Cầu Khỉ Monkey Bridges
ADVANCED ENGINEERING 1A AUTHORS Wenray Wang - Technical Guru Isobel James - Team Leader Matheesha Gunaratne - Drafter/All-rounder Amara Kruaval - Editor/Researcher Lasath Siriwardena - Design Director
Š 2012
ACKNOWLEDGMENTS A big thanks to our tutors Ron Johnston and Catherine Goonan for guiding us through this semester. Your support, sound advice and encouragement really helped shape our final design. We’d also like to thank University of Sydney and Engineering Without Borders for providing the fantastic Advanced Engineering course.
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EXECUTIVE SUMMARY
The current safety of bamboo footbridges in the An Minh District of Vietnam is substandard. The following project aims to address the issue with descriptions and evaluations of design solutions generated. These ‘monkey’ bridges cross the numerous waterways that weave their way through the district and are used on a daily basis by most members of the community. The current construction generally consists of a singular 100mm diameter bamboo pole laid horizontally across a X frame, often with a bamboo handrail. This design leads to many bridge related injuries and fatalities every year, often due to people slipping and falling into strong currents. The risks are magnified in the monsoonal season each year, and often these bridges become simply unusable. The Vietnamese government has taken measures to deal with this problem by establishing programs to replace all the major monkey bridges with concrete alternatives. However these projects are expensive and take a long time to implement. They also do not accommodate for the smaller monkey bridges that are frequently used by smaller villages and communities. WIMAL’s project aim is therefore to improve these bridges with a low cost, culturally sensitive, environmentally sustainable and safe solution. Numerous approaches were considered, including demolishing the existing bridges and building new ones. Designs included a retractable bridge, a floating swivel bridge and a floating pulley bridge. These were eliminated because of their high cost, cultural insensitivity and impracticality which did not meet WIMAL’s objectives. Most impor tantly however, it was decided that these solutions did not maintain the aesthetic and traditional quality
of the original monkey bridges, which would undermine the ethical benefits of the design. With the key objective of improving the safety of the current bridges in mind, it was decided that traversing a wider, flat stepping area would be easier than walking across a cylindrical beam. WIMAL considered the best approach to installing an extra beam to widen the walking area, however, the surface would still not be flat and thus relatively difficult to walk across. The final design had the basic principle of having a platform placed on two bamboo beams to provide the flat surface. The most significant problems arose when assessing the stability of such a structure and when deciding on the connection between the platform and the bamboo beams. Numerous design proposals were put forward using bolts, screws and adhesives. However, it was finally decided to use existing cultural techniques and lash the elements together. The platform would be broken up into sections like stepping stones, allowing it to be highly adaptable to any existing bridge design. As well as using existing building techniques, local materials were also utilized in this design. Bamboo and acacia wood were chosen for the platform attachments. These materials are locally grown and commonly used by the Vietnamese people. The final design could potentially be implemented in An Minh and surrounding Vietnam today. The solution is commercially viable, self-sustainable and can provide countless benefits to the current Vietnamese population. - WIMAL 23 October 2012
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TABLE OF CONTENTS 1 Introduction 1.1 Design Area: Transportation
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1.2 The Problem
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1.3 Primary Objective
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1.4 Objectives and Considerations
2 BackGround
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2.1 Geography
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2.2 Geology
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2.3 Climate
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2.4 Environment
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2.5 Culture
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2.6 Demographics
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2.7 Transportation
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2.8 Current Monkey Bridges
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3 Design Concepts
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3.1 Platform Additions
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3.2 Floating Swivel and Centre Anchor
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3.3 Pulley System
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3.4 Floating Swivel Along Edge Using Tide
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3.5 Retractable
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3.6 Comparison of Designs
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3.7 Selection Criteria
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4 Final Design
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4.1 Overview of Design
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4.2 Platform Materials
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4.3 Structure Material
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4.4 Joining Platform to Monkey Bridge
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4.5 Solutions
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4.6 Construction Drawings
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4.7 Prototype Construction
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5 Implementation 5.1 Pilot Project 6
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5.2 Implementation Options
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5.3 Workshop Implementation Method
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5.4 Instruction Implementation Method
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5.5 Implementation Comparisons
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5.6 Project Costing
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5.7 Project Costing Workshop
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5.8 Implementation sustainability
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6 Practical Consideration
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6.1 Social
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6.2 Environmental
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6.3 Economic
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6.4 Maintenance
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6.5 Future Improvements
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6.6 Feasibility
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6.7 Strength
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7 Ethics
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7.1 Demonstrating Integrity
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7.2 Practice Competently
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7.3 Exercise Leadership
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7.4 Promote Sustainability
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8 Conclusion
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9 Reflections
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10 References
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Appendix A: Risk Assessments
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Appendix B: Conceptual Sketches
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Appendix C: Add-On Concept Comparisons
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Appendix D: More detailed research
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Appendix E: Project Proposal
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Appendix F: Calculations
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Appendix G: Construction Manual
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1 Introduction
1.1 Design Area: Transportation ‘Transportation is an important issue in the Mekong Delta region. Residents use a wide range of transportation methods, including bikes, motorbikes, buses, and boats. Due to the large number of canals, boats are particularly valuable. The current transport system also suffers from inefficiency and congestion; consider ways to improve the system as a whole.’ (EWB, 2012) It was decided to approach the problem of transportation by targeting the crucial transit networks of the Mekong Delta region - bridges. People of all demographics use this transport system and is more common in our target area of isolated rural villages where transportation by boat is simply impractical or too expensive.
1.2 The Problem Over 41000 kilometres of natural waterways flow across the landscape, and 8000 kilometres of these are used regularly for commercial purposes (World Bank 2007). It is understandable that these canals and rivers play a central role to the daily lives of those in Vietnam. Boats and barges are the most common methods of navigating the waters and there has been rapid growth in the sector in the past decade. However, many rural communities or families may simply be unable to afford a boat, and rivers or canals may only be traversed by foot. This is where the rural footbridges or ‘monkey’ bridges fulfil their purpose. These monkey bridges generally consist of a single 10cm diameter bamboo pole supported by a simple X-frame on either side of the bank. Families in Kien Giang province must traverse these bridges on a daily basis. In the wet season of the year, children are unable to cross these bridges entirely, and education suffers as a result. The bridges also create a barrier to farmers who must find other, more costly methods of transporting goods across waters. While there have been efforts by the government focused on the replacement of unsafe bridges, funding is unstable and the government initiatives are unable to cater for the smaller rural communities of Vietnam.
1.3 Primary Objective Our primary objective is to design safer ‘monkey’ bridges for the An Minh District in Vietnam. The bridge should be low cost, culturally sensitive and long-lasting. WIMAL proposes an appropriate design of the current monkey bridges to provide a sustainable and financially viable solution to improve the safety of transportation by foot. Even though the EWB challenge is set primarily in the An Minh District of Kien Giang, we hope that our design could be implemented elsewhere in Vietnam and potentially other delta regions in neighbouring countries. Part of improving the safety of bamboo bridges in Kien Giang is to uphold basic human rights. The Universal Declaration of Human Rights along with the basic needs of food, clean water and shelter, the access to safe and easy transport is also a basic human essential. When the consequences of 9
unsafe bridges are considered – children unable to be educated or injured villagers unable to reach nearby hospitals – the magnitude of the issue becomes much clearer. The success of a bridge in Vietnam depends on the ability for it to be realistically implemented into daily life. This covers the manufacture, installation, use and maintenance of the bridges. This seamless integration can only be achieved if the following objectives are upheld.
1.4 Objectives and Considerations WIMAL has identified the following objectives as a guide to design development.
Cultural WIMAL has considered the possibility that the proposal of an alternative bridge design replacing traditional bridges will be met with conflicting responses. Monkey bridges have been a part of the Vietnamese culture for thousands of years and thus they hold a deep significance to the people of the region. Methods of construction, local material use and skills have been passed down and improved on through generations. This is why WIMAL sees the preservation of not only the aesthetic of the current bridges as important, but also the method of construction, skills and styles of the current bridge design. The Government is in the process of implementing large concrete bridges to replace the monkey bridges along the busiest transport routes; however these bridges take time to implement especially in rural areas. Funding is unstable and due to the remoteness of some monkey bridges the smaller bridges that are used by children and the elderly multiple times a day are unable to be replaced.
Functionality We have recognized cultural sensitivity as an important objective of the project, however the functionality and implementation of the bridges needs to be realistic. Our design will cater to the existing local skills in order for the implementation and maintenance of the bridges to be successful. For example, the method of joining in rural Vietnam consists of lashing using bamboo rather than bolting, thus our design needs to take aspects like this into consideration. Due to the variable nature of Monkey Bridge design, any solution must be adaptable to suit a wide range of bridges and conditions. The monsoonal conditions in Vietnam can cause the rivers to flood and the currents to increase, thus it is imperative that the bridge is able to withstand such forces as well as everyday fatigue as people cross it. To achieve design longevity we must reduce the number of moving parts in the bridge.
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Safety Increasing the safety of the people crossing over the canals is our primary objective. Our design must make the bridges significantly safer to walk across and also broaden the demographic that crosses the rivers, namely children and the elderly. By reducing the dependence on the handrail another potential problem in transporting heavy and bulky goods across the thin bridge can be solved. Solving this problem will increase productivity and lower the cost of transportation of goods.
Environmental Any changes in bridge design must preserve or create minimal impact on the existing conditions along and adjacent to the bridges. This land is often soft soiled and prone to erosion, it may also lie on peoples land and therefore any actives such as heavy excavation will not be acceptable. In order to reduce the transportation costs the materials must be locally sourced (reducing the need for transportation) and sustainable. Materials such as bamboo, melaleuca wood and acacia magnum should be used effectively due to their high sustainability.
Cost Though all of the above objectives must be fulfilled for the project to be successful, the cost of the project will always be one of the key areas when deciding whether the project will go ahead. To be viable in the An Minh district, this project must be cost effective, easy and quick to implement.
Environmental
Must be able to withstand harsh climatic conditions Use sustainable materials
Safety
Minimise carbon footprint
Cost
Minimise the number of moving parts Simple design Minimise maintenance and installation costs
Local labour and construction
Cultural
Cater to aging community Reduce monkey bridge related fatalities and injuries Increase lifespan of existing bridges
Respect local customs and beliefs Assimilate with current aesthetic
Functionality
Ensure there is no conflict with existing initiatives
Cater to aging community Ensure the design can realistically be implemented Create an adaptable design to suit a range of conditions
Bamboo Bridge Objectives Figure 1.1 Mindmap of the bamboo bridge design process
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2 BackGround
2.1 Geography Kien Giang is situated on the south western tip of Vietnam on the Mekong River Delta with a 207km coastline boarding the Gulf of Thailand. It has 15 districts with a total area of 5638km2 (Quoi, 2010). An Minh is a coastal district, located in the south of Kien Giang Province.
2.2 Geology The physical features of the Mekong Delta is comprised of mountains, highlands, plateaus, valleys and broad, low lying, flat flood plains. Since Kien Giang is in the low-lying terrain of the delta region, its topography is extremely flat, ranging from 0.8m to 1.5m above sea level (Brown et al 2010). This province is especially vulnerable submergence and subsidence of land from the predicted rises in global sea levels. More specifically, An Minh exhibits plain terrain, formed by alluvial sedimentation many years ago. This process involves the deposition of eroded silt and sediments as water flows slows down in the lower Mekong Delta (Encyclopaedia Britannica 2012). The Holocene Alluvium, which blankets virtually the entire Mekong Delta region, consists of unconsolidated silt and clay with some layers of sand (Nguyen et al 2005).
Figure 2.1 Location of An Minh District within Kien Giang Province
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Figure 2.2 Location of Kien Giang Province
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Soils in An Minh fall into the category of salic fluvisols. These soils are characterised by clear strata layers, and ideal for growing rice crops and aquaculture (Encyclopaedia Britannica 2012). The soils present in the province form up to 70 centimetres in thickness and are extremely fertile and well suited to farming. The traditional houses are built above ground and monkey bridges work very well in these conditions because of their columnar foundations.
2.3 Climate Climate in the lower latitudes of the Mekong Delta, such as the Kien Giang province, is classified as an ocean tropical climate with a wet season that lasts the majority of the year. The seasons are separated into the rainy season which lasts from April to November and the dry season from December to April (Nguyen et al 2008). Though An Minh district in the Kien Giang Province is not susceptible to typhoons, the area is prone to flooding from monsoon rains as it lies on a very flat, low-lying coastal terrain of the Mekong Delta. The rivers and canals that stem from the Mekong River flood the surrounding fields each year to a level of one to two metres (Nguyen et al 2008). The monkey bridges are constructed so that the bamboo beams are higher than the flood water levels in the canals to allow land transportation, however, especially during the wet season, the beams are extremely slippery and the currents are swift, leading to fatalities when locals lose their footing. In the drier months, when canals and rivers are not saturated with rain water, they are affected by salt water intrusion and increasing sea levels as a result of climate change (Brown et al 2010). The threat of rising sea levels on the low lying land means that bridges are becoming more important to everyday life in Kien Giang. It has been predicted that even with the most conservative estimates, the sea level will rise 15 centimetres by 2030, threatening lives and forcing residents to relocate (Mackay et al 2011). The increased water level and more frequent flooding would reduce the gross domestic agriculture product by 20% and reduce industry and services by 10% across Vietnam (Mackay et al 2011). Kien Giang will suffer more severely due to its comparably lower elevation.
2.4 Environment With the terrain and climate ideal for water-rice agriculture, Kien Giang has vast and fertile flood plains for rice paddies and agricultural fields, with small communes situated along the network of canals. These characteristics are also evident in other provinces that are situated on the Mekong Delta. Rice growing is the predominant agriculture in Ah Minh district, but as a coastal district of the Kien
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Giang province, the Ah Minh district is also an established fishing ground. Within Kien Giang, over 70,000 hectares of land is dedicated to aquaculture (Vietnam Business Forum 2012). While the majority of fishing is carried out offshore, with a fleet of 7500 fishing vessels, fisheries in villages are also common. The monkey bridges are highly elevated to allow boats to pass under unobtrusively. Villages close to the coastline commonly fish adjacent to the coastlines along the sea grass beds. Commonly fished in Kien Giang are mackerel, anchovies and trevally (Kampot Fisheries Cantonment 2009). The vegetation in Kien Giang consists primarily of forests, namely melaleuca trees, and mangroves (Quoi 2010). The salt tolerant plants which naturally grow in sandy mud increase soil strength due to their extensive root systems (Doran 1999) and provide good foundations for the installation of the X-supports of the monkey bridges. The mangroves that line the coastline are also invaluable to farming as they shield land against rising sea levels and storms (Brown et al 2010)
2.5   Culture Life in the Mekong delta is centred around the river, with small villages and communes easily accessible by rivers and canals. There is very little emphasis on road development in these areas and the major mode of transport includes commuting by foot, bike or boat. The main method of transportation of goods in Vietnam is by road, across bridges or by water. People often carry baskets, stretchers or sticks to transport merchandise on bicycles or carts. Various boats and canoes are used to transfer goods by water. The agriculture is characterised by rice growing, with skills passed down through the generations. Raising animals such as pigs or poultry and fishing is also common within families (Vietnam-Culture. com 2006). Recently, more focus has been placed on developing tourism in Kien Giang province. Some $411 million US dollars are planned to be invested into improving cultural and ecological tourism infrastructure and it is predicted that in 2020 the province will attract 650,000 international visitors. (Government Web Portal 2012) Kien Giang is currently undergoing social-economic transformation. Education rates are high in urban centres, with the rate of children attending primary school to reach 97% in the year 2012 (Vietrade 2012). However, in rural areas, the education rate is much lower, and there are high rates of illiteracy (Sahaya International 2012). The people in Kien Giang are separated into several ethnic groups, namely the Kinh, Khmer and the Hoa people (Sawadee 2002). The Kinh ethnic group originated from Northern Vietnam and China and make up the majority of Vietnam’s present day population.
