors We have come a and establishing their long way from the early seventies own one-man offices. where the economy was not able to The establishment of find employment for half a dozen the Building Design graduating architects. Enterprise, however, played a positive role in the development of professional expertise by providing an organized set up where a large number of professionals teamwork. with different levels of experience There is a shift in the perception and from different disciplines got of the basic requirements of the opportunity to work on a consultancy service both among variety of projects interactively. professionals and most importantly Since the mid 1990s the among the authorities that issue proliferation of small practices the licenses. The active role of and the repeated redrafting of professional associations is crucial the government directives on at this juncture to redirect the registration and licensing have process to the correct path. I created a confusing scenario. The recall a statement from the most directives have failed to regulate unexpected quarters hinting the performance of the licensed that a consulting office may be offices and have done nothing to established by a non-professional. promote partnerships and public This would mean that a biologist owned offices. This coupled with may set up an architectural design the emergence of a new active firm, appoint himself as manager, private sector engaged in real employ a few architects to fulfil estate development, has paved the licensing requirements and the way for the flourishing of go on with business as usual. To freelance service and the growing see how outrageous this is, one marginalisation of established may only have to mention those practice. A report by the Addis who license lawyers or the lawyers Ababa ICWA (Infrastructure and themselves. Construction Authority) lists over Some of the dangers of the status 100 consulting firms, of which less quo are already manifesting than a third are members of the themselves. We have already heard Ethiopian Consulting Engineers of quite a few instances concerning and Architects Association. building projects where possible There are numerous other offices catastrophes was averted at the operating unofficially, including
very last moment, often with the intervention of experienced professionals availing their services unreservedly. There are definitely many projects out there, where owners will have no one to hold responsible in the event of some unforeseen mishaps. A growing number of investors, who regard themselves as smart by aggressively looking for dirt-cheap design fees, are running such risks. These types of developers are also working against contractors by reducing them to mere providers of labour. A good chunk of the blame for the demise of professional consultancy work obviously lies with principals of the established offices. It must be noted that, with the exception of the few up and coming offices, most principals are no longer involved in actual design work. Junior architects handle some of the most demanding design work in most offices. With the absence of a career structure, both junior and senior architects are treated alike, and the need for either collaboration or consultation is seldom felt. An atmosphere of rote practice has also taken a deep root among principals and professionals alike, fuelled by the fish munch fish mentality of wining commissions by undercutting competitors. We have come a long way from the early seventies where the economy was not able to offer employment for the half dozen graduating architects. Today, there is enough work both in the public and private sectors to occupy more than 500 architects and an equal or even more number of structural engineers. The technology and facilities have also greatly improved, making our work potentially more efficient and more precise. But we are not taking full advantage of this opportunity, and our performance is in a steady decline, as disclosed by some frank principals, and as can Construction Ahead, mar-apr 2006
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be easily discerned by comparing project documents from the two eras. We have also failed to give due attention to the constant erosion of the integrity of our professions by parties who have little respect for architecture in particular and the construction industry as a whole. nevertheless there is a bright future for consultancy services, in the building sector provided we chart an appropriate path of restructuring our mode of operation. The starting point for such an undertaking is undoubtedly strengthening our professional associations such us the Ethiopian Consulting Engineers and Architects Association. Obviously these associations should not be geared towards excluding non-members and restricting membership to a tight knit group. We must also endeavour to encourage broad‑based partnerships and public owned design firms to take root, before multinational firms engulf us. Government efforts to regulate the construction industry and promote professional practice must be actively supported. Drawbacks of existing directives and legislation need to be brought to the attention of the authorities and effective means of reviewing them suggested. Technical documentation for common use unquestionably, shall have to receive a fresh new look in light of the new conditions under which we operate, and the embarrassing instances we have faced in the past with copying without a second thought. A minimum fee structure, together with an acceptable quality and detail of deliverable, is also essential to do away with cutthroat competition. The restructuring of the Building Design Enterprise, which has been an active member of most of the professional associations and a founding member of the Ethiopian Consulting Engineers and Architects Association, has a
very important role to play in this respect. Many professionals, who have had the opportunity to be employed there, dub the enterprise the ‘second school’. It is a model for public owned design offices that will definitely appear in the near future. Its organizational structure is a showpiece of what is missing in private offices, in terms of a career structure and learning through constant interaction with professionals of different depht and degrees of experience. We hope that its two decades of service in the sector will be instrumental in redirecting the rendering of consultancy services to the proper path. The restructuring of this government agency as a share company clearly indicates the government’s intention of eventual privatisation. Whether this would be followed up by other design offices of similar organization and size is difficult to predict. The Engineering Capacity Building Programme, being undertaken by the Ministry of Capacity Building and Ministry of Education benchmarks best international practices and intends to implement capacity building of construction management and design firms through the University Capacity Building Programme. We may, therefore, see in the near future ISO quality certified local design firms operating not only in Ethiopia, but throughout the East African region and beyond. Other factors that have contributed to the upswing in the construction industry may also present opportunities of growth and reorganization to the small practitioners that have sprouted in the last three years. On the other hand, the decline in sector which is destined to come, will inevitably entail specialization or re-grouping. In both cases, as international trends indicate, it is certain that consultancy services in Ethiopia are en route for some drastic changes for the better.
perspective
LESS VALUE TO TIME LESS SUCCESS! by Wubishet Jekale Mengesha (Dr Engineer) Assistant Professor and practising professional in construction management and structural engineering
Focus on time planning
T
he construction industry in Ethiopia changed its procurement regulation with regard to completion time since 1994. Thereafter, practices showed that completion time is set by employers without due consideration for time planning. Contractors gives little consideration on completion time and submit their tender largely on the basis of tender prices. This practice has derailed the industry from actively engaging in time planning and it is now found to be one of the major causes for excessive delays. This writing tries to address this issue in a professional setting and argues that less attention given to time planning leads to less success. Changes are natural and their management is a part of
4. Three ways to decrease critical tasks’ duration
contract administration. They should be dealt with alternative
¤ Assigning more resources and overtime work
approaches.
¤ Add lead time to critical tasks
The following four different approaches are recommended when construction projects are faced with delays: 1. Three main approaches for rescheduling ¤ Changing the critical task ¤ Decreasing the duration of the critical task ¤ Optimizing the overall project schedule. 2. Three approaches to change the critical path ¤ Changing the task dependency ¤ Changing the task type / constraint ¤ Breaking down a critical task into non-critical sub‑tasks. 3. Three ways of optimizing the overall project schedule
¤ Using parallel paths - concurrency. • When things change and a task moves off the critical path, look for opportunities to shift slack resources to the new critical tasks. • If we don’t optimize the in-process changes continuously, we wind up managing past problems rather than anticipating emerging problems and dealing with imminent issues. • When concurrency is used to shorten schedule in project plans, we need to watch out the use of redundancy in resources and consequently, additional cost due to them. These concepts are part of the construction management
¤ Watch out the in-process changing critical tasks
body of knowledge with which contemporary construction
¤ Watch out near critical and / or parallel tasks
management professionals are qualified with. Hence they are
¤ Integrate targets, milestones and in‑process
capable to tackle such problems and enhance the performance
changes.
of construction projects.
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Tel. Off 011 6636671 Fax/Tel 011 6623548 P.O.Box 27101 Addis Ababa, Ethiopia E-mail: pgatech@ethionet.et
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The grey powder Crisis of a strategic binder By Tzedeke Yihunie C. Eng., Flintstone Engineering
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C
ement is a binder, a sort of glue, used to bind solid particles of varying sizes into a dense artificial stone such as concrete or a matrix of blocks as in brick walls or a thick stable surface as in plaster. In ancient times, long before the advent of cement as we know it today, clay mud was the choice binder. It is still the only choice in many rural Ethiopian stone works. Of course the use of lime and gypsum as binders was not a much younger exercise either. The Pharaohs used it to build their massive edifices. But of all ancient cements, that of the Romans’ — of about the first century B.C. — which featured Pozzolona from Mount Vesuvius was by far closer, in merits, to the present day hydraulic cement. The modern hydraulic cement, we owe to an enterprising British Engineer, whose experiment of a binder on the building of a lighthouse off the coast of Dover in 1756, gave a useful life of 120 years to the tower and launched the beginning of a product that would be manufactured at a rate of two billion tones per annum, two and half centuries later.
The introduction of cement to Ethiopia as a construction material is probably at about the time of European incursion on the Red Sea ports. Its manufacturing definitely started in 1936 at Dire Dawa. Established by the Italians, the factory was at the time able to produce 36 tons per annum of cement and lime. The establishment of the Addis Ababa Cement Factory in 1964 , Mugher in 1984 and Mesobo in 1998, are the highlights of the Ethiopian cement industry. Technologically, Mesobo’s Danish-made plant is the culmination of Ethiopia’s advancement in the cement industry, to-date, of course. In 1999, the government put the Addis Ababa, Dire Dawa and Mugher factories under one corporation. By then, the factory in the capital had been reduced to a grinding and bagging plant for clinker (the penultimate output of cooked clay-lime-and-some) produced at Mugher. With government expenditure on construction increasing by 250%, from around Birr two billion to around five billion since 1998, and with an even more accelerated private sector investment in plant and property, cement has become a vital resource.
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It has become vital in the tactical as well as the strategic sense. Studies estimate current demand at twice more than the combined maximum output of the three operating factories, which stands at 6,400 tons per day. (Mugher at 3000 tons per day, Messobo at 2000 tons per day and Dire Dawa at 1400 tons per day).
