concrete VOLUME 56 ISSUE 3/4
readinG concrete can contribute to your skills maintenance
The Capital Rocks DUNNING THORNTON HELP EARTHQUAKE STRENGTHEN WELLINGTON
Portrait of a House A PHOTOGRAPHIC ESSAY OF IAN ATHFIELD’S HILL SIDE RESIDENCE
A Concrete Geyser 6-GREEN STARS FOR AUCKLAND’S MOST SUSTAINABLE BUILDING
THE MAGAZINE OF THE CEMENT AND CONCRETE ASSOCIATION OF NEW ZEALAND
UPFRONT
concrete
For the first time in a long time Wellington recently felt the effects of an earthquake.
Editor/Advertising:
Although insignificant compared to the forces that ravaged Christchurch and the Canterbury region in 2010 and 11, the tremor on Sunday 21 July in particular has shaken residents of the Capital into realising they are in no way immune from earthquakes.
MAGAZINE Adam Leach +64 4 915 0383
adam@ccanz.org.nz Subscriptions:
With only minor structural damage to a handful of buildings, the series of quakes situated close to Seddon has nonetheless acted as a reminder of Wellington’s vulnerability, and resulted in a flurry of building assessments and scheduled strengthening work.
Kylie Henderson
That is not to say however, that Wellington has been entirely complacent following the Canterbury quakes, a fact clearly evident by the entries in the 2013 Earthquake Strengthening Awards.
by CCANZ (Cement & Concrete
As highlighted on pages 16-18 the work of Wellington based civil and structural engineering practice Dunning Thornton featured prominently in the Awards organised by the New Zealand Society of Earthquake Engineering (NZSEE) and supported by the Wellington City Council.
PO Box 448
Congratulations to Dunning Thornton and the other winners, and in particular the organisations responsible for the Awards for recognising an area of construction that will become of increasing importance over the next decade or so. You may be aware that Holcim (New Zealand) Limited announced in early August that it will spend more than NZ$100 million over the next three years constructing an import terminal and related infrastructure that will allow it to import and distribute bulk cement for supply to the New Zealand market. Holcim New Zealand hopes to make a decision over the next few months on the location of the terminal, which once operational will see local production of cement at their Westport cement plant cease and the plant close. Along with Golden Bay Cement’s world-class domestic facility, the Holcim New Zealand initiative will see cement (and concrete) continue to provide a range of sustainable solutions for New Zealand’s built environment. Another significant milestone on the horizon for our industry is the 50th anniversary of the New Zealand Concrete Society (NZCS) in 2014. Established in 1964, the NZSC is a learned Society with a focus on technical excellence, and is not influenced by external commercial interests. Over its five decades in existence, the NZCS has sought to encourage a greater knowledge and understanding of all aspects of structural and architectural concrete and to support their development and use where appropriate. A range of communication activities and events are planned for 2014, which will celebrate the Society’s achievements, its notable (larger than life) members, as well as a number of the enduring concrete structures that grace the New Zealand landscape. Celebrations will culminate with the 2014 New Zealand Concrete Conference to be held in the Society’s spiritual home of Wairakei.
+64 4 499 8820 admin@ccanz.org.nz concrete is published quarterly Association of New Zealand)
Level 6, 142 Featherston St Wellington NEW ZEALAND Tel: +64 4 499 8820 Fax: +64 4 499 7760. Email: admin@ccanz.org.nz Website: www.ccanz.org.nz ISSN: 1174-8540 ISSN: 1179-9374 (online) Disclaimer: The views expressed in concrete are not necessarily those of the Cement & Concrete Association of New Zealand. While the information contained in the magazine is printed in good faith, its contents are not intended to replace the services of professional consultants on particular projects. The Association accepts no legal responsibility of any kind for the correctness of the contents of this magazine, including advertisements. © Copyright 2013 CCANZ (Cement & Concrete Association of New Zealand)
We must not forget however, the small matter of this year’s conference, scheduled for 3-5 October at the Millennium Hotel in Queenstown. The technical programme promises to be rewarding, while the range of social activities will be enhanced by the magnificent scenery provided by The Remarkables. I look forward to seeing as many of you as possible in Queenstown. Rob Gaimster CCANZ, CEO
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Cover photo: The Royal Society, Wellington.
NEWS
NEWS YOUR NEW BEST FRIEND – GUIDES FOR BUILDERS WORKING IN CANTERBURY Builders in Canterbury are facing a different set of challenges when repairing and rebuilding houses damaged by earthquakes, and now they have a new best friend - two new booklets produced by MBIE - Below-Floor Work and Above-Floor Work.