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Content
Create an adaptable design to suit a range of conditions
Environmental
Must be able to withstand harsh climatic conditions Modulus of Rupture 106N/mm 2 Use sustainable materials Modulus of Rupture 106N/mm Minimise carbon footprint
Safety
2
Rate
adial Shrinkage
0-1000kg/m3 N/mm2
Bamboo Bridge
Cater to aging community Reduce monkey bridge related fatalities and injuries 3% Tangential Shrinkage Increase lifespan of existing Must be able to withstand bridges harsh climatic conditions
Cost1.2% Radial Shrinkage
Environmental
Minimise the number of moving parts The majority of the60N/mm Kinh people live in small villages made 2 Grain Compression Simple design up of severalMinimise families. These small villages often combine maintenance and installation costs to form larger district villages. The village people elect their
Cultural
Use sustainable materials Respect local customs and beliefs Minimise carbon footprint Assimilate with current aesthetic 1.5m Minimise Ensure there is no conflict with the number of to moving parts existing initiatives Simple design 0.8m Above Sea Level Minimise maintenance and installation costs
Cost
labour3% andTangential Shrinkage ‘Council Local of Notables’ who administer and construction
own govern their Functionality own affairs and workforces. These village customs are so community significant that they take precedenceCater overto aging the King’s laws Ensure the design can (Nguyen, 2005). Excessive should be realistically be implemented 12% foreign Moistureinvolvement Content Create an adaptable design avoided as it may cause adverse reactions and hinder the to suit a range of conditions cooperation. 40kN/cm2 5kN/cm2 37kN/cm2
F
Local labour and construction
F
Functionali
Modulus of Rupture 106N/mm2
Bamboo Bridge
Buddhism is the leading religion in Vietnam. The key 2% Moisture Content spiritual ideas of the religion 2are the path towards being 9.25N/mm Shear Rate 26% Predicted Elderly free from suffering and hardship by overcoming craving. Poplation in 2050 60N/mm2 Grain Compression Average Monthly Wage To live a life of virtue one must live by the ‘Noble Eightfold 2 Tensile Strength ompression Modulus of Rupture 106N/mm Path’ F which defines the right ways of living and conducting AUD oneself. Rituals are regularly held in temples which are 1.5m N/mm2 Shear Ratelocated in each village and families often worship Buddha to at home (Te 2012). 60N/mm2 0.8m Grain Compression
Cater to aging com Ensure the design realistically be imp Create an adaptab to suit a range of c
$182 Bamboo Bridge
2.6 Demographics
Above Sea Level
Rural Monthly Wage 40kN/cm2
$69
5kN/cm2
0.8m Above Se
37kN/cm2
Vietnam is currently a population Densityexperiencing 560-1000kg/ma3 decreasing rate of growth (Roy, Amlan 2010) as a result of the declining rate of fertility and mortality, and an increase in the population’s median12% age and life expectancy. of labour workforce 26% Predicted Elderly 2 40kN/cm 5kN/cm2 37kN/cm2 educated 1m 3 Poplation in 2050 Density 560-1000kg/m The aging population is increasing at an accelerated pace Tensile Strength with predictions of the elderly population spiking to 26% in 2050 from 7.5% in 2005 (Vietnam Trade Promotion Agency 26% Predicted Elderly 2011). This is especially true in more rural areas, such as Poplation in 2050 An Minh in the Kien Giang Province. The monkey bridges Tensile Strength are especially unsafe for the elderly struggling to cross the many canals that criss-cross Ah Minh. 88% of labour
kN/cm2
r workforce
The monthly wage of an average Vietnamese Citizen is $185 USD, or 3.84 million VND (Thanh Nien 2012). However, while the GDP in Vietnam is constantly increasing at a rate of approximately 10%, there is a large inequality between urban and rural incomes (Akita et al 2008). Current rural income is just above $70USD, with 16.2% of Vietnamese population considered to be poor (VNA 2009).
1.5m to
AUD
26% P Poplat Tensile Strength
workforce uneducated
12% of labour workforce educated
12% of labour workforce educated 17
Education in rural areas also remains low, and 50% of villages do not have schools, and 88% of the labour workforce remains uneducated (Akita et al 2008).
2.7 Transportation Ah Minh District is centred around the system of canals that have formed in the flood plains throughout the Mekong Delta. The canals are the main routes for transportation and form the same purpose as roads, with boats being the main mode of transport for both people and trading goods. Though they are extremely valuable, the cost of diesel fuel makes it unaffordable for the majority of residents. On land, there are also narrow roads for motorbikes and bicycles that run along the canals and in between the rice paddies. Narrow bridges and ferries carry people and bikes from one side of the canals to the other. The Kien Giang government has identified, in the special issue of Kien Giang Union of Friendship Organisations (2011-2016), transportation is an important issue in the Mekong Delta region. Initiatives developed to improve transportation include the construction of transportation routes in rural areas and concrete bridges to replace the footbridges. While the government has prioritised the construction of concrete bridges to replace monkey bridges, this is not viable in more rural areas where smaller bridges are used for people crossing only. The monkey bridges further away from the main communities are made from local materials and must be regularly maintained by the residents.
2.8 Current Monkey Bridges Current monkey bridges are extremely unsafe, and claim the lives of many children and adults alike every year. The crossings become especially dangerous in the wet season, where slippery footings and fast flowing waters often make the bridges unusable.
Deaths In 2009, seven teachers and grade 3 students in Kien Giang drowned after slipping into the river. The local elementary school has repeatedly petitioned to have the bridge improved but the council has not acted as of yet. Currently, over 3000 people are affected by monkey bridge incidents a year in Ca Mau province which is adjacent to Kien Giang (Orange Partners 2012). However, most incidents in rural Vietnam go unreported due to the isolated nature of rural villages. (Department of Biostatics 2004). Many more deaths in Vietnam are also due to the inability to safely transport patients from
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the remote villages across rivers and canals. This also contributes significantly to the low use of public health 22.4% Rural Villagers services of 22.4% (Department of Biostatics 2004). Children often carry bicycles across the monkey bridges, and the elderly villagers Low do not cross. It is a common Usedare of Public sight to see ‘old Health men standing side of the bridges, Serviceseither due to bridges waving hello to each other, but not dare cross the bridge’ (TechInfo Vietnam 2009).
Societal Impact More important is the effect of the unsafe bridges on industries and retailers. Agricultural products are often not able to be transported inexpensively across rivers, which new government leads to goods being sold at drastically reduced prices. The reverse is also true – small businesses bridges were are afraid to buy large quantities ofcompleted goods because the high transportation in of2003 costs and the lack of consumers and profit. (Tinmoi 2012) Education is also greatly affected during the wet season when children are unable or unwilling to cross the bridges to attend class.
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Teachers and Students
22.4% Ru
Low Use of Public Health Services due to bridges
2009, 7 Monkey bridge related deaths
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new government bridges were completed in 2003
$2000AUD
Government Initiatives
$2000 AUD initiatives have been created to remove and Government
$700AUD replace unsafe monkey bridges. However, progress has been extremely slow. In 2003, 8 billion Vietnamese dollars (approximately 400,000AUD) were invested in the removal of the bridges in 14 provinces of the Mekong Delta region. However, since the construction time required to implement “The goal is to remove all the new bridges meant that only 237 new bridges were AUD the monkey bridges...and completed in 2003. Despite the government cutting costs improve by employing the help of young men to complete the the roads and motorways” bridges, funds are running low and progress has slowed (VietBao 2004).
$700
The new concrete bridges built by the government are extremely expensive, with larger bridges costing 35-50 million (1700-2500 AUD) and small bridges 10-20 million Vietnamese dollars (500-1000 AUD) (Figure 2.4). The construction time for these bridges average 1 to 2 months.
“The the m imp
Construction Time
30-60 days
“The goal is to remove all the monkey bridges...and improve the roads and motorways”
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Presently, the Go Quao district in Kien Giang no longer has any monkey bridges (VietBao 2012). Some residents have also taken matters into their own hands by raising money to fund the removal of bridges in their area. Over the course of 20 years, Six Nguyen of the Ben Tre province of Vietnam has remedied the inconvenience of rural crossings by overseeing the labour hire, supplies and construction of 50 concrete bridges (VOV 2012). She has since won the third-class Labour Medal in Vietnam for her services. Recently, approval has been given by the Prime Minister of Vietnam to “develop transportation planning [in] key economic regions of the Mekong Delta [from] 2020 to 2030� (Saigon Giai Phong Online 2012). The goal is to remove all monkey bridges over the next few decades and improve the roads and motorways in the country.
Current Bridge Replacement Design The replacement concrete bridges are costly and have a long construction period. On average, the raw materials of a 20m long footbridge costs $2900 AUD or 67,000,000 VND (TechInfo Vietnam 2009). While this may not seem expensive for developed countries, these bridges are simply unaffordable for the vast number of rural communities in Vietnam.
Figure 2.3: Existing Monkey Bridges in Vietnam
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Government Concrete Replacement Bridge
Figure 2.4: Elevation, plans and sections of a current concrete monkey bridge design
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Over 3000 monkey-bridge related incidents near Kien Giang are reported annually.* Most incidents go unreported due to the sheer remoteness of villages.
*Source: Orange Partners 2012
3 Design Concepts
Keeping the objectives listed in the introduction in mind (1.4 Objectives and Considerations), WIMAL generated a number of possible designs to meet the transportation needs of the Ah Minh community.
3.1 Platform Additions Design concept 1 modifies the existing monkey bridges to increase safety and ease of use while maintaining the aesthetic properties of the monkey bridges. Platforms are attached to the large bamboo pole used to walk across. These platforms act as stepping stones to ensure sure footing when crossing the monkey bridges as the original bamboo pole is very narrow, and has low traction when wet. The platforms will be 25 x 30 cm and are spaced approximately 15-20 cm from each other. These ‘stepping stones’ are attachable to any bridge regardless of length and adaptable to the varied factors and designs of monkey bridges. It is an interim solution for the monkey bridges that are to be replaced with concrete bridges through the government initiatives. However, this is a more sustainable and viable option in instances where the smaller monkey bridges are used by fewer locals that cross over smaller lengths.
Figure 3.1: Concept sketches of the platform addition design.
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3.2 Floating Swivel and Centre Anchor Design concept 2 is an alternative design to replace monkey bridges which addresses the constantly changing water levels in the canals and rivers. The design consists of a central raft floating in the middle of the canal which enables the bridge to swivel parallel to the canal when boats are passing and perpendicular to the banks for land transportation (Figure 3.2). The raft is anchored to the bottom of the canal so that the axis of rotation remains stationary against the currents. This design reduces fluid resistance on the raft by retaining the shape of traditional Vietnamese canoes, aesthetically complementing their culture. The proposed method of flotation uses the buoyancy effect of capped recycled water bottles. This assists waste management and encourages recycling.
Figure 3.2: The operation of the centre anchored bridge concept.
3.3 Pulley System Design concept 3 is a pulley transportation system of enclosed floating platforms that allows the user to pull themselves across the canal safely and more efficiently, especially when traveling with goods. The system has two support poles, each with pulleys on top, which are both cemented into the canal banks. To travel across the canal, the user enters a raft-like segment with a loose rope inside. The user will then pull the rope, causing the raft to move. This method employs pulleys to reduce the force needed to pull the segments from one side of the canal to the other.
Pulley System 26
Floating Swivel and Centre Anchor
3.4 Floating Swivel Along Edge Using Tide WIMAL’s fourth design concept, similar to the second design, floats on the river but pivots along the edge. The bridge floats on the water, using the same method of recycled water bottles for flotation, but only swivels in one direction. The mechanism of this alternative relies on the water current. The raft is kept parallel on the canal bank to allow boats to pass. To use it as a bridge, the raft must be pulled upstream and anchored at a fix point. When the unanchored end is pushed towards the other bank, the hinging movement of the raft is assisted by the flow of water. The raft will stop perpendicular to the bank by a docking mechanism on the other side (Figure 3.3). The raft is released by releasing the docking mechanism. The water current takes the raft back to the initial position to be used by the next local traveling in the same direction.
Figure 3.3: The operation steps of the edge-swivelling design.
3.5 Retractable Design concept 5 is a retractable bridge of identical components on each side of the canal. The rationale behind using a retractable system is to allow boats to travel through the canal without having to worry about hitting the bridge. If the canal or river is narrow enough, a one-sided retractable design is adequate. The bridge is retracted to be stored vertically, and when required, it is released to flatten itself out to produce a bridge. The mechanism is composed of three pivots connected to bridge members. When the rope connected to the furthest member from the canal bank is pulled, the bridge retracts.
Retractable System 27
3.6   Comparison of Designs The advantages and disadvantages of each design are comparative to the existing monkey bridges in the area. Table 1: Comparison between each concept design
Design One:
Platform Additions Advantages Disadvantages Cultural Maintains the aesthetic of the culturally significant monkey bridges thus not negatively affecting tourism as the monkey bridges are an icon of the area
Cost The initial and repairing costs of the bridge is High chance of destruction during monsoonal minimal weather increases long term costs Significantly less labour intensive than other options Functionality Easy to maintain It does not improve any structural problems that the bridges may have and thus in monsoonal Uses current infrastructure weather it may be destroyed Due to it’s ability to be quickly constructed onIt is not a permanent solution to the problem site, there is no need to shut down the bridges for long periods of time Safety Reduces the chance of slipping and falling into Integrity of original monkey bridge is assumed. the water by providing a flat, rough surface. Environmental Uses local processes that are adapted to the locals technical skills Uses locally sourced and sustainable materials
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Design Two
Floating Swivel and Anchor at the Centre Advantages Cultural
Disadvantages Lacks the aesthetic of the original monkey bridge, possibly affecting the use of the bridge and the tourism brought in by the monkey bridges
Cost Due to its ability to be removed its longevity is More expensive to construct due to the increased, reducing long term costs compared increased amount of materials used to existing monkey bridges which are potentially Increased labour cost compared to existing damaged bridge due to the more complex design Functionality Allow for bicycles and larger objects to cross Space for boats to pass through the canal over the canals with the bridge’s raft in the centre may not be enough in some of the narrower canals The raft design allows for the bridge to be transported to various locations when needed Able to be moved onto land during monsoon season, increasing the longevity of the bridge.