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That is, current national demand can only be satisfied at a sustained output of more than 10,000 tons per day. The same studies estimate demand to grow at a highly accelerated rate of 15 to 20% per annum. Also likely is that, for a country that shows a purchasing power parity (PPP) to per capita income ratio of more than seven, the rate of change of demand may soon be higher than anybody’s wildest expectation. If and when a critical set of favourable economic factors prompt high productivity, sustained savings and, finally, the translation of those savings into a combination of investment in property and consumption, then, cement may become as good as gold.
But that is a long way off. At present we only have a shortfall of 5,000 tons per day to satisfy. Still, despite mankind’s acquaintance with cement for thousands of years, why is there so much shortage? The reason is a combination of many events, some progressive, others detractive or even reactionary. The most significant cause, and also the most positive, is the fast growth of regional urban centers as a consequence of the recently established federal political structure of the country. Federalism also has induced geographically more equitable public and private construction procurement. Prior to Mesobo’s entry into the industry in 1998, only the publicly owned Mugher supplied this fast growing demand. And, for decades the government seemingly maintained its sole plant as a cash cow of its industrial portfolio. Proceeds from Mugher, hundreds of millions in operating profit, instead of being partially invested in the expansion of the industry, were channelled into a more urgent priority augmenting a recurrent or capital budget deficit. This may partly be owing to an underestimated demand-supply parity. Or it may be due to the hope of attracting would-be investors by creating, so to speak, a non-hostile, ripe industrial market. But investors, foreign or local, were not responsive enough to fill the vacuum. With the exception of Mesobo, which has situated itself in the geographically uncompetitive northern corner of the market, no other plant dared into this seemingly lucrative sector. As for foreign cement, even if the issue of tariff was to be economically overcome, there still remains the high cost of overland transportation making the options unattractive to sellers and buyers
alike. Cement from the Middle East has recently found some market in the western parts of the Somali Regional State where the Oman brand sells 20 to 30 % lower than the local. All in all, it looked as if the cement industry, used to a command economy to satisfy a predetermined demand, lacks the direction and vision required to streamline the fragmented requirements of a budding market economy. As vital a multiplier as cement is to the sustained economic growth of a developing country, its shortage can also exert an effect that can induce substantial contraction of the national economy Urban development with sustained housing construction, energy
Despite mankind’s acquaintance with cement for thousands of years, why is there so much shortage? The reason is a combination of many events .... and food security with timely completion of dams and power plants, market connectivity with roads and telecom, social equity in nurturing small and medium enterprises — all these depend on an uninterrupted construction. And that, in the present Ethiopian construction industry context, translates to uninterrupted supply of cement. In their preliminary findings from the Housing Construction Value Chain Analysis for Ethiopia, Global Development Solution, consultants jointly contracted by the World Bank and the contractors associations, has deduced that the procurement of cement is a process of paramount value to the housing construction sector. The same preliminary study shows the proportion of cement’s value
for housing to be about 20%, at the supply shortfall of 800,000 tons per year. (Total demand was estimated at 2.5 million tons per year. In an interesting observation, this study also compared the time taken to satisfy 60% of sample buyers’ demand by either one of the two dominant factories, Mesobo and Mugher, to the time taken to satisfy the shortfall (40%) by the informal speculative market. The former took more than four and half months while the latter only seven days. In June 2005, sale of ordinary Portland cement was suspended by Mugher to all buyers but one. That buyer was an international contractor employed for the construction of a fast track power generation project. Many cried foul. But this was neither the first nor will it be the last. Discretionary prioritization of such a vital resource is a necessity for a government engaged in developing one of the world’s most backward cases of infrastructural development. A similar project in the north, the Tekeze Hydro Power Project featuring a 185-meter high concrete arch-dam, has no need to elbow out demands made by less prestigious ventures. There was Mesobo to oblige. When the project was launched, critics, the author included, were skeptical, to say the least, about the location of EFFORT’S bold initiative. In retrospect, conventional wisdom now is, if it were not for Mesobo’s factory and distribution network, there would have been an economic stagnation of huge consequences. So much has come to depend on adequate cement supply. But with so much at stake and so much needed, what is to be done? By far the most rewarding of all approaches in tackling a problem of large magnitude is a shift in Construction Ahead, mar-apr 2006
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focus to fit the scope of the magnitude. There must be a shift from the tactical focus to the strategic. Cement is an issue of large proportion: it requires strategic thinking and action.
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It can not be left entangled in a maze of bureaucracy, nor can it be properly dealt with by discretionary entrepreneurship, it requires strong visionary leadership founded on a lasting consensus among all stakeholders. One issue of contention in the build up to the consensus may be the varying priorities of vested interest groups. Here, the role of the leadership in sharing a vision of a pie large enough for everybody will be paramount. I believe the government has a well-articulated strategic mission for the construction sector. What is needed is the integrating cement of its stakeholders within the strategic formulation. At the same time the state can and must allow a paradigm shift in its industrial portfolio: Mugher cannot sustain its status as a cash cow for long. Proceeds must be invested on new plants. Better still, any surplus anticipated can be substituted by an equivalent tax levy and the plant placed on the Privatization Agency’s auction block. The form of sale can be designed to reflect the importance of the commodity to the objectives of our pressing development needs. Privatization may induce creative management, innovative production and distribution process and may even reflect a more conducive environment to would be industrial investors/ competitors. And if there happens to be even an inkling of the potential to invest (which there is, indeed), then the state must do its level best to attract these with incentives that are compatible to the strategic
importance of the industry. All should not rest on the shoulders of Atlas. It will be a long time before the fruits of strategic leadership and supplies from new plants narrow the wide gap between supply and demand. In the meantime, designers, constructors, home builders and urban planners can do a lot to help. Lime is still a good binder for building elements not exposed to severe moisture variation. Designers can proscribe appropriate building elements where cement is too far or too expensive to incorporate (incidentally, one disadvantage of large cement plants in underdeveloped economies, among many, is that their economies of scale cannot be expanded to include remote construction markets. The inaccessibility of such remote areas, in most developing countries, makes cost of transportation high in proportion to the total cost). Urban planners can also enforce the use of appropriate building blocks such as natural stones, bricks, hydra blocks, and the like. Numerous houses are built with redundant structural elements and accessories with neither functional nor aesthetic value. Urban planners and regulators can help by advising the substitution of stone foundations instead of footing pads, brick stone arches and columns in place of concrete structures wherever possible, as in stable soil conditions located in low-seismic zones. Above all, we can reduce the current stress on the market by doing bits and pieces that add up to some measure of substance. For instance, in a market exhibiting chronic shortage of goods, hoarding is estimated to account for 10 to 20% of supply shortfalls. Since the primary cause of buying more than one’s
need is lack of information about the future, transparency on the part of the manufacturers and, if possible a reliable short-term supply forecast, will do a lot to reduce this problem. Developing a good working partnership between transporters and manufacturers can create the forum by which these two key players can stabilize the market by conducting mutual resource levelling exercises. Good management will also help at all three levels: at plant, marketing and distribution. Bottlenecks crop up all too frequently: at loading points, at ferrite sources, at feedstock supply points, and the like. Extra management hours to anticipate and deal with such mishaps can mean a lot for an industry in crisis. There is also an orthodox way of inducing some efficiency into the market - to conduct weekly auctions of part of the supply, holding onto the remainder for high priority public construction projects. Rationing is the unpleasant bi-product of price control. And it is also prone to corruption. Auctions, on the other hand, impart not only legitimacy to the transactions, but also enforce the efficient use of liquid assets. (Of course it may also trigger a speculative frenzy, if credit policy was lax, which it is not, by any standard). This may also trigger incentives for the substitution of cement by innovative and creative means. The distribution of cement has also a floaw (pun not intended), the analysis of which may yield a few latent tons of it here and there. The most obvious hindrance is that of maintaining too many loading-unloading points between the plant and the final user. Another is the limited number of modern and reliable trucks with high pay loads operating in cement distribution.
applying the right cement-aggregate proportion, based on engineering requirements, instead of always sticking to the safest conventional wisdom. Media blitz in this regard, like those provided by water suppliers, may help. Attending to the above and similar issues will enable us make the most out of the existing industrial capacity, a concept celebrated by the phrase “akmin amuato metekem� (using up one’s capacity to the last).
Construction engineers can also economize on cement consumption by avoiding wastage and
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But the future cannot be otherwise but bleak if the fundamental issues are not resolved for the long run. Midroc’s launching of the Derba Plant, East Africa’s partial acquisition of Dire Dawa, Messobo’s continuous process of improvement and Mugher’s belated but still spectacular response to the market by launching a 100% expansion program, all indicate the future is not beyond repair. These ventures may hold on despite the skyrocketing cost of fuel or the chronic stress on the value of our currency due to the foreign trade imbalance. They may start closing the demand-supply gap in time before the onset of economic stagnation or contraction of our fledgling economy. Notwithstanding this, the fundamentals of matching manufacturing capacity with that of national demand requires policy and measures guided by a good micro-economic sense.
And good economic sense is arrived at by mobilizing stakeholders to aspire, and strive, for a long term common welfare. In the micro-economic sense, according to the concept of price elasticity and Alfred Marshal’s three time periods of equilibrium, justice is delivered to the stakeholders in three stages. Presently, the supply is fixed and satisfies the highest bidder at any price (or the most prioritized at any cost). At this time the elasticity of demand may be close to zero, for a capital intensive industry such as cement. In the short run, the measures taken by designers, builders, policy makers and entrepreneurs investing in cement and substitute binders, may establish a second stage equilibrium- with a lower price at a slightly higher elasticity. But in the long run the market will stabilize at a higher volume and a price lower than the short-term point of equilibrium and much
lower than the time of the shortage but it will never recede to the price before the crisis. All this depends on how well the economy is steered by policy makers and business in the long‑term interest of all stake holders. It is high time that the issues connected with cement in this country are guided by ideas generated from common economic sense and consensus. It is time we establish a public body for the strategic management of cement, something like a Cement Board. We would then know where we are going or at least who to blame for our failure for not going anywhere. In the meantime, while critically considering the suggestions given here above, all concerned must do more of the good things they have been doing and, if possible, none of the bad ones.
building ever since!