Both provide references to relevant sections in the more detailed MBIE technical guidance. Visit the MBIE website to download these leaflets www.dbh.govt.nz/canterbury-earthquake-residentialbuilding
Both booklets outline the regulatory requirements for builders, and highlight special issues for working in the Canterbury green zone.
TH E GU IDE FOR CA NT ER BU RY BU IL DE RS
ABOVE-FLOO R WORK
These booklets are an introduction to the more detailed technical guidance published by MBIE: Repairing and Rebuilding Houses Affected By the Canterbury Earthquakes. Below-Floor Work is an introduction to MBIE’s guidance for repairing or replacing foundations. It includes diagrams to help builders assess foundation damage and check ground height requirements as well as checklists of what to consider when repairing foundations or lifting and re-levelling floors. The booklet Above-Floor Work focuses on structural repair work which includes repairs to wall and roof framing and bracing, repairs to cladding, chimney and fireplace repairs, and repairs to retaining walls.
[ Your new
best friend]
THE GUI DE FOR CAN TER BURY BUI LDE RS
BELOW-FLOOR WORK [Your new best friend]
The booklets also briefly cover the building code, building consents and builders’ legal responsibilities which include ensuring that the building work complies with the building consent, complies with the agreed contract, and where the building work is not covered by a building consent, complies with the building code.
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NEWS
NEW WEBSITE FOR LBPs The launch of a new website will make it easier for Licensed Building Practitioners (LBPs) to access information online. The website also provides information for New Zealanders wanting to find the right people for building and renovation work, and will act as a one-stop shop and provide crucial information for those in the industry and the public.
ROC
KCOTE
The LBP scheme was established in late 2007 to improve and formally recognise the skills and competence of building practitioners. LBPs are designers, carpenters, bricklayers, roofers, external plasterers, site and foundations specialists, who have been assessed as competent to carry out work essential to a residential building’s structure or weathertightness. There are currently 23 000 LBPs in New Zealand accountable to the Building Practitioners Board. Visit www.business.govt.nz/lbp
Proven technology. REVISED STANDARD PUBLISHED FOR CONCRETE MASONRY BUILDINGS NZS 4229:2013 Concrete Masonry Buildings Not Requiring Specific Engineering Design sets a minimum standard for the design and construction of reinforced concrete masonry buildings. The Standard has undergone a revision to ensure it is consistent with the loadings values and requirements given under the AS/NZS 1170 loadings Standards. The Department of Building and Housing (now part of the Ministry of Building, Employment and Innovation (MBIE)) and Standards New Zealand sponsored the revision of NZS 4229, with additional funding provided by EQC. The key changes to the Standard are as follows. • The earthquake zones have been aligned with NZS 3604:2011 Timber-Framed Buildings, introducing four zones instead of three.
Lightweight AAC masonry flooring systems are a tried and tested method of construction around the world. The Integra Flooring System offers a durable and cost effective solution in both light commerical and residential flooring with many benefits associated with masonry floors; Energy efficiency, thermal mass, sound absorbing qualities and speed of installation to create a solid, lightweight masonry floor. Integra - lightweight concrete systems for all your building projects.
• Earthquake actions may now be calculated specifically for a site’s subsoil classification. • Previously, NZS 4229:1999 covered masonry veneer wall covering. This information is to be contained in Acceptable Solution E2/AS3 in NZBC Compliance Document E2 ‘External Moisture’. Until the current revision of E2/AS3 is complete guidance is provided in Appendix E of NZS 4229:2013. NZS 4229:2013 supersedes NZS 4229:1999 and can be purchased from the Standards New Zealand website www.standards.co.nz
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www.reseneconstruction.co.nz 0800 50 70 40
CCANZ APARTMENT
DESIGN GUIDE CCANZ has developed the Apartment Design Guide: Guidelines for the
Design of Multi-Storey Apartment Buildings in New Zealand. This guide is for planners, architects, investors and everyone with an interest in good quality apartment design. “Apartment living is becoming increasingly common in New Zealand, especially in the more densely populated cities of Auckland, Wellington and Christchurch,” says CCANZ Architect (EU) Ralf Kessel. “While reasons for this include increased immigration and land constraints, the fact is that New Zealanders’ lifestyles are also changing.” “There are more households comprising couples and singles, more people renting because they can’t afford to buy, and more city dwellers moving in from the suburbs because they enjoy the proximity to work, shops and nightlife.” “There are also increasing numbers of retirees who want the convenience of apartment living and who require less space after their children have left home,” adds Ralf. “However, as a country we are still relatively inexperienced when it comes to apartment design, and copying international practice isn’t always the answer: what works for someone in New York or Berlin won’t necessarily keep a Kiwi happy.” “We value our connection to the outdoors, we like to drive, and we have more bulky possessions needing storage such as tools
and sporting gear,” says Ralf. “As well as providing extra room, New Zealand designers have the added challenge of tackling earthquake protection within the structural design.” “With this guide we set out some key considerations for designing New Zealand apartment buildings, their amenities and shared spaces. It also includes some tips on recommended minimum sizes, daylight and interior climate requirements, effective soundproofing and fire protection.” “We also look at how to design a sustainable and durable building that enhances rather than detracts from the urban landscape, as well as providing some links to interesting and innovative apartment complexes,” concludes Ralf. To download a free copy of the Guide visit the CCANZ website www.ccanz.org.nz
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CCANZ is delighted to announce that the 2013 Concrete3 Sustainability Awards ARE now open for entries. The AwardS provide architects, designers, engineers and/or industry with the opportunity to submit a concrete based product, project or initiative, substantially completed within the past three years, that demonstrates sustainability in either the production or use of concrete.