Safety Increased surface area compared to existing Possibility that when a load is applied at one monkey bridges for walking which greatly end of the bridge it may tilt, making it unstable reduces the chances of falling into the water and unsafe to use May wobble when there is an increased current, making the bridge more difficult to cross
Environmental Use of recycled water bottles helps clean the Anchor may disrupt river flow, causing currents heavy polluted Mekong River to slow, affecting the quality of the river. Uses mainly locally sourced and sustainable materials
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Design Three
Pulley System Bridge Advantages Cultural
Disadvantages Design lacks the aesthetic of the original monkey bridge.
Cost Mainly local materials so the money stays within the community
Use of pulleys and rope increase the expense of the design More Bamboo used in this design compared existing bridge, increasing cost
Functionality Allows for the transport of multiple people or Pulley system has a lot of potential to fail due to cargo the high number of moving parts Clears ground head space for boats to travel Force required for the bridge to be pulled is through potentially too high for the aging population
Safety Increased surface area compared to existing Pulley may become stuck or tangled, which monkey bridges for walking which greatly may lead to a user becoming stuck on the river. reduces the changes of falling into the water Operates on the river surface so that injuries relating from falling from a height are reduced. Environmental Uses mostly locally sourced and sustainable materials
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Design Four
Floating Swivel with Anchor at the Edge Advantages
Disadvantages
This design has the same benefits as Option 2 Cultural Design lacks the essence of the original monkey bridge
Cost Due to its ability to be removed its longevity is Another bridge is required fur ther down increased, reducing long term costs compared the canal to ensure access from both banks, to existing monkey bridges which are potentially increasing cost damaged during monsoon season Increased labour cost compared to existing bridge due to the more complex design Functionality Simpler construction process than Option 1 Swivel system only works one way so operation can only occur from one side Due to simple design, easily adaptable to The force required for the bridge to be pulled various canals upstream could be too much for the aging population If the current of the water is not enough the swivelling mechanism will not work.
Safety More structurally stable than Option 1
Possibility that when a load is applied at one end of the bridge it may tilt,
Increased surface area compared to existing monkey bridges for walking which greatly May become unstable in fast currents reduces the changes of falling into the water
Environmental Has greater resistance to monsoonal weather conditions than existing bridges due to a lower contact area for winds Uses mostly locally sourced and sustainable materials
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Design Five
Retractable Bridge Advantages Disadvantages Cultural Once retracted, the bridge can Design lacks the essence of the original monkey bridge. disappear into the surroundings, becoming less visually polluting Cost None For the pivots, steel is required ensure structural integrity increasing expense and introducing outsourced materials, going against our goals of producing a product built for the community by its members. Supports for the bridge needs to be secured using concrete, as the banks are mostly unconsolidated soils, adding to the cost of producing the bridge If winch system is implemented, this would create additional cost and more outsourced production. Functionality Allows for larger boats to travel Overall design consists of too many moving components through the small canals creating an increased number of locations for failure For the mechanics to work; there must be a person on either end of the canal. This problem could be remedied through a hand winch system that links the two components of the bridge, allowing for the bridge to be retracted from either side. The amount of force required to operate the bridge would be too much for the aging population of the An Minh region. Safety Increased surface area compared to existing monkey bridges for walking which greatly reduces the changes of falling into the water Environmental Uses mostly locally sourced and sus- The use of steel is not sustainable and environmentally tainable materials damaging compared to bamboo or other local materials.
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3.7   Selection Criteria In the selection of the final design, we decided to comparatively rank (1-5) each design for each of our objective constraints constraint. We then decided to summate the ranks to produce a total figure. The one with the highest figure was the design we choice to pursue.
Considerations
Cultural Cost Functionality Safety Environmental Total
Existing Bridge 10 9 4 2 9 32
Anchor Centre Swivel 4 2 6 7 3 22
Anchor on Edge Swivel 5 4 8 8 4 29
Pulley System 3 5 5 6 2 21
Retractable Platform Addition 3 1 6 8 3 21
9 8 8 7 8 40
Selection Criteria Existing Bridge
1000+900400 + 200 + 900 + =
Centre Swivel
400+200600 + 700 + 300 + =
Edge Swivel
500+400800 + 800 + 400 + =
Pulley System
300+500500 + 600 + 200 + =
Retractable
300+100600 + 800 + 300 + =
Platform Addition
450+400400 + 350 + 400 + =
4 Final Design
4.1 Overview of Design As seen in the selection criteria, the attachment design solution was the best option to further develop and implement. It was the most simple design as it is a modification of the existing monkey bridge yet increases the safety and ease of use. It minimises the change to culture by avoiding radical alterations in aesthetic qualities and historical significance of the monkey bridges. The design is also a cheap solution to the problem of monkey bridge safety. The attachment consists of a 300mm bamboo section lashed adjacent to the existing bamboo pole so the platform can rest horizontally on top. These platforms act as1.2% ‘stepping widening the Radialstones’, Shrinkage surface area for the pedestrians to walk on.
3%
The design is extremely flexible and can fit to a wide range of existing bridge sizes. The platforms may be arranged in a ‘stepping stone’ layout (Figure 4.6, 4.7), or even as a continuous platform depending on the needs and budget of a certain community.
F
The dimensions of the final design was chosen to be 250mm x 300mm. This size was selected as it allows two feet to be placed simultaneously on each bamboo platform,12% which improves balance Moisture Content when walking across the bridge, especially if carrying a large load.
4.2 Platform Materials
9.25N/mm2 Shear Rate
The platform material was chosen to be Acacia Mangium timber due to its superior properties F timber. More information about bamboo and and cost when compared to bamboo and melaleuca Melaleuca timber properties of the materials is provided in Appendix D – More detailed research.
Favourable properties of Acacia Mangium Medium weight hardwood Density 560-1000kg/m3
(Density of 560-1000kg/m3) (Sein 2011)
40kN/c
It is a relatively lightweight wood to ensure minimal additional stresses to the preexisting bridges.
1m
Bamboo
35
3% 3% Tangential Shrinkage Tangential Shrinkage
1.2% Radial Shrinkage 1.2% Radial Shrinkage
FF
Relatively high strength wood
(Modulus of rupture: 106 N/mm2, Shear rate: 9.25 N/mm2, compression parallel to grain: 60 N/ 12%12% Moisture Content Moisture Content mm2) (Sein 2011). Can be used in construction and withstand the weight of at least 100kg for a typical 300 x 2250 x Modulus of Rupture 106N/mm Modulus of Rupture 106N/mm2 40mm plank. 2 2 9.25N/mm Shear RateRate 9.25N/mm Shear 2 2 60N/mm Grain Compression 60N/mm Grain Compression
F F
Tensile Strength Tensile Strength
Fairly low to moderate shrinkage
3 Density 560-1000kg/m Density 560-1000kg/m3
1.2% radial and 3% tangential shrinkage from green wood, 12% moisture content (Sein 2011)
2 40kN/cm 40kN/cm2
1.2% Radial Shrinkage 2 5kN/cm 5kN/cm2
2 37kN/cm 37kN/cm2
1m 1m
This property is desirable to ensure lashing and joints do not become loose over time.
3% Tangential Shrinkage
Easy to work with all tools.
1.2% Radial Shrinkage
Nailing and screwing does not significantly impact the properties of the wood such as strength – important for the ease of installation and production.
1.2% Radial Shrinkage Bamboo Bamboo
Steel Steel 12% Moisture Content
F
Durable when exposed to weather as long as there is no contact with the ground As the units will be situated on the bridge, no 12% Moisture Content ground contact will occur and durability is not compromised.
Timber Timber
2 Content 12% Moisture 9.25N/mm Shear Rate
F
Modulus of Rupture 106N/mm2 9.25N/mm2 Shear Rate
9.25N/mm2 Shear Rate 36
F
60N/mm2 Grain Compres
3% Tangential Shrinkage
dial Shrinkage
10-16
4.3   Structure Material
The main structural material for the design was chosen to be bamboo. In comparison with commercial tree harvests, bamboo is a highly sustainable resource due to its abundance, fast growth rates and harvest frequency. The Ministry of Agriculture and Rural Development estimate 1.4 million hectares of land is devoted to bamboo cultivation due to bamboo’s regular use as a structural building material throughout Vietnam. The existing monkey bridges are constructed from bamboo, % Moisture Content maintaining the aesthetic qualities of the pre-existing bridges. It also ensures that traditional skills and techniques will be utilized, maintained and developed during the design construction.
F
Modulus of Rupture 106N/mm2
Favourable properties of Bamboo
/mm Shear Rate 2
Incredibly strong and elastic building material for its size and weight.
60N/mm2 Grain Compression
Minimal additional stresses are created for the pre-existing bridge. High tensile strength
It is able to resist high tensile forces as the inner outer skin is naturally composed of extremely elastic cellulose fibres embedded in a lignin matrix (Li, 2004), with a tensile strength of up to 40kN/cm2. In comparison very strong wood fibres can withstand a tension of 5 kN/cm 2, while the highest tension steel can withstand is 37 kN/cm2. (Rottke, 2002)
Tensile Strength Density 560-1000kg/m3 40kN/cm2
Bamboo
Timber
5kN/cm2
37kN/cm2
Steel
37
3% Tangential Shrinkage3% Tangential Shrinkage
Unfavourable properties of Bamboo Higher shrinkage rate than wood
10-16% Shrinkage
10-16% Shrinkage
Shrinks 10-16% in cross section. It needs to be well aged before use.
F
F
Incredibly high tool wear
ntent
Due to high silica content in the outer zone, creating the need for constant tool sharpening and replacement. 2 Modulus of Rupture 106N/mm Modulus of Rupture 106N/mm2 Relatively low compressive strength
Low Compressive Strength Low Compr
This is due to bamboo’s longitudinal fibre structure, hence designs2 must avoid creating compressive forces within the 60N/mm 60N/mm2 Grain Compression bamboo.Grain Compression
e
4.4 Joining Platform to Monkey Bridge
000kg/m3
kN/cm2
Using bamboo as a construction material is principally beneficial; it is a cheap fast growing material with excellent strength properties and is currently used throughout the Mekong Delta. However Tensile Strength Tensile Strength connecting bamboo culms successfully can present difficulties.
Difficulties 37kN/cm 40kN/cm
5kN/cm2
2
2
Profile
5kN/cm2
37kN/cm2
Bamboo has a round profile with a hard slippery surface. Joints are either hand carved to fit the curve of the bamboo or culms are secured on top of one another, creating a large and bulky joint. Fibre Direction Bamboo is a composite material consisting of strong longitudinal cellulose fibres, the longitudinal orientation of the fibres is responsible for bamboos high tensile strength yet low compressive strength as well as the splitting of the culm when penetrated by nails or bolts.
Timber NaturalSteel Timber Bamboo Variations
Steel
Bamboo is a natural product and varies in diameter, length and quality. This inhibits the use of prefabricated solutions as each piece is individual and the joints have to be tailored to each culm.
38
4.5   Solutions For a comprehensive list of the possible solutions and their evaluations, see Appendix C: Add-On Concept Comparisons
Option 1: Screw Connection The bridge unit is constructed and secured using a combination of metal screws and bamboo lashing.
Figure 4.1: The screw connection between the platform to the bamboo poles. Table 2: Advantages and disadvantages of bolt connections
Advantages Disadvantages Screws provide a secure fastening that prevents The metal screws are not commonly used the unit from slipping underneath the bridge materials and would require a new skill set to be learnt to implement the design. Does not require complicated lashing techniques The exposure of metal to the humid and wet environment will shorten the service life of the add-on. The metal screws would increase the expense of the unit. Higher difficulties in manufacturing due to the drilling required. The structure of bamboo causes it to behave very poorly when cracks or sudden changes in section occur, especially in areas with high stress concentration (Arce-Villalobos, 1993) such as the area around a screw hole
39
Option 2: Friction-tight Lashing Due to the difficulties of using bolts and screws, WIMAL investigated Friction-tight Lashings. This method reduces the possibility of bamboo cracking by removing the need to notch or drill holes. The bridge unit is secured using local bamboo lashing techniques. This meets the WIMAL’s objective of maintaining cultural values by encouraging the utilisation of a common traditional method currently used to construct monkey bridges.
Figure 4.2: Example of friction-tight lashing using local techniques. Table 3: Advantages and disadvantages of friction tight lashing
Advantages Disadvantages Common traditional method that is currently Possibility of bamboo culms shrinking further used to construct monkey bridges, and loosening the connection. Tight connections are created using soaked Laborious hand construction green bamboo strips that shrink while drying, Static calculations on individual joints not creating a stronger joint (Rottke, 2002) possible (Rottke, 2012) Bamboo ropes are more wear resistant than standard ropes and have a tensile strength of 720kp/cm3 (Rottke, 2002) Reduce the possibility of bamboo cracking as there are no notches or holes
40
4.6   Construction Drawings
Figure 4.3: Exploded axonometric of bamboo bridge add-on
1. Bamboo ropes to redirect load away from beam (prevents bending) 2. Hole drilled into platform for support rope to be threaded through 3. Horizontal grooves for grip 4. Grooves cut into platform to spread load onto beams 5. Acacia mangium wood platform 6. New Bamboo beam to be lashed to platform and existing bamboo beam 7. Existing bamboo beam transferring the load onto existing columns
41
Drawings of Existing Bridge This is an example of a standard Monkey bridge in the Ah Minh district. It consists of a bamboo X frame with a single handrail attached along the X-frame arms. The main bamboo beam is lashed onto the intersection of the X-frame. It connects to the banks of the river through two slanting poles which act as ramps (Figure 4.4, 4.5).
Existing Plan
Figure 4.4: Plan view of existing monkey bridge
Existing Elevation
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Figure 4.5: Elevation of existing monkey bridge
Drawings of Modified Bridge These drawings represent a generalised layout of how the platform additions will be implemented onto the existing bridges. The platforms can be situated as shown in a stepping stone like format with ropes attaching them to the existing handrail (Figure 4.6, 4.7).