Rockon Construction - Tel 091 - 124 89 92 - P.O.Box 81062 Addis Abeba, Ethiopia rock@ethionet.et
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The semantics of cement I
f Plutarch were to write a Parallel Constructions as a sequel to his Parallel Lives, his comparisons of the Romans and the Greek would likely have been about their preferred binders. Where the Greeks used only lime and over stretched their singular building elements for lack of means to reliably hold on together shorter blocks, the Romans, thanks to their pozzolona, had concrete-opus caementium-made from Roman cement, which enabled them to stretch structures as well as their architectural imagination. Roman cement was primarily a volcanic ash with some parts of slaked, ground lime added in some cases. The legacy of the Roman Empire in the form of its magnificent vaults, domes, bridges or temples – all these we owe to this art of the Roman builders. But the greatest wonder of Roman concrete was in its hydraulic character – its durability under water. And this valuable attribute has endured to this day in the remains of the Empire’s aqueducts and bridges found mostly in central Italy. It was in search of this hydraulic binder that, in the mid 18th century, a British Engineer, John Smeaton, was experimenting with various mixtures of mortar in England. He was searching for a lost building art. His experiments were rewarded and in 1759 he built the Eddystone Lighthouse, off the coast of Cornwall, using a binder made by burning a mixture of clay and lime. The lighthouse stood intact for 126 years. But it seemed that the good engineer did not follow his discovery into the stream of trade. Rather, in 1824 a bricklayer by the name of Joseph Aspdin, also of England, made a similar discovery, did take out a patent and named it Portland Cement after the Isle of Portland, the quarry stone of which resembled his patented product. But little did Aspdin know about the chemistry of cement. In the decades that followed, the plains of North Kent were covered by numerous producers that fed the growing demand for this novel concrete maker and it would be seventy five years later that the “bee hive” kilns of Kent were to be replaced by the
efficient, first generation rotary types, which made the mass production of controlled good quality cement possible. By this time, even Japan (1883) and China (1904) had commissioned their cement factories. And the USA, with Thomas Edison’s cement enterprise introduced the 150 foot (50 meter) long rotary kiln. By this time Portland Cement, the cooked and ground-lime and clay binder became synonymous with hydraulic cement. Pozzolona cement was all but forgotten. But, what, scientifically, is hydraulic cement? It is a mixture of four principal compounds : dicalcium and tricalcium silicates with small amounts of tricalcium aluminates and tetracalcium aluminoferrite. To form these compounds, clay or sand is used as a source of silicon, while lime supplies the calcium. A dash of bauxite and iron ore provide the rest. Burning this mixture at a temperature of up to 1500 °C in a rotary kiln fuses the substances into a mixture of new compounds. Carbon, an unwanted element in the binder, is removed and the silicates, aluminates and ferrites are formed. The molten, lava‑like, mixture cools to form what resembles a road cinder. This material is called clinker and when ground to the size of ashes, ordinary Portland Cement, OPC, is obtained. The whole process is carried out for one purpose: to obtain a fine powder, the constituent substances of which will fuse upon hydration, i.e. when wetted with water. As the setting time can be controlled by selected additives, such as gypsum, the material has remained the choice binder in the making of man‑made stones such as concrete. And what about Pozzolona Cement? Pozzolona or volcanic ash is nature’s clinker from its erupting inferno. But since its chemical composition cannot be controlled, its commercial composition cannot be controlled, its commercial viability is limited to augmenting the manufactured clinker or the ground powder, in the proportion of 10 to 30%, to form a Portland Pozzolona Cement, PPC.
In the interest of environmental safety and business common sense, fly ash from the factories themselves is used as pozzolona. But the need for the slower-setting PPC is much lower in the developed world. Consequently, OPC still accounts for over 90% of world cement production. In the Ethiopian scene, all the three operating factories predominantly produce PPC. Mesobo responded to the local demand by conducting a moderate process adjustment in 2003. Prior to that virtually all its declared output was OPC. Comparison between OPC and PPC can be made tracking three aspects: strength, setting time and cost. The short-term (seven days after setting) strength of OPC can be twice as much as that of PPC. On the other hand, the delayed setting time of PPC makes it more workable and less prone to shrinkage or cracks. PPC is ideal for plastering and block work. OPC is good where forms must be quickly stripped off the concrete. The difference in cost between OPC and PPC, in favor of the latter, is not so much because of better attributes of the former. All other things being equal, PPC and OPC will attain similar strengths in the long run. And the advantage of OPC in early strength is offset by the workability of PPC. It is the savings in energy cost due to the addition of the pozzolona that enables the manufacturer to sell PPC at a lower price than the OPC. In some applications in the USA, local codes allow the use of up to 70% fly ash to 30% Portland cement. Industrial fly ash now accounts 10% of all cement production in the USA. Considering the massive hike in fuel price and the chronically prevailing shortage of cement in the country, one wonders if it is not time to look in the direction of our deposits of volcanic ash. Not in the sense of the very limited proportion of current practice, but in the extensive approach of the Roman way. Shall we expect the production of Ethiopian Pozzolona Cement by low cost plants in the fields of Saboure? Or further down at Awash? Should none dare to risk the dormant inferno at the foothills of the Fentale?
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interview
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Ing.
. Alberto Varnero It may not be an exaggeration to say that Varnero is a household name in metropolitan Ethiopia. At least with the modern urbanite class. Certainly in the country’s construction industry whose real but sole entity the family enterprise has been until recently. Since the early 1920s and extending over three generations, Vernero has been Ethiopia’s training school, apprentice shop and master builder. In this it has left its mark on the country’s modern construction industry and building heritage for which its many historical projects are a testimony. Construction Ahead is proud in having Mr. Varnero as its distinguished guest for this issue. CA: How did it all start? AV: Varnero company started under that name in 1957 (G.C) after the split of the former Varnero Brothers Company which was founded back in 1920. The split of the old company came at the time of the construction of Africa Hall undertaken by my father Luigi Varnero. In 1964 and 1966 my brother Ermanno and I, respectively, joined the company after completion of our university studies in Italy. In 1975 all our properties and activities were nationalized except the construction company. Since 1976 we have worked, as many other companies, with ups and downs specially during the Derg regime. We worked for projects which were not undertaken by the government enterprises. It has not been so easy but we survived until free competition was restored. CA: Your construction company receives appreciation for high quality and timely project completion. How do you manage to maintain consistency considering the number of ongoing projects? AV: Thank you for the appreciation, though we also hear that we are more expensive than the others, which we do not consider true because most of our projects are taken on open tenders. It is true that the number of ongoing projects has increased in the recent past and that has required a major effort from our management and the staff to obtain good results. I believe this is, as usual, a combination of many factors: first, the dedication of our people
who have all increased their productivity in an astonishing proportion; second, the big investments made in construction equipment and machinery by the company which have been made possible by the improved general economical atmosphere but also by the investment law issued by the government, which has also contributed a lot to the growing of the construction sector. The efficiency of the company is certainly a no less important factor, but here again you have to consider that efficiency is just a way of properly utilising equipment and manpower, which themselves are a consequence of years of experience and training; they are neither the result of an overnight process nor the result of financial investment only. CA: What are the major problems encountered that may cause delays of a project? AV: I would say that the major causes of delay are divided between the three parties involved in any project (i.e., the contractor, the client, and the consultant/engineer) and the market. From the contractor: poor or insufficient contract management, delay in ordering materials in time, sites not served by adequate machinery and equipment. From the client: the continuous interference in making changes, in postponing decisions (leaving aside the case of clients who want to supply the materials by themselves with the purpose to save money avoiding the contractor’s OH&P and thus creating the most disastrous situation, to the point that our company is refusing to accept construction where this situation is stated on the tender). From the consultant/engineer: the poor quality in the preparation of many Construction Ahead, mar-apr 2006
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Dott. Ing. Alberto Varnero, was born in Asmera in 1942. After his graduation from the Istituto Bottego in Asmera in 1958, Alberto moved to Milan, Italy, to pursue his degree in engineering at the Politecnico di Milano. Just after his graduation in 1965, Alberto returned to Ethiopia and joined the family company as a junior engineer at first and then site engineer at the Hilton construction project in 1967. Strengthened by the experience acquired on the field, Alberto became the general manager of the company in 1976 at the same time managing various projects. Today, at the age of 64, Alberto still is in full charge of the company and it is not an unusual to see him walking around one of the company’s numerous project sites. His exacting demand from one and all, his commitment to his profession, company and the interest of the people working for it, his complete knowledge and understanding of everything that matters and his humble approach with all alike, make Alberto Varnero a charismatic figure for his employees who view him with awe and admiration.