Previous winners have included The Pride, Lion Nathan’s integrated manufacturing and warehousing facility in East Tamaki, which made extensive use of recycled glass as aggregate in concrete, and the Northern Gateway Toll Road, of which every aspect, from design through to operation, considered ways in which to contribute to New Zealand’s sustainable development.
How will entries be judged?
In 2010 the Fletcher Construction Company took home the Award for the Tauranga Harbour Link’s “Mix M”, while in 2011 Peddle Thorp Architects’ conversion of 21 Queen Street into a modern and vibrant office/retail complex received the highest honour.
Award categories
• Excellence in Commercial Concrete Construction • Excellence in Civil Concrete Construction • Excellence in Concrete Innovation • Excellence in Concrete for the Community
Sustainability embraces environmental, economic and social considerations. Each concrete based product, project or initiative entered may relate to any of the following areas:
• Managing natural resources • Minimising energy use • Protecting against pollution • Respect for people • Setting performance targets
The 2013 Concrete3 Sustainability Supreme Award winner will be selected from the following categories: • Excellence in Residential Concrete Construction
Last year Athfield Architects collected the top prize for its extensive refurbishment of the new Christchurch Civic Building on Hereford Street - a transformation of what was the New Zealand Post Building into an architectural statement that adds tremendous value to Christchurch.
• Lean production less waste
Within each Award category entries will be judged by a panel of New Zealand and international industry experts, using an environmental, economic and social sustainability set of criteria. Extra credit will be given to unique factors and entries that cover more than one facet of sustainability (e.g. both environmental and social sustainability).
How to enter & closing date For entry information and an entry form visit www.sustainableconcrete.org.nz. You have until Friday 30 August 2013 to submit your entry.
Announcement of results The winners will be announced at a presentation at the New Zealand Concrete Conference, October 2013. The December 2013 issue of Concrete magazine will include a detailed report on the award, based on the material submitted by the entrants. The winner of the Concrete3 Sustainability Supreme Award will be presented with the 2013 Concrete3 Sustainability Award trophy.
SPONSORED BY
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ATHFIELD ARCHITECTS CIVIC BUILDING, CHRISTCHURCH 2012 SUPREME AWARD WINNER
EntER now www.sustainableconcrete.org.nz
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CONCRETE CONTRIBUTES TO GEYSER BUILDING’S 6-GREEN STARS AFTER A THREE YEAR JOURNEY, GEYSER BUILDING HAS RECEIVED OFFICIAL NOTIFICATION FROM THE NEW ZEALAND GREEN BUILDING COUNCIL THAT THE PROJECT HAS A 6-GREEN STAR NZ OFFICE BUILT V1 CERTIFIED RATING. The design for Geyser, created by Pattersons Architects, received New Zealand’s first 6-Green Star design rating in 2009. The new Built Rating confirms that the building achieved what the design promised. ‘GREEN’ FEATURES Geyser is a commercial community of five individual four storey buildings in Auckland’s Parnell set around an arrangement of open walkways, elevators and stairwells. A five storey basement also accommodates 165 vehicles which are serviced by an automated car stacker machine. Geyser uses state-of-the-art eco-technology to enable the building to heat itself by trapping warm air between its walls in the winter, while in summer the entire outer skin opens electronically for full 8 concrete
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ventilation. 25 percent of the car parking spaces in the automated car park stacking system are for small cars and the building recycled 70 percent of its waste during the construction process. Geyser also has its own rainwater harvesting system to store and supply water to low flush toilets and irrigation systems, and low flow sanitary fixtures are used throughout. The building aims to use 27% less energy and half the amount of artificial lighting and water. CONCRETE MIX In addition to its headline features the selection of concrete mix, construction methodology and placement approach were all undertaken with regard to sustainability. For example, 2500 tons of recycled concrete aggregate were used for the project and 550
tons of cement were replaced with recycled binder. A Green Star shotcrete mix was developed specifically for the project. Main contractor Mainzeal, concrete supplier Holcim (New Zealand) Ltd and subcontractor Shotcrete Services worked together to develop the perfect shotcrete recipe. Thanks to the enthusiastic input of all parties the market now has a new and proven Green Star shotcrete product. CONSTRUCTION METHODOLOGY Geyser was designed and constructed as a ‘top down’ project, where basement excavations are undertaken simultaneously with the above ground construction works. The underground structure was originally designed to be excavated floor by floor. The construction team was required to pour each respective floor level prior to undercutting/excavating to the floor level below. This method requires workers to operate heavy machinery in confined spaces so careful consideration was given to reducing the health, safety and environmental impacts.