Modified Plan
Figure 4.6: Plan view of monkey bridge with platform additions
Modified Elevation
Figure 4.7: Elevation of monkey bridge with platform additions
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Section of Platform Addition
1. Bamboo hand rail lashed to bamboo support column with rope attached. 2. Bamboo rope connecting hand rail and platform. 3. Bamboo support column 4. New bamboo beam to be lashed onto existing beam 5. Acacia Mangium wood plank to be lashed onto bamboo beams 6. Existing bamboo beam 7. Lashing connection of the bamboo columns 8. Bamboo support column
44
Detail Section of Platform Addition
45
Detail Plan of Platform Addition
1. Bamboo rope 2. Grooves for grip 3. Modified square lashing 4. Acacia mangium platform 5. Shear lashing 6. New bamboo beam 7. Existing bamboo pole 8. Drilled hole for lashings
46
4.7 Prototype Construction The prototype constructed was a 3 platform section of a monkey bridge. The production of the prototype was an essential component in developing the specifications of the final design. This was achieved by resolving the design and engineering flaws discovered during construction. WIMAL aimed to present the prototype of the final design alongside a same length section of the existing monkey bridge to allow for a more apparent comparison of the increased safety and ease of crossing the bridges. The two lengths of bamboo were placed parallel and on either side of the erected handrail. The handrail and the bamboo poles supporting the handrails was an improvised creation. It would usually be attached to one of the bamboo poles used X-support where the bamboo pole used for walking across the canal would rest and be lashed. Having the handrail structure and the bamboo beam section separate enables the prototype to be inspected in greater detail. This also permits a more thorough demonstration and explanation of the lashing as the prototype can be held and rotated along during the presentation.
Materials and Equipment Used • 85m Sisial Garden Lashing • 2x 2.4m long Bamboo Poles (80-100mm Diameter) [Bamboo beam] • 2x 1.5m long Bamboo Poles (80-100mm Diameter) [Handrail Support Columns] • 3x 0.3m long Bamboo Poles (80-100mm Diameter) [Platform Support] • 1x 2.4m long Bamboo Poles (50mm Diameter) [Handrail] • 4x Camping Tripod Seats • 3x Pine Platforms (18x240x300mm) • 12m Sisal Camping Rope [Platform Cable Support] • 6x Tent Pegs
47
Method Material Preparation (page 52-53) 1. Raw materials were cut to the specified sizes above (bamboo was bought at 2.4m long poles and the pine plank was18x240x1100mm) 2. Each handrail support component had triangle shaped pieces removed from the top with a base length of 5.5cm and a height of 9cm, producing a V shaped resting area for the handrail 3. Four holes were drilled onto the end of each 0.8m bamboo pieces to allow for tension cables 4. The handrail component was drilled with two holes at either end 5. The platform components have four holes drilled into them, their centres being 20mm from edges of the platform, using paper template to ensure efficiency and accuracy on each platform 5. Grooves routed on platforms for additional grip (using template again) 6. Each walking-on component had 2 holes drilled on either ends
Assembly (page 54-55) 1. The position of each platform was marked onto the bamboo beam 2. Platform supports were lashed to the walking-on component using shear lashing 3. Modified square lashing was used to attach the platform to the top of the bamboo beam and platform supports 4. The hand rail was lashed to the handrail support columns at each end 5. The handrail support columns were stabilised using guide wire and tent pegs 6. The bamboo beam with the platform attachments was lashed to the tripods to prevent rotation and slipping 7. The platforms’ cable support was tied onto platform and handrail
48
Prototype Construction Reflection Elevation of the bamboo beams It was initially planned to produce the top section of the X-support of the monkey bridge where the bamboo beam would sit. In order to have the platforms elevated at approximately 300mm above the ground (Figure 4.8). Replicating the traditional X-support by lashing two bamboo poles together was not a viable option so a flush connection was attempted by cutting the bamboo before lashing them together. This proved to be a costly and labour intensive appropriation because it was extremely difficult to produce the cut that would allow a secure flush connection with the bandsaw due to the irregular and inconsistent circular profile of the bamboo. A handsaw would have been more accurate but using the bandsaw was already extremely time consuming.
Figure 4.8: Initial X-support piece that proved to be unviable.
Instead, camping tripod seats were employed to elevate the bamboo at a consistent height above the ground, which was the most effective and efficient solution to elevating the bamboo beams.
Stability of the Handrails Since cable supports for the platforms are attached to the handrail to maintain horizontality of the platforms, the stability of the handrails was extremely important. To appropriate the current monkey bridge to the prototype so it was feasible to build with the equipment and materials available, and for safety reasons, bamboo poles were used as support columns for the handrail.
Figure 4.9: Handrail support
The handrail sits in V-shaped cuts at the top end of the bamboo columns on each side, which would normally be lashed on to the longer arm of the X-support. Holes were drilled into the supporting bamboo column and the handrail to safely connect them to one another more tightly when lashed together (Figure 4.9). This ensures the handrail cannot roll (Note that the lashing used to keep the handrail on the support columns does not mimic the traditional Vietnamese lashings for the monkey bridges). 49
Strength of the Lashing Material As bamboo rope and lashings are not readily available to be used in the prototype construction, twine was used because it had the most similar properties. The assembly of the prototype took longer than expected due to the inadequate strength of the lashing material. The first type of twine used during the production of the prototype broke with any tightening action and could not retain any of the necessary tension and surface area to hold the weight of a person on the platform (Figure 4.10). It was then evident that a thicker twine was a stronger lashing material. It is important to note that this problem will not occur in the actual implementation in An Minh due to the installers having access to the recommended and widely available traditional materials of bamboo lashings.
Figure 4.10: The first type of twine used loosened and broke too easily.
Size of the Support bamboo An extremely significant design and engineering flaw discovered was the importance of the bamboo for the platform support. The supporting bamboo must be of a similar diameter for a more secured lash. This prevents the overturning moment when the platforms are added and keeps the platform horizontal when extra weight is added.
50
Prototype Timelapse Video WIMAL documented the construction of the prototype bridge with a series of photographs which were combined into a timelapse video, followed by a demonstration of the platform additions being used.
Figure 4.11: Wimal Prototype Construction Timelapse and Demonstration Video.
http://www.youtube.com/watch?v=quEwMzx49yk
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MATERIAL
PREPARATION
1
3
4
2
5
6
PROTOTYPE
CONSTRUCTION
1
3:30PM
2
3:50PM
4:10PM
4:30PM
5
6
7
3:40 3:40PM
4:00PM
4:20PM
4:40PM
3 4
5 Implementation
5.1 Pilot Project In order to ensure smooth implementation of the bridge design, suitable villages within Ah Minh will be selected as test cases where information will be collected on the project’s success. Appropriate villages should have a significant number of single pole monkey bridges, few alternative safe transport options and a willing community. Once several villages are selected, a project representative will conduct discussions with the community and assess their willingness to participate in the trial. During these initial first meetings it is vital that strong ties of trust and understanding are developed. The representative will act on behalf of the project groups to explain and discuss the bridge additions. Any questions about the design will be answered to the best of the representative’s ability and any design alterations or additions that are suggested by the community will be recorded and reported back to the project committee for consideration. The representative, with the help of community leaders, will also select suitable test bridges. These bridges must: • Be single pole construction • Have at least one hand rail • Pass a brief structural overview Once complete understanding is achieved and the test bridges selected, the construction of the new design can commence. For the prototype village a construction team consisting of an administrator, an engineer and two construction personnel from the village will be formed. The administrators role will be to oversee the project , organise the purchasing of materials from local sources and act as liaison between the community and the project team. The engineer will work with the two personnel explaining the design and how it is constructed. The focus will be on ensuring that the construction personnel completely understand the design and can construct it unaided. Once all test bridges have been constructed, a representative will stay in the village for a month. In this time, they will record the success and failures of the new design. They will also educate the community on how to maintain the bridges as well as continuing to act as an ambassador between the community and project team. After the initial month the representative will depart and the trial of the bridges will continue over the following year. After a year the project team will return and assess the success of the bridges. Through open discussions with the community the likelihood of further implementation will be evaluated and if the project is considered a success, broader implementation will begin.
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5.2 Implementation Options Two different options for the construction and implementation of the bridge units in the villages have been considered. The first involves setting up a workshop with paid employees, while in the other option the bridge units are built and implemented by the end users.
5.3 Workshop Implementation Method Small workshops are set up in communities where platforms are mass produced as kits. These kits are then installed onto the bridges and maintained by employees. Funding will be provided for the initial set up of the workshop for the purchasing of tools, materials and the construction of the building however it is the aim of the project for the workshop to become self-sufficient off the income provided by the building of the bridge units.
Administrator The administrator’s primary role will to oversee the smooth running or the workshop. These duties include • Acting as a liaison between the community and project team • Financial administration • Purchasing of raw materials • Paying workers’ wages • Organisational paperwork
Construction Personnel The construction personnel are responsible for the manufacture of the basic components of the bridge units. This task includes: • Cutting Bamboo • Cutting wooden planks • Braiding bamboo rope • Striping green bamboo for lashing.
Installers The installers will transport the bridge materials to the site and install them in accordance to a manual. They will also perform basic structural tests to ensure the bridge is safe and ready to function.
Maintenance Personnel The workshop will also employ a specialty maintenance personnel whose task is to respond to specific
58
requests by the community to fix broken bridge units as well as performing general maintenance and checks on all bridges. Additionally when a bridge with units is being taken down it is their job to identify and collect any recyclable bridge units.
5.4 Instruction Implementation Method An implementation program is set up where the end users are provided with instructions on how to construct the bridge units independently. A project team of an administrator and engineers will conduct sessions demonstrating and explaining the main features of the design while assembling a demonstration bridge. Residents attending these sessions will be able to interact and discuss with the project team and will obtain a picture based instruction booklet on how to implement the bridges themselves. This implementation option is possible as all materials used in the bridge units are very easy to obtain in the Ah Minh district. Additionally the fabrication of the different parts is relatively easy and no special equipment is required. The aim of this independent method of installation is to encourage locals to take responsibility for the new bridge units. By installing the additions themselves onto monkey bridges immediately surrounding their dwellings a connection to the bridges is formed. This facilitates easier maintenance as the end users are more familiar with the bridges and can fix the bridges when problems arise. Users with also be encouraged to share their knowledge to willing neighbours. In this way the bridge design will continue to be implemented throughout the Ah Minh district and with continued monitoring by the project team widespread implementation will occur.
5.5 Implementation Comparisons Workshop Bulk buying of materials is more cost effective
Instruction Cheaper labour costs for end user as they are implementing it themselves and not paying for Platforms are built in controlled conditions by installation trained personnel, improving consistency and quality of the end product in comparison to Generates a stronger link between end users individual construction and the new bridge design as it forms a personal connection Platforms installed with more expertise by trained personnel Quality of construction techniques is maintained over time as information is not lost through the communication of instructions between locals in the Instruction Implantation method. Table 4: Comparison and Workshop and Instruction implementation method
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5.6 Project Costing Funding In order to reduce the initial start-up costs of the implementation of the bridge unit design for the end user external funding from charity organisations will be needed. WIMAL has identified likely charities to approach for funding assistance.
UTi Charitable Foundation UTi is a charity who focuses on improving the education, health, community infrastructure and housing in developing communities. In 2011 they funded and constructed two new bridges in the Mekong delta to enable children to travel to school safely and the communities to maximize the use of facilities. (UTi, 2012). In 2012 they were approached to fund and construct two new bridges in the Tra Vinh Province which will be used by a total of 29 000 people, to which they have agreed and construction will begin later this year. UTi’s interest in Vietnamese bridges makes them ideal to be approached by WIMAL for possible funding of the project.
Habitat for Humanity Habitat for Humanity is a non-profit ministry with the main focus of providing safe, affordable and sustainable housing to low-income families around the world. They are currently completing a project to increase access to water and sanitation facilities, alongside training in basic hygiene awareness to benefit the people of the districts in Kien Giang. Because they are already established in building houses and infrastructure in rural Vietnam, they would be an approachable organisation for funding.
Government Funding WIMAL will need to approach the government to discuss the details and legality regarding the project, as well as get permission to commence implementation. WIMAL would like to collaborate with the government on the possibility of incorporating the design solution with their current initiatives to improve local transportation. By doing so, the funding for the project could be subsidised for community by the government.
5.7 Project Costing Workshop Wage Costs The cost of wages will be funded by the income produced from the workshop. A typical Vietnamese labour cost is 120,000 to 180,000 VND (EWB forum) per day, which is approximately $6.50 Australian. Hence to decrease costs multiple job outlines can be covered by one individual.
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Table 5: Wage costs breakdown (EWB forum)
Administrator Construction and Installer Personnel Installer and Maintenance Personnel` Total
$7.00 $6.50 $7.50 $20
Equipment Costs In order to construct the bridge units basic equipment will needed for the workshop. These costs will ideally be included in the start-up cost of the workshop and covered by a participating charity organisation. Table 6: Equipment costs breakdown
Saw 4x Chisel Hand drill 6x Knife Total
$5.00 $10.00 $20.00 $10.00 $45.00
Workshop Building The cost of building the actual workshop will be the most expensive part of the project. As an approximate figure the cost to build a 40m2 house with a toilet was used. This costs approximately 65 million VND (EWB forum) or $3000 Australian. Ideally this cost will be covered by a participating charity outlined in Section 5.6 by employing a scheme such as Habitat for Humanity’s sweat equity building program. Total: $3000
Material Costs Table 7: Material costs breakdown
15x Bamboo units
$1.50
Acacia mangium Plank Bamboo Rope Total
$1.34 $0.10/m x 30 = $3.00 $5.84
Material Transportation In order for the bridge installers to transport the units to the different bridges the workshop will need to own a boat. The initial cost of purchasing a boat is $200 AUD (Jackson, 2009) and will be covered in the start-up cost funded by a charity organisation. Continual use of the boat will cost money as fuel prices are $1.18 AUD and using an approximately 2 litres a day total cost will be $2.40 and will be covered by the income generated.
Income In order to cover the cost of wages, fuel and the purchasing of materials the cost of outfitting a bridge would be set to approximately $14 dollars. This gives a profit margin of $8.16 from raw materials to pay for wages and fuel. Income can also be generated from the sale of excess rope and lashing produced.
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Total Start-up Cost Table 8: Total Start-up cost breakdown
Workshop building Boat Tools Total
$3000 $200 $45 $3245
Total Continued Cost per day Table 9: Total Continued costs per day breakdown
Wage Costs Fuel Costs Total
$20 $2.30 $22.30
Total Income 3 bridges a day = 3 x $8.16 = $24.48 Total Continued Cost per day = $22.30 Net Income = $24.48 - 22.30 = $2.18
Project Costing Individual Wage Costs The project team of an administrator and engineers will consist of volunteers therefore incurring no total wage costs. As the bridge units are also built, implemented and maintained by the end user and not a labourer no wages will be generated in the construction process either. Total = $0
Equipment Costs As the required equipment needed to construct the units are common tools, it is reasonable to assume that the locals will already own, or could borrow the tools. Hence there will be no equipment costs generated. Total10:= Equipment $0 Table costs breakdown 15x Bamboo units Acacia mangium Plank Bamboo Rope Total
$1.50 $1.34 $0.10/m x 30 = $3.00 $5.84
Material Transportation As the end users will individually obtain the materials transportation costs will vary between situations. However all materials are very common and locally sourced, so it can be assumed that the cost of transporting them to the final location will not be high. Total = $0
Total Cost of Outfitting Total = $5.84
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93+86 6+1G +14G Workshop
Startup Costs
Workshop Building Boat
Tools
Total Continued Costs Per Day Wage Costs Fuel Costs
5.8   Implementation sustainability
Both methods of implementation are self-sustainable after the initial set-up.