projects which require from the very beginning correction for discrepancies between drawings, specifications, BOQ, etc. and the habit of many private clients to change the consultant and the engineer during the construction, using an engineer different from the consultant (which in principle is a proper decision) but without a proper prior design review. The consequence of this is a delay in the chain of decision making aggravated most of the time by the weakness of the consultant/ engineer who considers himself an employee of the client and not the third party (in between) as it should be in every contract. The market is also responsible to a limited degree (under normal situation) because it can create days of delay when cement or other materials are short on the market, but I would consider this cause as secondary. CA: Does your company always operate on its own or does it involve other companies as sub-contractors? AV: We do always work with subcontractors for specialized works: electromechanical works, air conditioning, aluminium works and others which would be impossible or at least very difficult to follow directly with the same efficiency quality and cost return. CA: Are you a member of the Ethiopian Contractors Association? If yes, what are the benefits of being a member of the association? 40
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AV: Yes. We are a member of the Contractors Association and we strongly believe that it is essential to be part of the association in order to solve general problems which cannot be dealt by a single company no matter how big that company is. CA: How has the relationship with public authorities, consultants and clients changed during your company’s life? AV: It is very difficult to make a comparison or even to remark how the relationship has changed during the years. In my opinion they have not changed, there are differences between the particular cases, but the general attitude is still the same. For instance, the feeling that the contractor, whenever he is proposing something for the good of the projects, is doing so for his own advantage, never has changed and probably never will. CA: In the construction business, disputes between the different parties involved are often inevitable. Generally speaking, what are the reasons for these disputes in the Ethiopian context? AV: As you say disputes are inevitable, but we have not experienced anything that is particular to the Ethiopian context: the most common one, dispute due to non/or delayed payment is experienced all over the world and I would say that the situation in Ethiopia is by far better than in many other countries. As for
other disputes (technical, financial or otherwise between clients and contractors), I dare say that 80% of them could be avoided if the consultants would act as I explained above as “the engineers” and not as the client’s representatives. CA: Are there possible ways to reduce the occurrence of these disputes? AV: Maybe contractors and consultants associations should get together and try to clarify the sources of conflict. CA: With the proliferation of buildings in Addis Ababa and the increase of construction companies, one major shortcoming is the lack of skilled labour. You do not seem to be affected by this. How does your company overcome this problem? AV: We do face the problem of shortage of skilled workers like everybody else. Maybe sometimes it doesn’t show because we are lucky to have continuity in the sequence of projects and a certain crew is moved directly from one project to the next. But whenever the company faces discontinuity then the problem arises for us too. Moreover, we have to say that the continuous activity of our company for the past 40 years has created a backbone of personnel that is still one of the major assets of this company. CA: Do you encounter similar problems with the managerial staff? AV: Allow me to say that our company has acted as a training centre for the past 40 years and still does this, especially when you go to skilled operators of heavy machinery or any other type of equipment. The problem with the managerial staff is even worse because freshly graduated young people (and certainly their number is not sufficient compared with the need of the country) seem not to understand that after school they still have to be trained on the job and even more difficult is the unwillingness of the great majority of them to go and work in the countryside.
CA: As a contracting company, you have to provide construction and finishing material for your projects. Are you satisfied with the availability, quality and reliability of the local suppliers? AV: Not at all, for both quality and reliability, and sometime even availability. This goes from basic items like cement, gravel and steel reinforcement to finishing materials. When we have the time, and the technical specifications are written and implemented properly, we end up in importing 80/90% of the required materials, even though they are more expensive than the locally available ones. Importers and whole sellers certainly put the low cost before quality, but I don’t think they have to be completely blamed, if the market is demanding cheap material and very rarely are the materials used in the construction checked and tested. CA: Your company often imports particular finishing materials if
required by the client. Are there any major problems with doing so? AV: No, there are no particular problems; the situation now is by far better than what we were used to in the past. CA: How does the ever increasing price of cement and steel affect contractual relationship with the client? AV: If the general conditions are properly applied the increase in these two items is covered by reimbursement. But the major problem is not the increase in cost but the unavailability of the items; and the fact that many times we are forced, in order not to stop working, to buy on the “free market�. CA: Is there anything you would change in the General Conditions of Contract presently being employed? AV: It has to be said that amendment number MI/OO 1/2004 has introduced many of the changes which I feel have been necessary,
in particular: 1) the time limit for approving and releasing payment certificates; 2) price escalation for cement, fuel, steel and bitumen, even so it should be extended to cover all materials and 3) reduction of retention money to 5%. The main problem of the Standard Conditions of Contract, as already mentioned, is the fact that the engineer should act impartially even so he is paid by the employer. This situation is never realised in practice and has been changed already in the new FIDIC conditions of contract. And again there is the clause regarding arbitration, which is now given to the Ministry of Works. This has to be changed because the Ministry does not have the technical expertise to handle arbitrations and moreover there is a conflict of interest when the case involves public works. So arbitration should be given to the Chamber of Commerce or an independent arbitration board.
The Better Machine. Authorized Distributor:
Beyo Plc.
Tel:+251 115528051/52 - Fax:+251 11 5528050 P.O.Box:550 code 1110 Addis Ababa, Ethiopia e-mail:hfp7@hotmail.com Mega Bldg. 8th floor Room No. 802
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Sun Moon and Stars By Man-Chung Tang, Dr.-Ing., P.E., Hon.M.ASCE, and Tom Ho, Ph.D., P.E. Civil Engineering Magazine
The Dagu Bridge, an innovative yet cost-effective tied-arch structure in Tianjin, China, is a kingpin in the city’s efforts to revitalize its urban core. Asymmetrical arches represent the sun and the moon, the inspiration for the design of the Dagu Bridge, in Tianjin, China, which is part of a larger effort to redevelop an older section of the city and give the region a landmark structure. The ribs vary in height—one being 19 m tall, the other 39 m—and are tilted outward, above. Each
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rib features two planes of suspenders—one at the edge of the roadway and one at the edge of the pedestrian sidewalks—allowing the ribs to be designed as slender forms, right. No piers were permitted in the Hai River because the area is known to experience seismic activity and the soils are too soft to withstand the forces that would be generated in such an event. The tied-arch bridge is supported by bored concrete piles at each abutment.
T
he Dagu Bridge spans the Hai River in the center of Tianjin, China, a city of approximately 10 million residents located about 120 km east of the capital, Beijing . The design and construction of the bridge figure prominently in the plan to redevelop and revitalize the city’s older downtown areas. For this reason, city leaders wanted a structure so striking that it would become a symbol of Tianjin . To accommodate this desire, T.Y. Lin International, of San Francisco, developed a unique tied-arch design that employs asymmetrical arches to create visual interest. Restrictions imposed by the physical characteristics of the site, together with aesthetic considerations, limited the types of bridges that could be considered. Located in an area of known seismic activity and on a site with an extremely soft top layer of soil, the bridge was to be 106 m long and more than 30 m wide and have a maximum allowable girder depth of only 1.3 m. Because of the high span-to-girder-depth ratio, a girder-type bridge was ruled out. Likewise, suspension bridges and true arch bridges were not suitable because the high horizontal forces they exert at the anchorages could not have been resisted by piles in the soft upper layer of soil. Truss and cable-stayed bridges were rejected by the owner for aesthetic reasons. Three alternatives were therefore proposed during the preliminary design stage: two self-anchored suspension bridges and a tied arch. All three satisfied navigation and design criteria. However, a self-anchored suspension bridge, although quite graceful, has a low profile and therefore would not have given the crossing the desired visibility. What is more, the city had already built some self-anchored suspension bridges and preferred a more inventive design. These factors led to the selection of a tied-arch bridge. An arch bridge can assume various forms. An arch with a single rib
was ruled out because a city bridge works better when all of its traffic lanes are adjacent to one another. Furthermore, a single-rib arch would have been too “stubby” for such a span. Therefore, it was decided that the bridge should have two arch ribs. However, the deck would be very shallow, making it impossible to place the arch ribs at the bridge’s outer edges. Instead, the ribs are located at the edge of the roadway so that the deck carrying the six vehicle lanes spans only about 24 m in the transverse direction. This configuration reduces the transverse bending moment and is much more efficient. The Hai River has been likened to a golden dragon winding through the city. For this reason, the redevelopment plan acquired a nickname that translates to “Dancing Dragon.” To complement this idea, the bridge designers envisioned a structure that would symbolize the sun, the moon, and the stars to accompany the dancing dragon. Using this concept as their starting point, the designers opted for asymmetrical arches—the larger arch for the sun, the smaller for the moon. Lighting installed along the deck’s edge would represent the stars. The final configuration is a threedimensional structure with two planes of suspenders attached to each arch rib—one at the edge of the roadway, the other at the outside edge of the pedestrian paths located on either side of the roadway. With two inclined planes of suspenders tying each arch rib to the deck, the ribs could be made very slender and still possess the required stability. In this basic structural system, the arch ribs provide the vertical stiffness for the structure, the deck provides the lateral stiffness, and the cables combine the two to form a compact system. The bridge itself is supported on piles. No piers were allowed in the river, necessitating a main span length of 106 m. With a 24 m long span Construction Ahead, mar-apr 2006