It is hoped this approach will change the method and the mind set for future top down construction projects. GEYSER PLAUDITS General Manager of Samson Corporation Marco Creemers says being awarded the Built Rating is the result of a tremendous effort to be true to the designs Pattersons Architects came up with in collaboration with Samson. “At the start of this process we had a vision, to build a truly sustainable building that would stand the test of time and have a minimal impact on the environment,” says Mr Creemers. “The 6-Green Star Built Rating is an affirmation that we really did achieve what we set out to with the Geyser building.” The CEO of the New Zealand Green Building Council Alex Cutler said the 6-Green Star NZ Office Built V1 Certified Rating represents “world leadership” in building green buildings. “Coming up with a green building design is only the first step in what is a very challenging task – to actually build a green building,” says Ms Cutler. “After awarding the Geyser building New Zealand’s first 6-Green Star Design Rating, we are absolutely thrilled to be able to award Geyser a 6-Green Star Built Rating.”
A system that achieved progressive and structured bulk excavation was identified as an improvement over the usual floor by floor excavation. The resultant method of construction involved the utilisation of 56 no. 1200mm diameter piles (rather than the designed 86 no. 450mm diameter piles with permanent steel struts) – these could self-support, removing the need for floorby-floor excavation. In addition, micro silica was removed from the shotcrete concrete and replaced with inert fly ash helping to reduce health implications for workers, while catalytic convertors were fitted on all excavators to improve air quality and reduce pollution. Taking this proactive, rather than reactive approach meant hazards and related OHS risks were able to be eliminated and/or reduced during the design and planning stage of the underground construction works by using a desired ‘Safety in Design’ approach.
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CCANZ structural engineer Alistair Russell takes a quick look at some issues that can arise with new concrete driveways.
WHAT CAN I EXPECT FROM MY NEW CONCRETE DRIVEWAY? Constructing a residential concrete driveway on the ground is relatively straightforward, however there are many aspects of design and construction that require skill and experience in order to produce an acceptable finished product.
be viewed from a distance of 3 metres. View the driveway from this distance when assessing the driveway’s surface finish. COLOUR DIFFERENCES Concrete generally lightens in colour as it gains strength and dries out. Contrasting dark and light areas of new concrete will become less visible as the concrete dries out. A particularly severe type of discolouration that may appear as the concrete dries out is ‘pinto’. The possible causes of pinto are many and varied, ranging from hard-troweling that densifies and darkens the surface through to moisture transfer from adjacent soil.
Concrete uses naturally occurring, and hence variable, ingredients – sand, aggregate, water and cement. Some variation in colour and texture of a concrete surface is to be expected. But just what is “acceptable” in a new residential concrete driveway? WHEN TO INSPECT A concrete pavement takes 3 – 6 months to harden and dry out, so judging it a week or so after casting may ignore some of the longer term changes. In time the concrete will gain strength and lighten in colour, but it will continue to shrink for up to 6 months.
Letting the concrete weather may reduce the contrast in colour but does not always produce satisfactory results. Various proprietary applications are also available to mitigate the appearance of pinto. EXPOSED AGGREGATE Constructing an exposed aggregate driveway requires a degree of expertise. A specialist concrete placer should be chosen on the basis of other driveways they have completed successfully.
SURFACE FINISH
The surface finish on a concrete driveway needs to provide skid resistance. A smooth surface will be treacherous to walk on in wet or frosty weather, particularly if it is on a slope. A light broom finish is therefore commonly applied. Sample panels can be used to agree on the surface appearance. The NZ standard for concrete finishes requires sample panels to 10 concrete
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Variation in the distribution and size of stone is to be expected, the surface should be viewed for uniformity from a distance of 3 metres. A surface sealer is usually applied to enhance the exposed aggregate by giving it a ‘wet look’. It must be remembered that removing the top layer of paste to expose the aggregate may also expose surface defects. These may include air voids, which can occur if the concrete is not vibrated.