Workshop The workshop implementation method is sustainable by creating a cycle for demand for the platform attachments, expenditure, employment and income. This method is a boost to the economy and after the initial start-up costs, the workshop is only dependent on the people of the community to attend these workshops, and by doing so, provides the necessary funding to maintain this method of implementation.
Instruction implementation method This method of implementation empowers individuals or small groups to take responsibility for the safety of the monkey bridges. Because the materials are found locally, it is a small out of pocket expense to improve safety. The ease of attachment of the platform to the existing monkey bridge, as seen in the instruction manual at the end of the report, has the power to encourage future amendments to the other monkey bridges in the area.
6 Practical Consideration
There are many benefits for the community of Ah Minh if the bamboo bridges with the platform additions are implemented. In this section, the challenges of the design will be addressed along with possible solutions. Improvements in transportation have a wide range of positive effects on the affected communities, economy and the environment. These are advantages which would greatly outweigh the limitations.
6.1 Social Benefits The improvements in safety of the current monkey bridges will increase their usability in unfavourable conditions. Jobs and labour created from manufacturing and installing the platform components has to potential to boost local economy. Ideally, it would also widen the scale of communication between villages where the bridge attachments have been adopted as discussions on improvements or possible modifications will be conducted. Except for instances of extreme circumstances, the bridge will improve the ability for children and the elderly to cross waterways with confidence throughout the year.
Challenges The strength and effectiveness of the bridge attachments relies on proper installation. If proper techniques are not used when installing the platform pieces the positive benefits they provide will be negated. This is solved by implementing an education system for the manufacture and installation of the attachments. This education must be introduced slowly and take into account suggestions by the community in order to be effective. Proper construction and installation technique for both the attachments and monkey bridges will be discussed and taught by a team of project representatives and construction personnel from the village. The cost and effort required to install the platform units may be more important than an increased confidence in the bridge’s safety. However the fact that some communities have attempted to raise funds to build their own concrete bridges has shown that the villages are willing to take the initiative to increase safety independently.
6.2 Environmental Benefits The use of sustainable materials means that each bridge attachment will pose a low environmental burden on An Minh. Adapting to current monkey bridges will reduce the number of concrete replacements required. This will minimise damage to the environment that would otherwise occur through the importation of concrete and construction of the concrete bridges in rural areas.
Challenges WIMAL has estimated that the bridge attachments will need regular maintenance. This means that the upkeep for the add-ons is dependent on the environmental conditions and regularity of use through the attachment’s lifetime. Resource usage will change for each bridge and hence 65
environmental benefits will vary. However, the ability to recycle the dismantled monkey bridges and the acacia mangium planks improves the sustainability of the unit’s service life.
6.3 Economic Benefits The labour workforce and income created from the manufacture and implementation of the bridges will increase the wealth of communities and improve the overall standard of life in the regions it is installed in. The attachments will also keep a larger number of citizens satisfied and the implementation plan is combined with the current Vietnamese government initiatives by the Vietnamese government. This is more economically stable and viable than concrete bridge replacements being implemented by themselves. The bridge attachment will allow for more farmers to transport their goods across waters without the need for more expensive modes of transport, especially in more rural areas. WIMAL’s project shares the same ideals are the government schemes – increasing safety while also creating labour and jobs for communities. It is unlikely then that the government will see the bridge attachments as undermining their concrete replacements. Rather, they will see them as a method of supporting their developments by increasing the safety of bridges where it is not economically feasible to implement concrete bridges, or as a temporary solution while gradually implementing concrete bridges.
6.4 Maintenance Maintaining the bridge attachments is extremely simple. In the different implementation methods discussed, different maintenance programs are used. In the workshop implementation method an employee is responsible for inspecting and ensuring the bridge attachments are structurally sound and still functional. In the individual implementation the end users who installed the attachments to bridges near their dwellings are responsible for regular maintenance. Some aspects of the bridge attachments will need regular maintenance: • The lashings between the platform, support pole and handrail will need regular tightening depending on the frequency of use. While the bamboo lashing used will shrink over time, constant use will still loosen the ropes slightly. • The platform surface may become worn down from constant weathering and use. They can simply be replaced by new platforms; however, replacements will not be required often as acacia mangium has a long service life.
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6.5 Future Improvements Further improvements could be potentially made to aid the implementation of the bridge attachments. Currently, the bridge add-on imposes increased turning moments on the handrail and support pole. For less structurally sound monkey bridges, added supports at the handrails and the X-frame joint could be used.
Handrail Supports For the handrail supports, a few simple improvement ideas were conceived. The main function of these supports is to prevent excessive bending along the span of the handrail. This can be achieved in several ways: • A second handrail could be added to reinforce the first. • A simple cross brace could be added at each corner to prevent downwards bending. • Reinforced lashing at the connection points between handrail and support columns.
Added weight from the additional platforms could cause the existing lashed joints to slip down the supporting X-frame poles, as shown in Figure 6.1.
Figure 6.1: Movement of handrail lashing due to added weight.
The additional force from the supporting ropes transferred to the handrail could cause bending of the bamboo, leading to eventual failure or permanent deformation of the bamboo beam which would cause loosening of the supporting ropes.
Figure 6.2: Bending of the handrail caused by the added weight of the platform addition
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Bamboo Beam The turning moment about the support pole is mostly prevented by the ropes connecting the platforms to the handrails. However, in the case of rope failure, additional supports can be added. • Reinforced lashing at the connection point between support pole and X-frame. • A set of two bamboo posts drilled vertically into the support pole to ‘clamp’ the support pole between the X-frame and prevent movement. • A support post, lashed to the X-frame, can be drilled into the support pole. While this is not ideal as drilling decreases bamboo integrity, this method would only be used as a last-resort of bridge support in case of total rope failure. These joint reinforcements, if required, would be manufactured in the same workshops as the bridge add-on parts. Ideally, the platforms will be able to be sold and installed as a one-off product without the need for additional support. However, residents who desire added strength or whose bridges are not fully structurally sound can request these extra reinforcements to improve bridge safety.
The turning moment caused by the additional weight of the platform (Figure ) could cause potential loosening of the lashing of the bamboo pole at the X-frame.
Figure 6.3: Turning moment around support pole
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6.6 Feasibility Table 11: Feasibility table of costs
Material
Cost *
Bamboo Pole
0.302 AUD/m 47.5 AUD/ m3 $0.10 AUD/m Total
Acacia magnium plank Bamboo Rope
Cost per unit (AUD) $0.10 $0.09
Cost per 15 Percentage of average Source units (AUD) monthly income ** $1.50 8% Local Farmers $1.34 7.3% Local mills
$0.20
$3.00
16%
$0.39
$5.84
31.3%
Workshop
* EWB Forum 2012 ** 2010 Vietnam poverty line of 400,000VND per month per person used.
6.7 Strength Calculations
T
O(y)
F 20
Weight Force
50
60
50
Weight Force of Attached Bamboo: 5.66N Weight Force of Platform: 22.1N Weight Force of live loading: 981N
θ=75°
Max Tension in Bamboo Rope: T<1.25 x 104 N Actual Tension in rope: Ox = 3530 N Oy = 128 N T = 913 N
Conclusions:
W1
W2
Figure 6.4: Free body diagram of the bridge sections.
Since the tension is shared over two ropes the tension in each rope will be half thus T = 457 N. Therefor as 457 N < 1 2500 N the maximum tensile stress of the rope is well above the calculated value thus the rope failing due to excess load is very unlikely (See detailed calculations in Appendix F)
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7 Ethics
The following considerations, recommendations and possible solutions comply with the Australian Code of Ethics, found on the Engineers Australia website.
7.1 Demonstrating Integrity Act on the basis of a well-informed conscience Through thorough background research, WIMAL aimed to avoid cultural insensitivity that could occur through ignorance. This primary consideration enabled the well-informed decision making process during the design review and selection.
Be Honest and Trustworthy Other difficulties predicted during the implementation of the platform additions to the monkey bridges would include receiving feedback, criticism and total resistance towards an external design. This should be resolved through discussions and involvement of the end users in the production, manufacturing and implementation of the platforms. This is ideal as they are the most qualified in construction techniques of monkey bridges and any input about the design would be highly useful. If these discussions do not take place, potential improvements could be overlooked, which is a backwards step from WIMAL’s goals to improve the safety of these bridges.
Respect the dignity of all persons All the design decisions which have been made so far have been based on the research information on Kien Giang province and of current transportation issues based around monkey bridges. The application of the schemes to introduce the platform addition and to ensure safe construction may be perceived negatively as undermining the current bridges and the users confidence in being able to traverse across the bridge daily. Furthermore, though safety is vital, applying external OH&S requirements, such as wearing harnesses, could go against traditional methods. Any form of offense should definitely be avoided through open communication during implementation.
7.2 Practice Competently Maintain and develop knowledge and skills To further improve the design, critical feedback and contributions were taken into account, such as extrapolating on the selection criteria and providing more details on the other designs. This process should be mimicked throughout the implementation to ensure that the addition is modified to satisfy the affected community.
Represent areas of competence objectively The design has attempted to take into account the turning moments of the platforms but the combined weight of the platforms on the bridge might compromise its stability. It is encouraged that structural tests are run on the design by the Vietnamese government. Additionally through collaboration with local experts the effects of implementing the design onto the current bridges is investigated and any problems solved. 71
Act on the basis of adequate knowledge The connections would apply the existing method of lashing that is currently used to construct the monkey bridges. By using the specialised skills of the Vietnamese people the design will be implemented easily and successfully, as well as facilitating the development of possible improvements.
7.3 Exercise Leadership Uphold the reputation and trustworthiness of the practice of engineering WIMAL wishes to work with government initiatives to improve Vietnam’s transportation system. If it is recognised and agreed upon that replacing smaller bridges in less populated areas is no economically viable, WIMAL wishes to collaborate with the government to implement the platform design. Negotiations with the government can be made to confirm which bridges they shall be replacing to more efficiently install the platform to monkey bridges that will not be replaced.
Support and encourage diversity The mechanisms of installing the add-ons are extremely similar to the methods used to construct the existing bridges. This allows leadership roles and decision making as to how and where they would like to implement the design to remain within the community.
Communicate honestly and effectively, taking into account the reliance of others on engineering expertise WIMAL will clarify the costs of the platforms to the community so well-informed and communal decisions can be made as to whether installation will proceed. The Vietnamese bridge builders are highly experienced and will be able to provide WIMAL with engineering expertise.
7.4 Promote Sustainability Engage responsibly with the community and other stakeholders Engage with the community to ensure they are content with the installation of the bridge. Through inclusion they will be more willing to adapt and modify it to ensure the design is sustainable in the later years.
Practise engineering to foster the health, safety and wellbeing of the community and the environment The aim of the design was to improve the safety of the community using the monkey bridges. The implementation of the design has very little environmental and health impacts. The materials are locally grown. Improvements in community morale will be made by providing jobs and a sense of security.
Balance the needs of the present with the needs of future generations The service life of the platforms are essentially the same as the bridge. This, can be reassessed when a monkey bridge is deemed to be unsafe and must be demolished in order to build another one. In these instances, the platforms can be recycled. The future generations may not have to pay for 72
these platforms or they may develop even safer alternatives to the monkey bridges. The additional materials can be left to decay with the bamboo without any detrimental environmental impacts.
Sustainability WIMAL has created a design that can be modified by the users over time with to adapt to the changing circumstances of the community. To maintain the project, the community should have the skills and desire to maintain, and possibly even expand, the implemented solutions and the knowledge needed to solve future problems that arise.
Environmental Sustainability The bamboo stalks and lashings used to construct the current monkey bridges are locally sourced, and is easily grown and harvested. Bamboo grows rapidly in this climate, taking only 5 years to reach maturity compared to an average of 75 years for wood. To maintain consistency of the materials used, bamboo was also used as a part of the platform additions. However, due to the inefficiency of producing planks from bamboo, WIMAL concluded from the research completed that acacia magnium wood was the best alternative as they are equally as inexpensive and are already grown locally. Furthermore, the bamboo bridges being replaced by concrete bridges can be recycled. They can be cut into 30cm sections. The acacia planks, which have a longer lifespan than bamboo, can be recycled between bridges.
Social and Cultural Sustainability By minimising the external aspects of the platform addition, it will be easier for the community of Ah Minh, and other rural communities that will have the design implemented, to accept the design, and feel a connection and security in the new design.
Economical Sustainability Using locally sourced materials promotes the economy by initiating the farming and manufacturing of these bamboo poles and acacia planks. This also reduces transport time, thus increasing the efficiency of the implementation of the platforms.