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on either side of the main span, the bridge’s total length is 154 m. The bridge carries six lanes of traffic and two pedestrian paths. Two of the traffic lanes are 3.75 m wide, and the other four are 3.5 m wide. The minimum width of each pedestrian path is 3 m. With its median divider, barriers, and railings, the deck has a minimum width of about 30 m. For a 106 m long span, arch ribs normally would reach heights of roughly 20 m. To introduce an element of surprise into the architecture, the two arch ribs differ in height—one rising 19 m, the other 39 m—and they also incline outward. In most arch bridges, the arches are vertical or incline inward. The outward inclination of the arches gives passengers on the bridge a distinct feeling of openness. To further add to the architectural interest, the pedestrian paths curve outward so that those on foot have additional space in which to rest and enjoy the surroundings. And because the immediately surrounding area is to be developed into a recreation and entertainment district, space that enables pedestrians to enjoy the view is a welcome feature. From a geotechnical standpoint, a tied-arch bridge is well suited to the location. The site’s soft clay has a poor bearing capacity, and a tied arch is one of only a few bridge types that can readily accommodate such conditions. The bridge superstructure is supported by bored concrete piles. There are 16 piles at each abutment, each 1 m in diameter and 35 m long. There are also 16 piles at each of the two main piers, but these are 1.2 m in diameter and 58 m long. As long as the piles retain their vertical load capacity, they can bend in any direction and the bridge will remain stable. The stiff deck girder can redistribute horizontal forces among the piles under all conditions. The superstructure had to be designed in such a way that it would not become unstable if seismic activity caused excessive horizontal movement at the supports. Tianjin is approximately 100 km from Tangshan, the scene of a massive earthquake in 1976 that caused extensive damage and killed hundreds of thousands of people. Consequently, the Dagu Bridge was designed for the highest class of seismic forces in China, a level that would be comparable to seismic zone 4 in the United States . The design speed for vehicles traversing this urban bridge is 60 km/h. The live load used to design the structure was the Chinese city class A loading, which equates to a five-axle truck with axle loadings of 60, 140, 140, 200, and 160 kN. A three-dimensional nonlinear analysis for both static and dynamic loads was conducted as part of the structure’s design. The bridge behaves basically linearly up to an overload equal to about 400 percent of the total load, defined as all permanent loads plus full live load, on the bridge deck. This far exceeds the factor of safety required for such structures. The bridge girder is divided into three parts, each of which is a steel box section. The 24 m wide center box supports the six lanes of traffic. The two other boxes vary in width and carry pedestrian loads only. Open spaces were included between the boxes for aesthetic reasons and to separate pedestrians from vehicular traffic on the bridge. The three boxes are transversely connected by crossbeams that extend horizontally through all the boxes. The suspenders from the ribs are attached directly to the crossbeams. The deck’s maximum allowable vertical slope is 3.5 percent. Because of this limitation and navigation requirements, the girder depth cannot exceed 1.38 m at the bridge’s centerline. A 2 percent transverse slope further reduces girder depth to 1.3 m at the edge of the traffic lanes. 44
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Obviously, the bridge could have been constructed of steel or concrete. In fact, a concrete bridge would probably have cost slightly less. However, any savings would have been insignificant because of the seismic requirements. A concrete bridge would also have been much heavier and less desirable aesthetically. China now produces its own steel, which is comparable in quality and strength to steel used in the United States . Because China builds a tremendous number of steel bridges every year, most steel fabricators now fabricate quality components for steel bridges. Labor costs are also relatively reasonable. For these reasons, the decision was made to design the Dagu Bridge as a steel structure. In terms of steel used on the project, the box girder employed roughly 3,000 Mg, and the arch ribs required approximately 450 Mg. As a result, the bridge has an average steel weight of approximately 0.61 Mg per square meter of usable deck area. The steel boxes all feature orthotropic (orthogonal anisotropic) decks. A deck plate thicker than usual—16 mm, with 8 mm thick U ribs under the traffic lanes—was used. Floor beams are spaced 4.0 m apart. The traffic lanes have a 50 mm thick epoxy asphalt pavement. A 16 mm thick deck plate was selected for the traffic lanes because a large volume of heavy truck traffic is anticipated as the area develops. Experience has shown that a thicker deck plate significantly improves the service life of an orthotropic deck and the pavement. Consequently, a thicker deck plate was seen as more appropriate. The epoxy asphalt was imported from the United States . The two steel arch ribs differ in more than just height. Although both are trapezoidal and have a constant soffit width of 0.9 m, they have different inclinations and different dimensions. For the large rib, the width of the top plate varies from 1.3 m at the crown to 2.2 m at either end, and the depth varies proportionally from 1.3 to 2.2 m. For the small rib, the top plate is 1.3 m wide and the depth is 1.3 m along the entire length. The sides of the ribs maintain a constant slope, a feature that facilitated fabrication. The walls of the hollow ribs vary in thickness from 40 to 60 mm. Diaphragms within the boxes are spaced at horizontal intervals of 4 m. Although the trapezoidal shape was selected primarily for aesthetic reasons, concerns about fabrication also influenced the decision. In the view of the bridge’s designers, a rib in the shape of a trapezoid has more character than a round arch rib. What is more, a trapezoidal rib is much easier Construction Ahead, mar-apr 2006
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to fabricate. This shape also lends itself well to lighting. Spotlights installed at the deck level illuminate the soffits and both sides of the ribs as well as the suspenders. To eliminate costly maintenance, no lights were installed on the arch. Both arch ribs are distinguished by a parabolic shape. Because most of the load comes from the deck and this load is basically uniform, the parabola is an appropriate shape. It is also a more elegant form for this structure. The slightly nonuniform dead load causes a small bending moment in the arch ribs under permanent loading. However, the magnitude of this bending moment is not significant. Approximately 75 mm in diameter, the suspenders comprise parallel wire strands that are held in place by HiAm type anchorages (from BBR VT, International Ltd., Schwerzenbach, Switzerland), which employ a tapered socket filled with epoxy, zinc powder, and small steel balls. The wires are 5 mm in diameter and have a tensile strength of 1,670 MPa. They are button headed and are anchored at a plate near the end of the socket. A white sheath of high-density polyethylene (HDPE) was extruded over the parallel wire bundle to provide protection and impart the desired color. The suspenders are designed in the same way as 46
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the stays in a cable-stayed bridge and in accordance with the same safety factor and quality control requirements. The suspenders connect to the arch ribs at the diaphragms and to the deck at the crossbeams. To help ensure safety and facilitate maintenance, the deck, like those on cable-stayed bridges, has been designed so that a suspender can be replaced without interrupting traffic. The arch ribs are rigidly connected to the steel box girder at both ends of the main span. Therefore, the bridge girder can serve as the tie of the arch ribs. However, additional ties were provided to increase the redundancy of the structural system. These ties were placed inside the central box girder and anchored to enlarged transverse steel box beams located over the piers at both ends of the main span. Since the ties were prestressed to predetermined forces, the longitudinal components of the arch ribs are significantly balanced by the tie forces. Because the two arches are of different heights but carry approximately the same loads, the tie forces of the two arches are not the same. Since the taller arch is about twice as high as the other, its tie force is only half as great. The steel box girder will not experience high tension under the permanent load condition.
The steel girder and the ties by themselves are sufficient to resist horizontal forces from the arch ribs, making the system inherently redundant and safe. Individually sheathed tendons comprising seven-wire strands are used as ties. They are placed inside a larger polyethylene duct located within the middle steel box. The ties are anchored at a 2 m deep transverse girder at both ends inside the box girder. The arch ribs are connected to the same transverse girder so the tie force will be transferred between the ties and the arch ribs. Because of the much higher stiffness of the steel box girder, the ties do not experience any noticeable stress variations under live loads and therefore are not susceptible to fatigue. Because the box girder alone can act as the tie, the strands can, if necessary, be replaced individually without interrupting traffic. During conceptual design, an extensive study was conducted to determine the best color for the bridge. Finally, a particular shade of white was selected, and the cables also were to be white. However, the members in the openings were to be dark gray to provide a clear contrast and to augment the sharpness of the bridge’s configuration. The bridge’s illumination comes from three sources, the first being streetlights on the bridge and along the riverbanks. The height of the light posts was minimized so as not to block views of the arches. Small lights were installed at the posts of the pedestrian railing so that those on foot would not have to deal with glare. Spotlights situated on each suspender at a level slightly below the deck constitute the second source of light. Two spotlights are employed at each suspender location to provide a more uniform reflection on the arch ribs. These lights illuminate the arches and all of the cables. Color filters can be installed on these lights so that different colors are available for special occasions. Finally, lights
under the edge of the outer rim of the pedestrian paths are the third source. These lights shine downward to the water and horizontally through the holes in the edge plates. The three light sources are well coordinated to give the structure a graceful, elegant appearance at night. Because the Hai River currently experiences little marine traffic, temporary supports could be placed in the river for construction. The entire bridge was erected on traditional falsework, the lower tier of which was supported by piles driven into the riverbed. Box girders were delivered to the site in sections and welded together on top of the falsework. Steel beams connecting the three lines of box girders were made continuous after the box sections had been completed. After the deck was finished, another set of falsework was erected on top of the deck girder to support the arch ribs. The falsework comprised patented universal elements that could be rapidly assembled. The arch ribs were divided into 4 m long sections and welded together on top of the falsework. The suspenders were installed after the arch ribs had been completed. The inner layers of suspenders used to connect the edges of the central box and the arch ribs were partially stressed before the falsework was lowered and removed. The stressing came from a set of forces just sufficient to stabilize the arch ribs without falsework support. The final stressing was conducted in stages to attain the predetermined stress distribution in the structure. The construction method using falsework is very simple and straightforward. The universal steel elements employed for the falsework are reusable and can be easily assembled and disassembled. This method also significantly simplified geometry control during erection. The lighting fixtures were installed after the bridge structure was completed. Because lighting was considered during the preliminary design stage, the locations of all light fixtures were established at an early point. Construction of the bridge began in the fall of 2003 and was completed by the end of 2004. All told, design and construction required only 22 months. Standing as a symbol of the revitalized Tianjin, the bridge is open to traffic and admired by residents and tourists alike. A successful bridge must be safe, functional, artistically engaging, and economical. The Dagu Bridge meets all of these criteria. Construction of the bridge cost UsD11.5 million, which equates to approximately USD 2,000 per square meter of net usable deck area, or USD 1,400 per square meter of gross deck area. This proves that a beautiful bridge need not be expensive.
UPF SHUTTERS
High quality first grade PVC 6 colors available Full range of accessories Guaranteed against UV rays
Universal Plastic Factory plc Tel 00251 11 6616005, 6293416 Fax 00251 11 6293444 P.o.Box 80030 Addis Ababa, Ethiopia universal.plastic@ethionet.et Construction Ahead, mar-apr 2006
47
opinion
By: G.Kassa (structural Engineer)
O
k! So Addis is growing - at least we seem to think so with the countless buildings rising like vital signs to a perfectly healthy heartbeat. That is good, right? Not that I am complaining but with the current ridiculous escalation in cement prices, I wonder how long the trend will sustain. In the hopes of satisfying this demand, an unprecedented number of investors have acquired licenses to invest in cement factories. But I seriously doubt if they will come around in time to keep the construction momentum going strong. With the current rate at which we are building, it wont be long before we ran out of cement. This brings me to my point. Whatever happened to alternatives? We Ethiopians have this thing I prefer to call the “Mexican Wave”. When one individual starts up something the rest just blindly follow suit. We rarely stop to think if there are any feasible alternatives. We desperately want for example, our new ground plus to look just like the one Ato X just finished building. So basically when the wind blows west, we all blow west and continue to do so until the trend changes - just like 48
Construction Ahead, mar-apr 2006
the famous Mexican wave in many football stadiums. This wave is so prevalent in a lot of fields these days that I have just had enough of it. The clients come to the architect requesting a house that looks like his/her neighbour’s and that is exactly what they will get. Hence, transforming the Addis skyline into one big “Deja Vu”. How many recent steel buildings have you seen in Addis? I don’t know about many of you but Shoa Supermarket is the lonely structure that comes to mind at the time of writing of this opinion. I admit I am no expert at this but I seriously think steel has now become a feasible alternative in Ethiopia with the additional advantages of speed of construction and a reduction in superstructure weight. I believe that we are deeply entrenched in the “traditional practice” of designing concrete structures that we have just turned a blind eye to other alternatives. Our engineers have developed these Microsoft Excel templates through repeated and monotonous use and they simply frown upon any design that makes them relinquish this programmable number crunching
software. I am sure our engineers and architects are trained to shape and design more than concrete and reinforcement but I seriously doubt if anybody is audacious enough to think outside the box and come up with something if not truly revolutionary at least creative and innovative enough. I hear many architects complain that the reason for redundancy of design is because of the clients’ requests. But on the other hand the duty of the “consulting firm” is to propose different designs and guide clients in their choice. It seems all that everybody does these days is construct a building and rent out office space with the ground floor space reserved for pastry shops or supermarkets. Hence all you can do in Addis these days is work, eat and sleep-no theme parks, roller coasters-nothing! I think it is bad enough that we have adopted almost all of our architectural designs from the outside world, let alone steal designs that have already been stolen. I once heard someone say If you are going to make mistakes, at least make new ones.
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www.ab-ham.com
product advertising
Thixotropic cold applied non-ionic bitumen emulsion (fibrated & non-fibrated)
POLYCOAT non-Ionic are water based bitumen coating manufactured to comply with ASTM D 1227 type 11, class 1 (Fibrated) and type 111 class 1 (Non fibrated). Fibrated emulsion is mixed with special reinforcing fibers for additional stability. The coating is dark brown in color and dries to a black flexible protective film. The finished films are tough and forms a barrier to water and vapor transmission.
TECHNICAL DATA Properties
50
Fibered
Non Fibered
Test
Min
Max
Min
Max
Method
Weight per litre, gms
980
1080
980
1040
ASTM D 2939
Residue by evaporation
45
55
47
53
ASTM D 2939
Water Content %
-
55
-
53
ASTM D 244
Firm Set, hours
-
24
-
24
ASTM D 2939
Construction Ahead, mar-apr 2006
USES Polycoat non-ionic emulsions are general waterproofing and damproofing material that adhere to a wide range of surfaces including concrete, metal, wood etc. They can be used as the protective coating for built-up roofing systems and other exposed surfaces, as a damp proofing membrane or as vapour seal. For vertical and steep sloping surfaces the fibrated emulsion is suitable while the non-fibrated is ideal for horizontal surfaces and slopes up to 450. These emulsions are suitable for service temperature 100C to 850C. APPLICATIONS AND INSTRUCTIONS Ensure that surface to be treated is sound and free from all oil, grease and other foreign matters. If the surface is dusty, it should be primed with the same emulsion diluted with 20% water and allowed to dry. Emulsion has to be thoroughly stirred before use. It can be applied by brush broom or squeegee. COVERAGE Apply at a rate of 1.1 litre/m2 to get 0.6mm(Non fibrated) and at a rate of 1.3 litre/m2 to get 0.7mm (fibrated) dry film on concrete surfaces. Apply the second coat at the same rate. The first coat must be dry before applying the second coat. Coverage depends on the smoothness and porosity of the susbstrate and required thickness of coat.
FEATURES • Resist the attack of salts that present in the soil and underground water. • Easy to apply • Cold applied • Adheres to concrete, wood, cork,etc
metal,
• Non- flammable • Versatile • Economical • Conforms to ASTM D 1227
PGA Tech Plc., established in January 2002, has become a major supplier of irrigation and construction materials throughout the country. At the moment, PGA Tech carries in its stock construction materials such as geotextile, materials to stop soil erosion, an array of waterproofing materials, additives and admixtures, an array of drainage accessories, fountains equipment and accessories, nets for construction, irrigation and home use, and many other novelty products which are presently being used in Europe.
STORAGE Store under cover, out of direct sunlight and protect from extreme temperatures. Shelf life is upto 12 months when stored as above. Failure to comply with the recommended storage conditions may result in premature deterioration of the product.
For further enquiries contact:
PACKING Polycoat is available in 15-litre Pails & 200-litre drums. HEALTH AND SAFETY P O L Y B I T
As with all Bitumen products, caution should always be exercised. Protective clothing such as Gloves and goggles should be worn. Treat any splashes to the skin or eyes with fresh water immediately. Should any of the products be accidental Swollen, do not induce vomiting, but call for medical assistance immediately.and required thickness of coat.
Sole authorized distributor in Ethiopia
Tel. Off 011 6636671 Fax/Tel 011 6623548 P.O.Box 27101 Addis Ababa, Ethiopia E-mail: pgatech@ethionet.et
Construction Ahead, mar-apr 2006
51
technology
source: Detail English Edition
“T
he UFO has landed” - this was the headline used by some newspapers on the day of the opening of the Allianz Arena, and when looking at the stadium, one does indeed have the feeling that one is standing in front of something »extraterrestrial«. The world’s largest membrane envelope stretches around the new stadium and is made up of 2,874 cushions, covering an area of 64,000 m². The so-called »pneus« were manufactured by covertex out of 0.2 mm thick ETFE foil, which on the roof area is transparent and on the remaining areas of the facade translucent. The edge lengths vary between 4 and 8 m with spans of between 2 and 4.25 m. Blowers inflate the cushions and pressure load cells ensure the correct pressure compensation, including when one of the »pneus« leaks. As there are only ever two cushions of the same size, the whole facade required a total of 1437 different cushion sizes to be manufactured,
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with the service life of the nonflammable but extremely cold and heat-resistant cushions being 25 years. Installation required the use of professionals, and up to 60 industrial climbers from the company Membranteam in Ravensburg worked on the façade at the same time using a net and double floor. While it was possible to walk on the primary structure of the roof using planks and safety harnesses, the secondary construction, required for the installation of the cushions, had to be fitted out with »walk nets« which fitters could then walk along like on trampolines. The envelope is impressive by day, but it is by night, however, that the Allianz Arena can be seen in its full glory. It is so bright, so luminous, and so impressive that serious consideration was given to installing screens so as to hide it from the adjacent highway and thereby
minimize the risk of accidents. The light, airy nature of the membrane construction is a prerequisite for the illumination. Each air cushion contains four specially-developed Siteco lights, and red, blue, and transparent covering panes allow spectacular colour changes to take place. Parabolic reflectors, specially developed for these lamps, ensure uniform illumination, with a total area of 24,000 m² illuminated. The intensity with which the lighting can match the drama of the game is almost equal to that of a pulsating organism. This is because the architects believe: »architecture must be a sensual and intelligent medium - otherwise it is boring«. There is certainly no danger of the Allianz Arena being boring, with the stadium also being referred to as the »witches’cauldron«. One reason for this is no doubt the fact that it features the steepest seats in Europe, 66,000 in total, specially designed by Herzog & de Meuron. A suspended ceiling strengthens the cauldron atmosphere, with the steel construction of the roof covered by large, trapeziform solar paddles that can be retracted completely under the transparent cushions in order to allow through the UV light that is needed for the pitch - also manufactured by membrane specialists covertex.
Mobile batching plant
M
ek-Tek Ltd has introduced a range of mobile batching plants (MBP) capable of providing continuous on‑site production of concrete or screed. They are available in 6, 8 and 10 m³ mix capacities and work at rates of up to 60 m³/hr, with single loads down to 1/4 m³. As well as compartmentalised storage for aggregate, sand and cement, 2100 liters of water is carried on-board, together with provision for both high and low flow liquid admix systems. Additional liquid and powder dispensing is also available. Load mixing is carried out on-site, adjacent to
the point of use, with individual mixes subject to the inclusion of fibres, powders or liquids where required to achieve the necessary strength, structural properties or even colours required for each load. The MBP vehicle can also be driven while mixing, enabling continuous back-fill trenching or post holing work to be carried out economically, says Mek-Tek. Drive options range from the conventional PTO, with the preferred option being a dedicated donkey engine for load mixing and running the hydraulics. The donkey engine ensures maximum life and minimum strain on the chassis engine. The MBP is also equipped with a fully guarded rear safety platform which provides the operator with a viewing station during loading of the dry constituents, thus eliminating the possibility of cross contamination and meeting one of the main prerequisites of compliance with QSRMC. The MBP is fitted with a key safety interlock system, which fully isolates the main mixing auger, when the unit is being cleaned via a full-length trough opening. According to Mek-Tek, load dispensing via the remote pendant control can be carried out from within the vehicle cab or from the rear of the vehicle at up to 4 m distance. Although equipped with a single 1 m extension chute as standard, further 1 m extensions are available on request for extended material placement requirements.