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8 Conclusion
The safety of current ‘monkey’ bridges is a significant problem in rural Vietnam. During the monsoonal season, these bridges become almost unusable due to the difficulty crossing wet bamboo as it is near impossible to balance across a thin, slippery bamboo beam over a raging river on the way to work or school each day. Current government initiatives to replace wood and bamboo bridges with concrete alternatives have been partly successful, but funding is unstable and the sheer number of existing monkey bridges means that replacing them all is economically difficult. Our design process regarded various aspects of Vietnamese culture and existing bridges, taking into account cost, culture, environmental sustainability and safety. A number of alternatives were considered including demolishing the existing bridges and building new ones. The current platform design was chosen primarily due to its cultural sensitivity, and its ability to be easily implemented onto the current monkey bridges across An Minh and surrounding Vietnam. The simplicity of the design means that it will be low cost, easily installed and adaptable to a wide range of existing bridges. Moving forwards, we are planning to reconsider and develop the design of the platform additions. This may be in the form of reducing the number of parts that must be attached to the bridge to aid installation, or possibly making the pieces easily removable to improve adaptability. Additional attachments are also being considered to improve the safety and strength of the monkey bridges. Due to the additional stresses introduced by the platform additions, ways to reinforce the handrail and main bamboo beam have been examined. By incrementally modifying a culturally significant design, rather than radically changing it, we believe that our project could be very easily accepted into Vietnamese society. Additionally, WIMAL’s implementation plan not only increases the safety of bridges, but the wealth of local villages. This sustainable model will allow the manufacture of attachment pieces to become integrated with small villages, creating job opportunities and further demand for skills needed for future construction jobs and labour. This addition will provide a safer and more reliable method of crossing the rivers for the men, women and children of Vietnam but especially the elderly to cross without fear of falling. Improving the mobility of the elderly will significantly improve the lives of the aging Vietnamese population by enabling them to have greater access to the rest of the community and village. Pedestrian transportation safety is something that most Australians take for granted. We cross numerous elevated walkways, stairs and bridges each day without ever thinking of whether we may fall, hurt or even fatally injure ourselves. This problem is faced multiple times a day by the people of An Minh, with children crossing bridges every day to and from school that would never be permitted in Australia without safety harnesses. Unfortunately this is seen as a necessary risk in Vietnam. WIMAL’s design solution will significantly reduce the risk and thus reduce the number of bridge related fatalities and incidents each year. It is our priority to increase the confidence and standard of safety of those who live in the area where the platform attachments are to be implemented. WIMAL is committed to ensuring the safety of Vietnamese citizens by producing an affordable and sustainable solution to their monkey bridges. - WIMAL 23 October 2012
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9 Reflections
From left to right: Lasath, Isobel, Wenray, Amara, Matheesha
Team Reflection The team members of WIMAL were acquaintances prior to beginning the project. However, the EWB challenge was our first group work project together, and progressing through the design process, completion of the report and construction of the prototype has taught us all valuable lessons in teamwork, time management and effective communication. It was initially decided that group meetings were to be held every week. However, outside class, the most effective and efficient form of communication between the members was using Google drive as a common place to share and store documents, and Facebook groups to discuss and plan our meetings and work. This communication system established an open atmosphere to ensure that everyone had access to the same information and freedom to communicate their own ideas, join discussions, and question or clarify plans. Other posts included to-do lists with tasks assigned to individual members to be completed by a given deadline, links to finished documents, precedent research of designs for inspiration, and uplifting and motivational media. As a group all studying engineering and architecture, the area of transportation and improving current monkey bridges in the An Minh region was a natural choice. The early weeks of semester, however, were spent brainstorming wacky ideas for a new, innovative bridge. In hindsight, while this time could have been spent more productively, the more radical designs really made us see the sheer advantage of our final, simpler proposal. Conflicts still arose when deciding on our design idea. These difficulties stemmed from our attempt to remain as true to our objectives of creating a cheap and functional alternative to the monkey bridges but still adhering to the cultural and traditional impression as possible. It was eventually accepted that practicality took first and foremost priority as we all hoped the design could be realistically implemented. However, as the design was developed further, we all agreed that it met the aesthetic standards that we had desired. The personal profiles that were completed at the start of the semester showed that our team was strongest as finishers. On paper then, the odds were against us in this respect, however we did not think much about it at the time. As the semester progressed though, it soon became evident that these profiles were surprisingly accurate. However, through the rushed finish of our initial report, individual strengths and weaknesses of each member became apparent. Tasks were assigned according to our skill level in research, drawing and editing to complete the report. Isobel, the team leader and project manager, ensured the equal distribution of work with tasks assigned according to our preferences and skill level in research, drawing and editing to complete the report. She remained the most practical throughout the selection criteria of the multiple proposed designs and was extremely determined to ensure that our solution could be implemented and lead to be self-sustained by the community.
Isobel - Team Leader Isobel provided guidance and direction throughout semester and helped overcome any
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difficulties that arose. Her level-headedness and determination to create a realistic solution helped us achieve our final result.
Lasath - Design Director Lasath took on the responsibility of a design director and finalised the design of each solution that we came up with. He made sketches, diagrams and tables of the positives and negatives of the mechanism of each design to make the selection process more straightforward and fair.
Wenray - Technical Guru Wenray, our technical guru, managed the format and layout of the proposals, presentation slides, and reports using a variety of software, such as Adobe Photoshop, Adobe Lightroom, Adobe Illustrator, Adobe InDesign, Google SketchUp and Rhinoceros in collaboration with Lasath.
Matheesha - Drafter/All rounder When the final design solution was settled on, technical drawings and calculations were completed by Matheesha. Matheesha also aided in completing many important components of the report.
Amara - Editor/Researcher Amara was the main editor of the written documents and investigated the context and background in which our solution was to be implemented to ensure the feasibility of our design. The prototype construction was a difficult but satisfying task. Setting a time for all members to be present for the construction was the most difficult obstacle, especially as we underestimated the time required. We spent 3 days of intensive labour to complete the prototype, utilising a workshop to cut up the bamboo pieces and planks, lashing the components together, and constructing a 3 plank section of our amended monkey bridge. Trial and error was involved in finding suitable twine for lashing and maintaining the structural stability of the section of our design. Working through these challenges was definitely a team bonding exercise. Overall, the EWB challenge has been a memorable experience for us all. Overcoming conflicts and challenges has brought us closer together as friends as well as engineering colleagues.
- WIMAL
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Personal Reflections Advanced Engineering has been an eye opening experience – looking back on the EWB challenge, I’ve not only learnt a lot about the field of engineering, but also about myself. The subject felt a bit out of left field. Amidst all the maths, equations and logical thinking suddenly came a single subject which combined these problem solving skills with creativity, and I loved it. At the beginning of the semester, however, the thought of starting from scratch to solve a thirdworld problem was quite overwhelming, but I was eager for the challenge. I was quite intimidated at the sheer scale of past reports, especially as the direction we would take still seemed unclear. At this point, the subject still seemed like any other compulsory class. I found creating an initial design to be the most difficult part of the project, so the turning point for me came when we arrived at a much simpler final design idea. Instead of the pressure to create a complicated, innovative solution, we were able to focus on actually making an idea come to reality. Here I saw advanced engineering less as a subject and more of self-fulfilling exercise. The idea that our group could possibly be selected to represent the university in the EWB competition really motivated me to help achieve the best result for the group. Seeing our design come to life in the working prototype was one of the highlights of semester. It was fantastic to see the sheer variety of projects and talent between groups really served as a reminder to me of the possibilities the future could hold for us engineers and the diversity of the different paths we can take. The subject definitely increased my passion for engineering, and really made me less ignorant of the vital considerations involved with humanitarian engineering such as ethics and cultural conflicts. As the ‘technical guru’ I helped format the report, create the 3D models of the design, and research background information and implementation issues. This role suited me perfectly - with a background in architecture too, I really enjoyed putting the final result together and also the aspect of aesthetics involved with our report - from what I learnt in architecture, the presentation of your ideas is just as important as the quality of content itself. I was blessed with an amazing group, and we really connected well from the outset of the project - our personalities and individual skills and talents complemented each other well. From my point of view, there was very little disagreement at all during semester and communication between members was fantastic - any ideas were readily discussed and I could freely express my own opinion at any time. The new friendships I have formed this semester are priceless (even though there were moments where we realised that we were becoming gradually crazier in each other’s presence) and I am so glad for the journey. It was incredibly satisfying to formulate a design from scratch and work on something that would also be conducive for the future. Looking back at how far we’ve come, I’m so proud of our group’s efforts and I have no regrets. All the late nights and work involved were, in the end, trivial when I reflect on the final result – it was all worth it. - Wenray Wang 79
The EWB challenge has been an amazing and highly educational experience, and has contributed to Advanced Engineering being one of my most enjoyable subjects this semester. Although the workload was huge it was never overwhelming because of the willingness of everyone in my team to go far beyond what any of us thought possible at the beginning of the semester. Although we did not decide on specific roles at first, as the challenge progressed everyone slowly gravitated towards their personal strengths. I assumed a leadership role as it became my responsibility to ensure the project was kept on track. This was highly challenging due to the sheer number of tasks and documents that had to be recorded and organised. In order to ensure nothing was forgotten, I created detailed lists of tasks that needed completing and parts to be improved, and sections were divided among team members. At first I was hesitant to take on the leadership role as I didn’t want to be the person always telling everyone what to do and when to do it. However one of the most important lessons this project has taught me is that leadership isn’t just about assigning people work and making deadlines. It’s about discovering the strengths of each team member and making sure that the work they are doing is what they enjoy. By ensuring the design elements such as creating graphics and organising the layout were covered by Lasath and Wenray, while the main content of the report was written and edited by Amara and Matheesha everyone was engaging in tasks they were comfortable with, and our teams productivity greatly increased. This challenge has also taught me the value of an amazing group. Before this semester I much preferred individual assignments over group work as my previous experiences with group work were largely unproductive. However with WIMAL it was virtually the opposite, because we worked so well as a team and freely communicated, everything was completed faster than I often felt possible. Additionally the project has highlighted the importance of respect and friendship within the group. This respect and familiarity meant that everyone was comfortable bringing their ideas to the table and honestly critiquing others. Although this sometimes lead to heated debate, these honest conflicting opinions enabled us to further refine our concept and ultimately lead us to our final design. The EWB challenge has also widened my perception of what an engineer can achieve, and how through their designs, they can help improve the lives of others. Along with the benefits of humanitarian engineering, there are also challenges, and this project has particularly emphasized the difficulties that can be encountered when trying to implement a project in a foreign country. In our perspective some of our preliminary designs seemed like the perfect solutions, however a variety of factors made them overall impractical for implementation in Vietnam. This was further reinforced through brain storming sessions where we considered all the different ethical and practical problems that could arise because of the differences in Vietnam’s and Australia’s cultures. Overall the EWB challenge has been an incredible experience and although demanding at times, the final result has been well worth it. We didn’t just end up with an extensive final report and working prototype, but I also gained a greater sense of leadership, a renewed eagerness to become an engineer, and a strong group of friends. 80
- Isobel James
Before starting this challenge I was blissfully ignorant on how much time and effort that I would have to put in to this subject, thus I underestimated the toll that the 10 or so weeks of working on this project would take on me. Saying this however, undertaking the EWB challenge has been a thoroughly rewarding experience increasing my awareness of our role as humanitarian engineers. It has prompted me to get more involved in EWB activities and highlighted that the ‘calculations’ (number crunching) part of engineering is a necessary but relatively small area in engineering. It has been one of the most enjoyable, practical and worthwhile engineering courses that I have enrolled in. Being a team project had its challenges and triumphs as we attempted not to compromise to get a solution but to apply our own unique skill sets to collaborate to get one. As all of the members of our group were friends beforehand we all knew each other’s strengths and weaknesses making it easier to delegate the tasks. This was a real advantage as we could get started much quicker and had open lines of communication between all of us (phones, Google docs and a Facebook group). Funnily enough the greatest group ‘conflicts’ occurred on the aesthetics of the design, report and prototypes. Although as a group of Architects this was not unexpected. Delegated the primary role of draftsperson/technical drawer of the final design; I was in charge of turning our design ideas into a physical reality. During our initial conceptual design phase, the design was chopping and changing rapidly, thus the primary mode of communication of our concepts was through quick 2 minute hand sketches. This worked very efficiently until we had a general consensus on our final design which required the drawings to be more concrete. This is where CAD drawings were used. Continuous updating of the drawings was the most laborious tasks, but was also one of the most vital as they were our only representation of what our bridge looked like until our prototype. I think all of our team entered the challenge with the mindset, “this project will never be actually implemented” however as the weeks wore on and our design became clearer and tangible we found ourselves thinking that “hey, this actually might work!” Without even realizing it we found that all of our professional, communication and engineering skills improved dramatically. Our group dynamic was amazing which allowed us to enjoy the experience and become much closer friends. Currently studying in my second year of university I was still unsure on what I was looking for in my career. Engineers can do really cool stuff like try to find life on Mars and discover the Higgs boson, but they can also help people to have basic human rights. Both of these areas are important but the later can be solved with low-tech solutions that we already have, all that is needed is the right people in the right place. This challenge has significantly changed my view on what I want to do as an engineer and by prompting me to get more involved in EWB I feel that I have discovered a real passion for humanitarian engineering. As such I am truly grateful in undertaking the 2012 Engineers Without Borders Challenge. - Matheesha Gunaratne
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Through the processes of completing the Engineers Without Borders (EWB) Challenge 2012, my perceptions of the roles and responsibilities of engineers has been redefined. I enlightened to the true value of team work and how I can apply the knowledge gained through my studies to assist a wide scope of people. Before this semester, I had never heard of humanitarian engineering, let alone envision myself as a part of a team to assist in the development of the Ah Minh district by providing a possible design solution that has could be realised and implemented. I found that my experience in design and the associated processes, from having completed a year of architecture prior to participating in the EWB Challenge, has really assisted in presenting the teamâ&#x20AC;&#x2122;s design solution effectively. I was able to easily transfer ideas of individual group members to diagrams in the initial stages of approaching the challenge. This helped to communicate the mechanics behind the ideas between members of WIMAL, and when the others understood it, they were able to further develop the radical ideas which evolved into more practical solutions. The biggest challenge was the emphasis on a community reactions, cultural sensitivity and ethics. These were new concepts and considerations that I have never had to focus on before, and I think everyone else struggled as well. The members of WIMAL were acquainted prior to participating in this project, however, it was the first time working as a group together. We had similar strengths with creating possible solutions but this became a weakness when we had to agree on the final design because there were many conflicting ideas. This was overcame by slowly researching (we were easily side tracked by Facebook, Youtube and food) and agreeing on the best option to meet our shared goals of providing the functional and practical design solution that was set at the beginning of the EWB Challenge. While there were some late nights, weekends at university and touching up in the mornings of the due date, I believed the team functioned every effectively. We trusted each other to meet deadlines and contribute equally and none of this had to be reinforced. My strengths lay with researching and transforming my research and the research and ideas from other members into relevant content. However, at one point I became extremely pedantic about editing and I was working inefficiently. Isobel had to assist me to ensure the report maintained cohesive as other members added to it and culling certain sections out. The most stressful aspect throughout the EWB Challenge was my fear of letting the team down. I would not been able to make it through the course of this semester without the support, encouragement and contagious enthusiasm of the other members of WIMAL. Tasks like generating ideas for possible design solutions, completing reports and producing such a high quality of work would not have been a possible feat alone. I look forward to working with them again if possible in the future years of our degree and to further develop our friendship. I am extremely thankful for constructive feedback and inspiration provided by our mentors throughout this course. - Amara Kruaval
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In hindsight, doing the EWB Challenge has left me physically and mentally drained, yet at the same time Iâ&#x20AC;&#x2122;m delighted that I took part in something meaningful with the potential to help a community in An Minh to improve their quality of life and hopefully save many lives too. Initially, the task of producing a report as thick as a textbook seemed daunting, yet through delegating tasks and roles, the job seemed a bit easier. As Design Director, my role was to finalise the proposed design and develop a method in which we could select the best design that met our design criteria. These design solutions came from our many brainstorming sessions, some of which (mostly my ideas) were upon reflection, stupendously ambitious. As a part of my role, I produced many diagrams and figures. This played to my strengths as I come from a graphic design background. However the actual formulation of a report (and writing this statement) is where I found my greatest weakness. I have always had trouble translating my thoughts and ideas into words, an issue that I find incredibly frustrating and need to be addressed! I also collaborated with our editor Amara to produce the prototype section of the report, documenting the problems and the steps taken to produce it. Additionally I helped our technical guru Wenray to produce the final layout and design of our report. Undergoing this challenge and producing the report heavily shaped my thinking of what engineering is and what professional engineers can achieve. It exposed me to the magnitude of ethical, cultural and environmental considerations that have to be made to ensure that a project would be successful. Also the level of interaction required between engineers and the stakeholders of a project was completely different to what I had imagined. I found that this aspect of the project enriched my passion for design and engineering. Additionally doing this project was a real eye-opener to the problems faced by people living in developing countries and what we as engineers could do to help. In its entirety, I believe our report was truly a group effort - each team member helped one another with his or her assigned role. The fact that we were already such good friends did make the task a lot easier. We knew each othersâ&#x20AC;&#x2122; strengths and weakness and could assign roles and select a team leader to reflect our capabilities without any awkward power struggles occurring. Yet there was the occasional (a lot to be frank) of conflicts in trivial matters in regards to design between our team leader and me. However, the group work aspect of this project helped me identify another weakness of mine, which is communicating ideas effectively. Also I found that doing the project (especially making the prototype), with its up and downs, has made us even closer as friends. Undertaking the EWB Challenge has been a worthwhile and valuable experience for me, helping me identify my weaknesses and giving me a platform to improve them. More importantly it has revealed to me a side of engineering that I wasnâ&#x20AC;&#x2122;t aware of before and has exposed me to the harsh reality of life some people face. - Lasath Siriwardena
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10 References
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<http://www.mekongbamboo.org/images/stories/video/Bamboo_resources_report_in_7_provinces_ of_Southern_Vietnam_by_IPSARD.pdf> J.W. Tumbull. H.R. Crompton and K. Pinyopusarerk, (1997) Recent Developments in Acacia Planting Jackson, T (2009) Wooden Boat Magazine, Vietnam Boat Project Serves Multiple Goals. The Degenhardt Foundation. Accessed 5th October 2012. <http://www.aidforkids.org/press/ woodenboat.html> Jassen, J. (2000) Designing and Building with Bamboo. International Network for Bamboo and Rattan, Netherlands. <http://www.inbar.int/publication/pdf/INBAR_Technical_Report_No20.pdf> Jones, L. Rogers, D. Toder, E. (2000), ‘Economic Consequences of an Aging Population’, Urban Institute. Accessed 30 August 2012, <http://ww.urban.org/publications/310237.html> Kampot Fisheries Cantonment. (2009) Importance of Coastal Ecosystems and Resources in the Transboundayr Waters of Kampot and Kien Giang Provinces. Accessed 11 September 2012, <http:// www.unepscs.org/Lessons_Learned/Files/South-China-Sea-Transboundary-Water-Lesson.pdf> Li, X (2004) Physical, Chemical, And Mechanical Properties Of Bamboo And Its Utilization Potential For Fiberboard Manufacturing. Beijing. http://users.telenet.be/jeffstubbe/thesis/documenten/papers/ PHYSICAL,%20CHEMICAL,%20AND%20MECHANICAL%20PROPERTIES%20OF%20BAMBOO%20. pdf Liese, W. (1992) The Structure Of Bamboo In Relation To Its Properties And Utilization. Germany <http://www.emissionizero.net/W._Liese_-_The_Structure_of_Bamboo.pdf> Long, G. Pfau, W. (2007) ‘The elderly population in Vietnam during economic transformation: an overview’, Munich University. Accessed 30 August 2012, <http://www.grips.ac.jp/vietnam/VDPTokyo/ Doc/SocialBook1Chapter7-1.pdf> Long, G. Pfau, W. (2007) ‘The elderly population in Vietnam during economic transformation: an overview’ , Munich University. Accessed 30 August 2012, <http://www.grips.ac.jp/vietnam/VDFTokyo/ Doc/SocialBook1Chapter7-1.pdf> Mackay, P. Russell, M. (2011) Socialist Republic of Vietnam: Climate Change Impact and Adaptation Study in the Mekong Delta. Accessed 14 September 2012, <http://www2.adb.org/Documents/ Reports/Consultant/VIE/43295/43295-012-vie-tacr-01.pdf> Marsh, J. (2008) Industrial Bamboo in Nor th West Viet Nam and Nor th East Lao PDR. Accessed 2 October 2012, <http://www.value-chains.org/dyn/bds/docs/597/ ProsperityInitiativeIndustrialBambooNWVietnamNEL.pdf> Midgley, S. (2007) Tropical Acacias: Their Domestication Ano Contribution To Asia’s Wood Ano Pulp Industries, Salwood Asia Pacific Pty Ltd, Canberra. Accessed 10th September 2012, <http:// biblioteca1.infor.cl:81/DataFiles/26491.pdf> Nguyen, K. (2005) Common Vietnamese Beliefs. Accessed 11 September 2012, <http://www.
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vietspring.org/religion/beliefs.html> Nguyen, V. et al (2005). Study of Geological Structures of MEKONG RIVER BANKS BY GROUND PENETRATING RADAR: FORECASTING AVULSION–PRONE ZONES, National Centre for Natural Science and Technology of Vietnam, Hanoi. Accessed 14 September 2012; <http://agp2.igf.edu.pl/ agp/files/53/2/Nguyen_et_al.pdf> Orange Partners. (2012) Environment and Society. Accessed 15 September 2012 <http://www. orangepartners.com.sg/blog.html#> Proceedings of an international workshop held in Hanoi, Vietnam, Australian Centre for Agricultural Research, Canberra. Accessed 10th of September 2012, <http://aciar.gov.au/files/node/13704/ recent_developments_in_acacia_planting_part_1_14703.pdf> Quoi, L. (2010) Vegetation cover in Kien Giang Province, Department of Science of Technology, Kien Giang Province <http://kiengiangbiospherereserve.com.vn/project/uploads/doc/quoi_report_kgbr_ landcover_2009_en.pdf> Rottke, E (2012) Bambus, Rwth Aachen. Faculty of Architecture, Aachen. Accessed 8th of September; <http://bambus.rwth-aachen.de/eng/index.html> Sahaya International, (2012) Vietnam Housing & Education Project – Kien Giang. Accessed 11 September 2012, <http://sahaya.org/vietnam.html> Saigon Giai Phong Online, (2012) Will delete all the bridges in the Mekong Delta in 2015. Accessed 10 September 2012, <http://www.sggp.org.vn/thongtincanuoc/2012/3/283416/> Sawadee, (2002) Kien Giang. Accessed 11 September 2012, <http://vietnam.sawadee.com/ kiengiang/index.htm> Sein, C. Mitlöhner, R (2011) Acacia mangium Wild, Ecology and Silvaculture in Vietnam. CIFOR, Indonesia. Accessed 10th September 2012, <http://www.cifor.org/publications/pdf_files/Books/ BCIFOR1105.pdf> Sein, C. Mitlöhner, R (2011) Acacia mangium Wild. Ecology and silviculture in Vietnam. CIFOR, Indonesia. Accessed 10th September 2012, <http://www.cifor.org/publications/pdf_files/Books/ BCIFOR1105.pdf> Te, H.D. (2012) Religion of the Vietnamese. Accessed 11 September 2012, <http://www.vietspring. org/religion/religioninvn.html> TechInfo Vietnam. (2008) Design Estimates Comments. Accessed 14 September 2012, <http:// pontvk.org/chuong-trinh-xay-cau/thiet-ke-cau/gop-y-thiet-ke-du-toan> Thanh Nien (2012) Vietnam average monthly wage rises to $185. Accessed 14 September 2012, <http://www.thanhniennews.com/index/pages/20120125-salaries-rise-in-vietnam-income-gap-stillwide.aspx>
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The Mekong Delta Economic Corp. (2010) ‘Kien Giang Province’. Accessed 8 September 2012, <http://www. mdec.vn/index.php?option=com_content&view=category&layout=blog&id=131&Itemid=239> Tinmoi. (2012) Gai Lai: Hazard by River Bridges. Accessed 8 September 2012, <http://www.tinmoi. vn/gia-lai-hiem-hoa-qua-song-bang-cau-khi-08815732.html> Tomek, V. (2006) Environmental Concerns – Buddhist Responses. Accessed 12 September 2012, <http://www.religioustolerance.org/tomek20.htm> Trung, N. (2008) Melaleuca Timber; Resource Potential And Its Current Use In Kien Giang Province. Deutsche Gesellschaft fuerTechnische Zusammenarbeit, Germany. Accessed 9th September 2012, <http://kiengiangbiospherereserve.com.vn/project/uploads/doc/4.melaleuca_potential_and_its_ current_use_in_kg_-_trung_e2008.pdf> VietBao, (2012) Watch the bridge “the world’s most feared” spread across the Mekong Delta. Accessed 9 September 2012, <http://vietbao.vn/Video-clip/Ngam-nhung-cay-cau-dang-so-nhatthe-gioi-rai-khap-DBSCL/2131518395/601/> VietBao. (2004) Remove bridges projects in the Mekong Delta: Start slow because of low capital. Accessed 8 September 2012, <http://vietbao.vn/The-gioi-tre/Du-an-xoa-cau-khi-o-DBSCL-Trienkhai-cham-vi-von-it/40016110/275/> Vietnam Business Forum, (2012) Kien Giang Fisheries: Developing Industrial Agriculture. Accessed 11 September 2012, <http://vccinews.com/news_detail.asp?news_id=2671> Vietnam News, (2012) Delta farmers face shortage of saline-resistant seeds. Accessed 11 September 2012, <http://vietnamnews.vnagency.com.vn/Agriculture/229594/delta-farmers-face-shortage-ofsaline-resistant-seeds.html> Vietnam-Culture.com. (2006) The Viet Ethnic Group. Accessed 11 September 2012, <http://www. vietnam-culture.com/viet.aspx> Vietnam-Netherlands Mekong Delta Masterplan project, (2011) Mekong Delta Water Resources Assessment Studies. Accessed 14 September 2012, <http://wptest.partnersvoorwater.nl/wpcontent/uploads/2011/08/WATERRESOURCESfinaldraft.pdf> Vietrade (2012) The social-economic development overall of Kien Giang Province to 2020 – Part 1. Accessed 11 September 2012, <http://www.vietrade.gov.vn/en/index.php?option=com_ content&view=article&id=1202:the-socialeconomic-development-overall-of-kien-giang-provinceto-2020-part-1&catid=20:news&Itemid=287> VOV, (2012) ‘“Accessories Minister removed bridges” of Ben Tre Province’. Accessed 10 September 2012, <http://vovgiaothong.vn/nhung-cau-chuyen-kho-tin/2012/08/kien-tuong-xoa-cau-khi-cuatinh-ben-tre/> Wood Densities. (2012) Wood Densities . Accessed 15 September 2012 <http://www. engineeringtoolbox.com/wood-density-d_40.html.>
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Images References Figure 2.1: EWB. (2012). Kien Giang Province Map. Accessed 27 September 2012 <http://www.ewb. org.au/explore/initiatives/ewbchallenge/hfhewbchallenge/hfhmaps> Figure 2.2: EWB. (2012). Vietnamese Provinces Map. Accessed 27 September 2012 <http://www. ewb.org.au/explore/initiatives/ewbchallenge/hfhewbchallenge/hfhmaps> Figure 2.3, Top: Luong, Q. (2001) Bamboo Bridge near Phung Hiep, Can Tho. Accessed 27 September 2012 <http://www.terragalleria.com/pictures-subjects/footbridges/picture.footbridges.viet8135. html> Figure 2.3, Middle-left: TrailsofIndoChina (2010) Monkey Bridge. Accessed 28 September 2012 <http://www.tripadvisor.com/LocationPhotos-g293927-w2-Mekong_Delta.html> Figure 2.3, Middle-centre: Sarainen, I. (2012) Monkey bridge, Mekong Delta, Vietnam. Accessed 28 September 2012 <http://www.panoramio.com/photo/66023917> Figure 2.3, Middle-right: ImageVietnam. (2007) Monkey Bridge. Accessed 28 September 2012 <http://imagevietnam.vnanet.vn/ImageHandler//Upload/news/2007-9/13/0907to20l.jpg> Figure 4.2: Jassen, J. (2000) Designing and Building with Bamboo. International Network for Bamboo and Rattan, Netherlands. <http://www.inbar.int/publication/pdf/INBAR_Technical_Report_No20. pdf> Introduction Image: Phototropy. (2012). Bamboo Fence Friday. France. Accessed 6 October 2012 <http://www.flickr.com/photos/64318484@N04/7516237422/> Background Image: Hammond, A. (2007) Can Tho Floating Market, Mekong Delta, Vietnam Photography by Aidan Hammond. Accessed 7th October 2012 <http://hammond.aminus3.com/ image/2007-03-19.html> Implementation Image: Linghorn, L. (2007) Bamboo Chopstick Factory. United Kingdom. Accessed 6th of October 2012. <http://www.lexphoto.co.uk/albums/vietnam/slides/making%20bamboo%20 chopsticks.html> Practical Consideration Image: Cooper, J. (2011) Bamboo 1. Accessed 13th of October 2012. <http:// www.flickr.com/photos/jvcooper/5530074269/in/photostream> Ethics Image: Google Chrome. (2012) Bamboo Forest (2). Accessed 6th of October 2 0 1 2 . < h t t p s : / / c h ro m e . g o o g l e . c o m / w e b s t o re / d e t a i l / b a m b o o - f o re s t 2 1 4 4 0 x 9 0 0 / glibkfbimicknicndbdpjnphdefncmaj#category/home> References Image: Ambrazas, V. (2008) No name. Accessed 7 October 2012 <http://www.flickr.com/ photos/vitasamb2001/3328894611/sizes/o/in/photostream/>
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Appendix A: Risk Assessments C - Consequence
L - Likelihood
R - Risk
1 - First Aid Injury
A - Practically impossible
L - Low, monitor and manage
2 - Medical treatment injury
B - Not likely to occur
3 - Lost time injury less than 7 days
C - Could occur, incident has been heard of
M - Medium, monitor and maintain strict measures
4 - Lost time injury greater than 7 days, permanent total disability or fatality
D - Known to occur or has occurred before
H - High, review and introduce additional controls to lower the level of risk
E - Common or occurs frequently
5 - Multiple permanent total disability or fatalities
E - Extreme, do not proceed, immediately introduce further control measures to lower the risk. Re-assess before proceeding.
Table 12: Installation and usage of bridge risks
Job Steps
Hazards
Existing Controls
C L
Lash support poles onto existing bridge
Loss of components
Bridge making experience of villagers
-
Slipping
Grooves to improve 4 traction Preliminary investigation 5 to determine the structural integrity of the bridge Tensile strength 3 statistics and testing
Lash platform onto support poles Tie platform to handrail/s
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Bridge failure
Rope failure
Component Shrinkage
Low-shrinkage timber has been specifically chosen for the platform
3
Splinters
Chamfered edges
1
R
Further Recommended C L Controls D M Pre-connected - C components
R M
C E
Non slip surface finish
3
C
H
B H
Additional reinforcements 5 may be incorporated with the bridge add on.