Made in Germany
THEY STAY WITH YOU THROUGH THICK AND THIN. Metabo offers you one of the most comprehensive ranges of electrical tools. With our 200 different devices you can certainly get the optimum solution for your area of use. Metabo comes with six month warranty and assured repair and replacement within 24 hours.
SUTC
plc
Tel 551 27 58, Fax 551 50 82 sutco@ethionet.et Wollo Sefer opposite Ibex Hotel
Surveying Equipment Multipurpose rotational lasers The Mikrofyn ML 10‑15 lasers can be used for just about any need. They can function as automatic self-leveling lasers, semi-automatic dual grade laser, or for machine control, along with many other purposes. Operators can select the rotation speed. The lasers are built to be strong and robust, and are housed in their own “crash helmets.”
Lasers for large-scale projects
What we know that you don’t Just about everything you’ll ever need to know about building products and services! SPECIFY is the single most important source of information for architects, builders, consulting engineers, quantity surveyors- in fact anyone responsible for specifying products and services used by the building industry in Ethiopia. SPECIFY Building Product Information Catalogue, is constantly updated with the latest information regarding: manufacturers’ product data, detailed specifications, in- depth how-to-use designs, illustrations, photographs, samples and color swatches, fixing details and creative building ideas. More important, SPECIFY has now gone digital. The same building and service information you get in the Catalogue can be accessed on the Internet at www.specifyethiopia. com. The digital version takes advantage of the Internet technology and provides you with several additional services; such as news, bids, links to a variety of resources and easy updates of listed catalogue materials. If you’re not already using SPECIFY in your office it will pay you to find out how it can save you time and money. For further information call: 0115-
515787
Or visit: www.specifyethiopia.com
Your quick and easy access to a world of building product information.
The RT-5SW is a new long-range, dual-slope laser for large-scale earthmoving operations. It features remote control that enables operation from distances up to 1000 feet, yet it still retains five-arc-second accuracy. It also includes the SmartLine automatic guide alignment system, and an automatic grade-matching feature for faster and more accurate work.
For next-generation grade control The MS990 Smart Antenna for satellite positioning tracks next generation GPS L2C and L5 signals, as well as GLONASS, so contractors can work at longer ranges with faster initialization times. The positioning sensor works with the GCS900 3D Grade Control System, which gives earthmoving contractors a common platform across their fleet, while allowing them to select the best option for the machine and application.
Electronic level has new capabilities The Sprinter 100M electronic level now features new line-leveling capabilities covering most of the common field leveling procedures. The new onboard commands facilitate two-way communication between the instrument and the PDA or data collector.
Grading and excavation lasers The new Pro Shot AS2 and AS2 Magnum lasers are designed for grading and excavation contractors who need slope capability, long range, and high accuracy. Upgraded electronics provide better performance, improved battery life, and easier use. A redesigned base replaces the cast-metal base for a sleeker look and better access to the grade knob.
CHROMIX Admixtures.
A
ward winning projects begin with award winning materials. CHROMIX[R] Admixtures for Color‑Conditioned[TM] Concrete are colored, water‑reducing, set‑controlling admixtures for ready mixed architectural concrete. Coloring concrete integrally, they produce rich hardscapes and precast, tilt-up, or cast-in-place buildings of enduring beauty. CHROMIX Admixtures provide permanent, streak-free color conditioning, and increased concrete strength at all ages. CHROMIX Admixtures are available in two convenient forms: The original CHROMIX P (powder) and new CHROMIX L (liquid). Both offer maximum design and construction flexibility. The total CHROMIX engineered system delivers reliable, streak-free colorconditioning and performance characteristics superior to concrete colored by raw pigments.
Decor Collection
T
he *ED 16. door, designed by Bartoli Design, is Laurameroni’s first proposal for its new Decor collection. The door is no longer conceived as an object-funciion but as a distinctive element that increases the value of the place in which it is situated. It has the same surface treatment as the sBD14. and the uBD15. sideboards that belong to the .Maxima. collection. The door is available as a sliding or hanging version and is made to measure according to the dimensions and wood essences chosen by the customer. Particular attention has been paid to the execution of the cladding, which provides for quick assembly without any visible fastening screws. www.laurameroni.com
An Italian company has begun marketing a cement that is capable of absorbing pollution from vehicles
I
talcementi, which spent 10 years developing its TX Active, said the building material is capable of reducing urban pollution by more than 40 percent, the Italian news agency ANSA reported. Tests on a road near Milan showed TX Active cut the level of nitrogen dioxide and carbon monoxide by as much as 65 percent. It functions via a chemical process called photocatalysis, whereby sunlight triggers a chemical reaction when titanium dioxide on the surface of the cement comes into contact with pollutants in the air. TX Active works most effectively in bright sunlight. Italcementi said test results have been verified by independent bodies like the Italian National Research Council. TX Active cement has already been used on a number of buildings, including Air France’s new headquarters at Paris’ Charles de Gaulle Airport, Rome’s Dives in Misericordia church and Bordeaux’s Hotel de Police. United Press International Construction Ahead, mar-apr 2006
55
software review
Bricks and Clicks Building may become even higher-tech, with projects ‘finishing’ on-screen before construction starts
T
he construction industry is a world apart from the computer games business, but that could be about to change: planners, designers and builders will be able to work together using the same kind of ‘virtual environment’ in which internet gamers compete against each other in cyberspace. Researchers are combining game and CAD (computeraided design) technology to create three-dimensional environments in which professionals, working in real time, will be able to explore and test ideas for new buildings. This ‘Virtual Worlds’ project is being undertaken by the Cooperative Research Centre (CRC) for Construction Innovation, involving CSIRO’s Division of Manufacturing and Infrastructure Technology (CMIT). The CRC for Construction Innovation is a national research, development and implementation centre focussed on the needs of the Australian property, design, construction and facility management industry. It undertakes applied research on behalf of its partners and the whole industry. 56
Construction Ahead, mar-apr 2006
“The goal of the Virtual Worlds project is to use game technology to visualise construction projects in the form of an interactive 3D environment,” says Professor Keith Hampson, chief executive officer of the CRC for Construction Innovation. CMIT’s Stephen Egan says many scenarios would benefit from this novel approach, such as urban planners being able to visualise every aspect of an entire development: “The associated plans could be studied interactively by planners, builders, suppliers, residents, even traffic authorities or environmentalists. Collaboratively, they can use the latest software to optimise the quality and functionality of the development, or the sustainability and its lifecycle performance.” The Virtual Worlds project is headed by Professor Mary Lou Maher of the University of Sydney, who has studied how people behave in virtual environments. She says groups working virtually do not suffer the same inertia as committees, and will produce better built environments. “Research shows that
people actually brainstorm significantly better when working collaboratively in cyberspace,” she says. And helping people with diverse viewpoints to get along is no mean feat. She says there is less sense of hierarchy among collaborators and an increase in ‘open space’ creativity. “Factors such as accents or reluctance to speak up disappear, ensuring more ideas are expressed. Best of all, verbose individuals can’t stall proceedings with their prolonged soliloquies.” Parallel streams of ideas are standard in these environments as are video-stream records of proceedings. Normally, concepts such as meshing CAD tools and construction assessment software with virtual environment technology and collaborative theory would be considered far-fetched, or at least something for the distant future. However, Australia just happens to have the scientists who are at the vanguard of this work. Australia leads international efforts to establish standardised data structures to promote interoperability; the Industry Foundation Classes (IFC) already developed have allowed a CSIRO Future Cities team led by Robin Drogemuller to generate a suite of software packages that are pushing the limits on design science. To realise the scenarios sketched out by CSIRO’s Stephen Egan, the researchers really only need to develop a way to import existing software models as IFC files into the Virtual Worlds format. Then the whole suite of applications – such as ArchiCAD and the CRC’s LCADesign – will come on line in 3D splendour. The research is still in the experimental stages but, significantly, it is working. Objects that mean different things to the architect, builder, supplier, resident, neighbour and city planner can be visualised within the same easily accessed space. Collaborative brainstorming is then further aided by Australian software that can assess different designs relative to the lifecycle performance of buildings or infrastructure. Being able to visualise answers can transform the impossible into the plausible, the preferred and the actualised. The researchers working on this believe they are on the threshold of major gains in data visualisation technology, leading to a step-change in the visionary capabilities of human ingenuity.
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Alta Computec Authorized Distributor for Ethiopia Tel 553 20 40, 550 29 29, 550 29 28 P.O.Box 12301, Addis Abeba, Ethiopia alta@ethionet.et
e-COL Introducing e-COL, a concrete column design software package capable of designing concrete columns with sway conditions or braced/non-sway columns.
J
ust like in all other projects, first you do the modelling and actual structural analysis. Sorry, there are no short-cuts to this yet. Then you select the columns to be designed and generate the analysis data to be later imported to e-COL for column design. The software also imports the member ID along with the other information so you don’t have to worry about keeping track of the different column names and designations. e-COL supports analysis results from SAP2000 and ETABS but you have to install different versions of the software depending on your specific analysis software. Before getting down to the actual designing, you specify the section properties of the column on Excel type input tables by clicking on “column” under the “Define” tab. The different parameters to be entered include the width and height of the column crosssection, the number of bars in the two orthogonal directions, concrete and steel properties and the effective length of reinforcement. A preview window updates itself as you enter along the data and we have found this to be really cool. You then go to the Define tab again and click on “Moments”. Options considered are from eccentricity or any other source. The last step would be to specify the location of the input data which you generated earlier either from SAP2000 or ETABS and then you are ready to design. Just click on the “Design” tab or the little triangle icon just like in SAP2000. You will be prompted to save your work, which you really should because e-COL can’t analyze your data until you do so. After a only few seconds of number crunching, what you have on your screen is the finalized design details of your column(s) with reinforcement area, column type and enough data for an impressive design report (static book). The output is displayed in graphical as well as tabular form including interaction charts, calculated area of steel for all load combinations, details of the 58
Construction Ahead, mar-apr 2006
non-dimensional design constants and omega. Your design data can also be copied to an Excel spreadsheet for further editing. e-COL makes it easier to play around with different cross-sections and reinforcements to come up with an optimum design. In case your column fails or becomes too slender, e-COL displays a “fail” message on the resulting output. You also have options of viewing only the critical data to be used for design. One question you might ask yourself here is, can it do circular columns. Well, we hate to disappoint you but no! The section properties window only accepts width and length parameters and there is no room for radii. We also thought the idea of clicking on the “define” tab at least three times in trying to design the columns was such a drag, when you could have simply fit everything onto one entry table. We have also noticed that there are no written help files associated with the program. e-COL is another product from e-Team (the company that brought you StructCAD). Column design has been a challenge for our engineers since most state‑of‑the‑art design programs do not incorporate Ethiopian design codes; and the several load combinations required for building design, coupled with the interaction of axial loads with biaxial moments make column design a tedious task. With a lot of Excel templates out there for attempting to design columns, we think, e-COL is one very big step closer to actually automating the entire process. As much fun as it has been reviewing local engineering software made by Ethiopians, we have sadly come to the last, but not in any way the least, software on our short list. We therefore look to our dear readers to recommend any software products developed by Ethiopians directly related to the construction industry and not yet covered by us.
Survey
Engineers and scientists still rely on hand calculations
SIEMON
TM
COPPER / FIBRE CABLING SOLUTIONS
Maplesoft reports that mathematical work is still often performed with paper and pencil Maplesoft, a developer of advanced mathematical and analytical software, announced recently that mathematical calculations in engineering and academia are still most often performed with pencil and paper, according to the company’s international survey. On a daily basis, respondents turn to scratch pads and calculators more frequently than any other tool for mathematical tasks. The same survey also revealed this community largely considers its field of work and study as both modern and taking full advantage of modern tools and technology. The study results are drawn from an international survey of scientists, engineers and researchers across a variety of diciplines, including aerospace, automotive, electronics, telecommunications, pharmaceutical, life sciences, finance and education. With more than 2,000 participants, the survey offers insight into the daily practices, experiences and perceptions of the technical user community, the company reports. When questioned about how frequently they used a range of tools and resources for design and analysis: 52% of respondents indicated that they use hand calculations (calculators) and paper daily, with an additional 21% citing it as a weekly practice; 47% indicated that the next most common resources used daily are electronic references and tables (for example, CD-ROM, the Web), with another 26% using them weekly; 35% indicated that they use print reference books and tables daily, with another 31% using them weekly; and 39% indicated daily use of spreadsheets, which remain the most common software tool used in analysis and design. Another 31% of users employ them weekly. “It is startling to see such hard data revealing the continued reliance on tools and practices that require so much manual effort and leave so much room for error,” says Jim Cooper, CEO of Maplesoft. “This is a user base that is charged with driving innovation, exploring the cutting edge and bringing the best new products and services to market and yet, to a large extent, they are holding onto outdated and outmoded practices. So much of their important work will remain locked in their notebooks and lost to the layers of their spreadsheets rather than captured and carried forward with all of their logic and thinking documented.” The Maplesoft survey was open to all engineering professionals, including design engineers, research scientists, field engineers, project managers, consultants and educators. From December 2005 to February 2006, 2,092 participants from the United States, Canada, Germany, the United Kingdom and Japan filled out the online questionnaire covering collaboration and communication, design and analysis tools and overall perception of the design environment
Siemon offers the most comprehensve product set in the IT industry. Siemon can build a solution for any enterprise application and need of today and tomorrow.
Alta Computec
Authorized Distributor and Service Provider Tel 553 20 40, 550 29 29, 550 29 28 P.O.Box 12301, Addis Abeba, Ethiopia alta@ethionet.et
books
Modern Comfort by Katherine Sorrell
Asian Elements: Natural Balance in Eastern Living by Jane Edwards
Applied Statistics for Engineers and Scientists by Jay L. Devore, Nicholas R. Farnum
T
his concise book, for engineering and science students, emphasizes modern
statistical methodology and data analysis. APPLIED STATISTICS FOR ENGINEERS AND SCIENTISTS is ideal for one-term courses that cover probability only to the extent that it is needed for inference. The authors emphasize application of methods to real problems, with real examples throughout. The text is designed to meet ABET standards and has been updated to reflect the most current methodology and practice.
M
odern Comfort is a source book of contemporary decorating that promises a new modernity in which comfort is to the fore. From wall and floor coverings, to furniture, fabrics, lighting and storage, it highlights a range of design ideas for every room, with the emphasis on creating a home that is in tune with the way we live today. Streamlined modern aesthetics is apparent in the emphasis on the clean shapes of furniture, well thought-out storage, understated color schemes and a consistency of materials throughout a space. But, while there are stainlesssteel worktops, tiled walls and glass panels, comfort is ever present too-the natural tone of wood and sisal, seating that is plump and inviting, cozy wool blankets and soft, textured linens. It is this combination of cool with a softened edge that creates that look and signals a less rigorous more realistic style of interior. Adaptability and ease are essential ingredients. These are spaces that are attractive but also practical, and very much for living in.
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all books are available at
Electricity, Electronics, and Control Systems for HVAC by Thomas E. Kissell
D
rawing from the author’s 20+ years of professional and academic experience, this book presents basic AC and DC electricity, electrical principles, electric circuits and controls for air conditioning, heating and refrigeration systems. It is specifically designed to be clear and concise enough for beginners—with a straightforward writing style and numerous diagrams and illustrations— yet comprehensive and accessible enough to serve as a professional reference. Chapter topics include safety; tools for HVAC technicians; fundamentals of electricity and electrical meters; series circuits; parallel and series-parallel circuits; magnetic theory; fundamentals of AC electricity; transformers, three-phase, and single-phase voltage; symbols and diagrams for HVAC and refrigeration systems; relays, contactors, and solenoids; single-phase open motors; single-phase hermetic compressors; threephase open motors and three-phase hermetic compressors; motor starters and over current controls; thermostats and heating controls; pressure controls, timer controls, and other controls; electronic devices for HVAC systems; electrical control of heating and air-conditioning systems; electrical control of heat pump and refrigeration systems; and direct digital control systems. For service technicians, HVAC technicians, contractors, and HVAC installers.
Trigonometry by Charles P. McKeague
T
his text provides students with a solid understanding of the definitions and principles of trigonometry and their application to problem solving. Identities are introduced early in Chapter They are reviewed often and are then covered in more detail in Chapter 5. Also, exact values of the trigonometric functions are emphasized throughout the textbook. There are numerous calculator notes placed throughout the text.
Book World is a division of Shama Plc. Outlets: Piassa 011-1559013 Bole Friendship 011-6639912/13 Zerihun 011-6636395 Sar Bet 011-3724574/75 ECA 011-5444103 Hilton News Stand 011-5518400 Hilton World Shop 011-5518400 Ext. 840 Sheraton Premium Shop 011-5173698
Shama Plc Tel. 011-1556200 P.O.Box 8153 Addis Ababa, Ethiopia
snapshot
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Construction Ahead, mar-apr 2006
Not every picture is worth a thousand words. And there may be some that are worth more. We hope ours fall at least somewhere in between. In any case, we want to end Construction Ahead with a photograph that we hope will always be interesting enough and constructive. So, if you have an unusual picture, that attempts to capture an intriguing coincidence of space and time, do send to it and share it with our readers. Sorry, but we will not be able to return submitted photographs but appropriate credit will be made.
Construction Ahead Website www.constructionahead.com
The Magazine and its associated web site complement each other in their coverage of the whole gamut of the industry, each taking advantage of its particular medium. Whereas the magazine is better suited for reviews of new construction technology techniques and tools, you need to log into the more interactive and constantly updated web site to get the latest prices for building materials and projects being tendered. But the Web site has much more. It does give a synopsis of the magazine plus: Discussions Forums under three categories; technical (addressing theoretical and technical matters); business (dealing with practical issues of the construction business and trade); social/public (taking the concerns and interests of the wider public and society with regard to topics ranging from architectural aesthetics, building codes and environmental implication of certain construction materials or practices) Advisory directing your particular questions or problems to the experts and getting a direct response. Events related to the industry. Tenders Price watch of basic building materials updated every 2 weeks. Market the classified-buying and selling, exchanging bartering, leasing, renting and so on. Directory of key sectorial operators and services. Construction Ahead, mar-apr 2006
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VERSATILITY, MANOEUVRABILITY, EFFICIENCY Have you ever imagined that all building site operations could be handled by one machine only? Manitou does it all. Earthmoving, lifting, concrete pouring, stack positioning, all can be done with this versatile, robust and very reliable Manitou machine. Whether for new constructions, or renovation, Manitou saves you time, cuts labour costs and increases productivity.
MGK PVT.LTD.CO
makonnen ethiopia plc IMPORTERS - EXPORTERS - COMMERCIAL AGENTS
Tel 551 45 36, 515 43 14, Fax 00251 11 551 44 76 P.O.Box 746 Addis Ababa, Ethiopia - mgk@ethionet.et
www.mgk.bz