A
H
C H
3
B
M
2
B
M
1
A
L
Increase safety factor Choose a stronger rope material (but expense increases) B M Ensure wood is fully seasoned or further seasoning of timber Natural waterproofers E
H
Gloves Sanded finish of bridge platforms
Table 13: OH & S for Prototype construction risks
Job Steps
Hazards
Existing Controls
C
L
Obtain bamboo and wood planks from Bunnings
Dying in a car accident
Seatbelts, air bags, road rules
5
A H
Injured by falling products
Well-constructed shelves and placement of products Responsible staff
4
A M Walk in the middle of the isle
3
A
M
2
B
2
A
L
Saw guards, goggles
3
B
B
M
Gas mask
3
B
M
Wear enclosed shoes
2
M Learn proper use 3 of equipment C H Dust extractors for 3 proper ventilation B M Wear steel capped boots 1
B
L
General intelligence
4
3
A
M
Machinery safety instructions
3
3
B
M
Everyone in using machinery should be certified Common sense
4
4
H M
1
A L
1
A
L
Take care
1
B
L
Take care, wear enclosed shoes Ensure good communication skills and practices between team Wear gloves
1
Pay attention to 1 A the task at hand C M Wear steel capped boots 1 B
L
1
B
M Organise a schedule with communicate any changes
1
B
L
1
E
H
1
D M
Cut bamboo and wood to size (300mm)
Shape wood planks (chisel grooves, drill holes)
Lash bamboo columns together
Lash land construction units
Stepping on nails Injure self with saw Inhale saw dust Drop plank on foot Drill through hand Injury though improper use of machinery Killed by bystander Cut off circulation by improper use of tie Hit on the head with bamboo Drop on foot Injuries from poor communication Splinters
R
Further Recommended C L Controls Use public transport 5 A or drive carefully
M Wear enclosed shoes
A M Do not be distracted by friends C H Ensure everyone knows the safety rules and machinery use A M Reinforce rules of sensibility Pay attention to the task at hand
L
Sand the wood Chamfer edges
R H
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Appendix B: Conceptual Sketches
Figure B1: Concept bridge design sketches
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Figure B2: Add-on concept sketches
93
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Appendix C: Add-On Concept Comparisons Table 14: Add-on concept comparisons
ADD-ON Concept sketches
Description Plank bolted onto the beam
Pros Simple design Adaptable Cheap
Lots of little nails on flat surface adhered to the beam
Adaptable Cheap
Tensioned cable holding plank on top
Cheap Adaptable Simple to implement
Plank bolted onto beam through another member
Can support a torque and force Adaptable
Triangular wood frame supporting the platform
Can support a torque and force Adaptable Uses local materials Can support a torque and force Adaptable
Plank attached to two arms that can be tightened around the bamboo pole, teeth on end for more friction Attaching an extra frame to the Y frame in order to fit two bamboo poles with platforms on top of them Existing bamboo pole notched and two square blocks placed in to provide a flat surface for the plank. Lashed together
Cons Bolting bamboo is problematic Cannot support weight Adhering is messy Cannot support weight Use of non-local materials Cannot support a torque Cable will come loose over time ( high maintenance) Relatively expensive Bolting is problematic Requires non â&#x20AC;&#x201C;local materials and practices Difficult to create triangular frame Non-local practices Expensive Complicated Non-local materials and practices
Can support a torque and force Very safe
Only for Y frames monkey bridges Non-adaptable Expensive Non-local practices
Can support a torque and force Adaptable Cheap Uses local materials and practices
Notching bamboo is problematic
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Platform lashed onto beam with the inclusion of an intermediate plank Plank bolted onto the beam with two supporting bamboo beams lashed onto it
Adaptable Cheap Uses local materials and practices Simple design Adaptable Cheap Can support a torque and force
Bamboo poles split and attached together to form a rail for the platform to sit on
Adaptable Cheap Can support a torque and force
Platform supported by two additional bamboo poles by lashing, Platform further supported by two ropes attached to handrails Platform of set on existing bamboo beam and supported by one other bamboo pole all lashed together. The torque that is created is balanced by the single rope to the handrail.
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May not be able to support a load or torque
Bolting bamboo is problematic Non-local practices and materials (bolts)
Notching or splitting the bamboo is difficult and reduced its strength Cheap Most monkey Can support a bridges only have torque and force one handrail and Less strain on thus it is not lashings due to adaptable inclusion of Creates a ropes narrower walkway Adaptable Cheap Can support a torque and force Less strain on lashings due to inclusion of ropes Uses local materials and practices
Slightly more expensive than other concepts but still cheap
Appendix D: More detailed research Bamboo Table 15: Material Comparisons
Tensile strength
Bamboo 35-300 N/mm2
Spruce 90 kp/mm2 = 9N/mm2
Concrete 1/10 of compressive strength
Steel 250-350 N/mm2
Compressive strength
64-110 N/mm2
43 kp/mm2 = 4.3 N/mm2
12.6 - 126 N/mm2
250-350 N/mm2
Shape characteristics
1.9 times stronger than a solid due to hollow cylindrical shape Efficient in compression and bending Acts as firebreak when growing, (61.2 untreated)
Strong as it is solid, more weight to obtain same loadbearing capacity
Best as composite with reinforcing in tension zone
Most efficient in tension, capable of most work in smallest cross section
(19.1)
Will not burn, but prone to spalling as steel expands
Loses elasticity, risk of quick failure
Minimal, unless imported
Transportation can be high
42 – 96,000 (ERG ’97)
91,618 (ERG ’97)
Regenerative capacity / year (Cooper ’92)3
80-300% (28,000 50,000 lb./acre)
3-6% (16,000 lb./acre - pine)
None
None
Time to maturity Subsequent maturity after initial harvest
7-9 years 1 year
60-80 years 60-80 years
-
-
Conforms to Natural Step’s 4 system conditions
Yes
Yes
No, fails first three
No, fails all four
Fire resistance (seconds until ignition, Dunkelberg ‘85) Embodied energy btu/cu.ft.
Melaleuca Timber Melaleuca is a highly adaptable native species that grows locally anywhere in Vietnam. It is highly beneficial for the environment as melaleuca forests play a critical role in the regulation of water levels and soil erosion, preserving large amounts of water in the wet season, and acting as a water source in the dry season (Trung, 2008). Hence it is a desirable building material as its production benefits the local community. Currently, melaleuca is used for
97
construction poles and its pulp is used for particle boards (Trung, 2008) using traditional methods and have a number of favourable characteristics for use in the platform construction.
Advantages • Very light timber (density 610kg/m3) (Trung, 2008) • Trees grow rapidly (basal diameter reaches 16 cm in the 11th year)(Trung, 2008) • Native species • Regulates water levels by absorbing large amounts of water in the wet season • High resistance to tangential static bending – 100.8 MPa
Disadvantages • High shrinkage rates (12.6% compared to 0.41% of the Acacia Auriculifomis a similar species) • Potentially cause lashings to loosen and will require a long aging/drying time Table 16: Comparison of different platform materials and their properties.
Species
Melaleuca Acacia Auriculiformis
Acacia Hybrid
Acacia Mangium
Volumetric shrinkage coefficient (%) Specific gravity (kg/m3) Maximum resistance to tangential static bending (MPa) Strength of longitudinal compression (Mpa)
12.6 610 100.8
0.41 560 99
0.39 538 99
0.46 586 97
46.5
45
41
42
Acacia Mangium Table 17: Examples of prices paid for acacia logs in Vietnam and used as soud timber for furniture.
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Date Apr 2003
Site Quang Tn
Price (US$/m3) 43
Hue Hue Hue
Product At farm gate about 30 em dbhob At m1ll gate• 15-20 em sed At mill gate: 20-30 em sed At mill gate: >30 em sed
Sep 2003 Sep 2003 Sep 2003 Sep 2003 Sep 2003 Sep 2003
Ho Chi Minh City My Xuyen (near Hue) Hue C1ly factories
AImill gate: 20 em sed At mill gate: >20 em sed At mill gate: >20 em sed
80 35-40 45-58
38 45 52
Appendix E: Project Proposal
Project Proposal 22 August 2012
Design Area Background: Transport Current Transport Ah Minh District is centred on the system of canals that have formed in the flood plains throughout the Mekong Delta. The canals are the main routes for transportation serving the same purpose as roads, with boats the main form of transport for both people and trading goods. However the high cost of diesel fuel makes boat transportation an unaffordable option for the majority of the locals. The canals are set out in a criss-cross pattern and the communes are spread along the banks of the river to maximize land available for agriculture. On land, there are also narrow roads for motorbikes and pushbikes that run along the canals and in between the rice paddies. Narrow bridges and ferries carry people and bikes from one side of the canals to the other. This current transport system is inefficient and suffers from congestion.
Current Projects The Kien Giang government has identified in the special issue of Kien Giang Union of Friendship Organisations (2011-2016) that transportation is an important issue in the Mekong Delta region. Initiatives developed to improve transportation include the construction of transportation routes in rural areas and concrete bridges to replace the footbridges. The footbridges are also known as â&#x20AC;&#x2DC;monkeyâ&#x20AC;&#x2122; bridges as they consist of a two pole construction, one used to balance on and the other to hold for support. While the government has prioritised the construction of concrete bridges to replace monkey bridges, this is not viable in more rural areas where smaller bridges are used for people crossing only. The monkey bridges further away from the main communities are made from local materials and must be regularly maintained by the residents. They are usually very basic, improvised and temporary as they struggle to withstand the harsh monsoonal season and floods.
Design Proposal We aim to design an appropriate transport system consisting of retractable bridges made of local materials to provide sustainable solutions for their construction and repair projects whilst using environmentally friendly building material.
WENRAY WANG | ISOBEL JAMES | MATHEESHA GUNARATNE | AMARA KRUAVAL | LASATH SIRIWARDENA
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Key Goals for the Project: ‐ ‐ ‐
‐
The design would be similar to the mechanics of the current monkey bridges to ensure that the residents of the area or the local mechanics can easily fix or replace parts of the bridge with minimal expenses. There will be a variety of sizes that can be appropriated to areas where motorcycles or bikes are in use as they would require larger and stronger bridges. They are retractable to withstand the monsoonal conditions and height adjustable remain above the water levels when the Mekong Delta floods (they must already be higher than the ferries that transport people and goods up and down canals to prevent further congestion). A modular construction will also be used so that the bridges can be built over both small and large sections of the river with ease.
Constitution
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‐
Our goal as Wimal is to produce innovative, sustainable and practical design solutions for problems that we face. Additionally the solution we produce must be cost effective and considerate of local customs and traditions.
‐
Wimal will commit to solutions that will meet and surpass the requirements of the problem at hand.
‐
Deadlines specified in the team Gannt Chart must be met.
‐
Communication between members will be efficient, thus social networking, the elearning site and telecommunications will be utilized to achieve this.
‐
Wimal is expected to meet at least once a week. The location will be either the Hearth located in the Wilkinson building or the Digital Hubs located in the Engineering Library.
‐
Wimal members will be committed to at least 6 hours of work a week.
‐
The penalty for late attendance, non-attendance or non-contribution without good reason or forewarning will result in a warning followed by a team meeting to discuss consequences.
‐
Wimal will maintain a minimal budget. Costs that are produced will be split evenly among team members. Any income supplied by the project will go back towards the project.
‐
Conflicts within Wimal will be resolved using democratic means in the form of team meetings.
WENRAY WANG | ISOBEL JAMES | MATHEESHA GUNARATNE | AMARA KRUAVAL | LASATH SIRIWARDENA
Figure E1: Gannt Chart
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Preliminary Report Preparation
Concept Model Construction
Presentation Preparation
Final Prototype Construction 23 days Sun 9/09/12 Tue 9/10/12
Well Deserved Break
Process Diary Checkpoint 1 0 days Thu 30/08/12 Thu 30/08/12
Process Diary Checkpoint 2 0 days Thu 6/09/12 Thu 6/09/12
Process Diary Checkpoint 3 0 days Thu 13/09/12 Thu 13/09/12
Group Presentation (10%)
Preliminary Report Submission (7.5%)
Design Finalisation
Draft Report Submission (7.5%)
Prototype Submission (10%) 0 days Tue 9/10/12 Tue 9/10/12
Final Report Submission (30%)
Participation / Reflection (10%)
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Project: EWB Project Progra Date: Wed 22/08/12
Design Concepts
4
Task
Milestone
0 days Thu 25/10/12 Thu 25/10/12
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Case Studies
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Page 1
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Aug '1220 Aug '1227 Aug '123 Sep '12 10 Sep '1217 Sep '1224 Sep '121 Oct '12 8 Oct '12 15 Oct '1222 Oct TFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFS
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Overview of Issue
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Appendix F: Calculations W1 = Weight Force of attached Bamboo
Density of Bamboo pole = 300 – 500 kg/m3 [wood densities]
Volume of Bamboo = π x 0.0352 x 0.300 m3 = 1.15 x 10-3 m3
Mass of Bamboo = 1.15 x 10-3 x 500 = 0.577 kg
Weight of Bamboo (W1) = 0.577 x 9.81
W1 = 5.66 N
W2 = Weight Force of Platform (Acacia Mangium wood)
Density of Acacia Mangium = 560-1000 kg/m 3 [Sein, C. Mitlöhner, R (2011)]
Volume of Platform = 0.250 x 0.300 x 0.03 m3 = 0.00225 m3
Mass of Platform = 0.00225 x 1000 = 2.25 kg
Weight of Platform (W2) = 2.25 x 9.81
W2 = 22.1 N
T = Tension in Bamboo rope
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T < 720 kp/cm3 (Rottke 2002)
T < 7060 N/cm3
Diameter of rope = 3cm
Length of Rope = 250cm
Volume of Rope = π x 1.52 x 250 cm3
= 1770 cm3
T < 1770 x 7060 N
T < 1.25 x 104 kN
F = Weight Force of live loading
Max. mass of person and goods on a platform = 100kg
F = 100 x 9.81
F = 981 N
Ox and Oy = Reactions at O
T
O(y)
F 20
50
60
50
FORCE EQUILIBRIUM CALCULATIONS: ∑F x = 0, ∑Fy = 0, M0 = 0 ∑F x = 0:
θ=75°
Tcos75 = Ox
∑Fy = 0:
Tsin75 – W1 – W2 – F + Oy = 0
Mo = 0
W2 x 0.05 + W1 x 0.11 + F x 0.16 – Tsin75 x 0.18 = 0
T = 913 N
W1
W2
Figure F1: Free body diagram of the platform addition.
Ox = 3530 N Oy = 128 N CONCLUSIONS: Since the tension is shared over two ropes the tension in each rope will be half thus, T = 457 N. The maximum tensile stress of the rope is well above the calculated value thus the rope failing due to excess load is very unlikely.
103
Appendix G: Construction Manual
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105
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Appendix G1: A5 Construction Manual
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