STRENGTH Concrete takes approximately one month to achieve maximum strength; it will take longer in cold weather. As such, the hardness or strength of the concrete driveway cannot be judged in the first few weeks after construction. SURFACE CRACKS While the visual acceptability of cracks is very subjective, a 0.3mm wide crack can be regarded as acceptable. Surface cracks up to 0.3 mm wide can be expected in concrete for a variety of reasons and such small cracks do not compromise the strength of the concrete and cannot be seen unless viewed up close. Cracks wider than 1mm should be assessed on an individual basis in terms of possible effects on durability and performance requirements and, depending on the surface texture and finish, also on aesthetic requirements.
TOLERANCES Like all building materials, some tolerances on dimensions and flatness should be allowed for in concrete driveways. For instance, a 100mm thick driveway can be between 95mm and 105mm thick.
DRIVEWAY CROSS-FALL Despite adopting good design, detailing and construction practices to minimise the risk of cracking, there will be situations where cracks may occur as a result of movements in concrete due to changes in its moisture content and temperature. Driveways may also be subjected to excessive loads that may also result in cracking. It is important to keep vehicles off a new concrete driveway for 2 – 3 weeks. If cracking does occur over time, it is important to identify the cause, and then assess whether the cracking is acceptable, or needs repair.
A 1 in 50 cross-fall should be built into a driveway to prevent rainfall puddling on the surface. However, some minor puddling up to 5mm deep is to be expected when allowing for tolerances. CCANZ MATERIAL CCANZ Residential Concrete Driveways and Paths (IB 80) provides further guidance on the planning, design, construction, maintenance and specification aspects that need to be considered to ensure a successful concrete paving project. A leaflet based on this article, along with IB 80, is free to download from the Publications section of the CCANZ website www.ccanz.org.nz
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A VILLAGE ON THE HILL Supported by CCANZ, Portrait of a House is a book by photographer Simon Devitt in collaboration with graphic designer Arch MacDonnell (Inhouse Design) that explores Athfield House, an architectural experiment that Ian Athfield started in 1965 on the Khandallah hillside in Wellington.
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All images © Simon Devitt, except *© AAL.
Still being altered and extended today, the house is renowned in bohemian and academic circles for its many colourful dinner parties, and is infamous with neighbours
*
past and present for the antics of its free-range livestock and frequent run-ins with Council. At last count 25 people live in its array of buildings, with 40 people working for Athfield Architects within its walls. Ironically the property was given a heritage listing by Council a number of years back, despite the years of acrimony, to which Ath laughed “what a bloody cheek!” and had the status changed to ‘organic heritage’ so that he could continue working on it. So the maverick architect has created an important piece of New Zealand history. About his almost 50-year experiment he understatedly concludes, “It hasn’t been entirely successful but it hasn’t been a failure.” This is an extraordinary story told though Devitt’s sensitive eye, blended with historic photographs, paintings and drawings from the Athfield archive. Clare Athfield’s contribution of her own recipes (dating from the 1960s until now) complements a selection of personal letters by family, friends, colleagues and clients which are insightful and often very funny - memories that make Simon’s photographs all the more potent in their beauty and silence. The sense that ‘the walls can talk’ is evoked in Devitt’s narrative, and is a record of why the house is an important part of Wellington’s history, with many of its stories now urban legend. However, the photographer doesn’t set the house up in a heroic way, although there are undoubtedly some sublime images. He is candid, ambiguous, and at times irreverent - but then so are the owners. The idea for the book came from Devitt’s admiration of Robin Morrison’s work. “A house is a pretty refined subject to make a book about,” explains Devitt. “It is not market driven, it is content driven and born out of passion. Life has happened there like in no other house, and the ‘living’ leaves its evidence, time has played out on its surface. The Athfield house is an accessible counterpoint to a largely asset based living that pervades New Zealand.” Portrait of a House was launched in May 2013, with events in Wellington, Auckland and Christchurch. Only 1,000 copies will be printed. At 140 pages, uncoated paper, an exposed, section sewn binding and cardboard case, this will be a true collector’s item for those interested in New Zealand history, architecture, design and photography. To purchase a copy of Portrait of a House contact Balasoglov Books 021 662 339.
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CCANZ has 10 copies, signed by Ian Athfield and Simon Devitt, to give away to lucky readers of Concrete magazine. To go in the draw answer the following simple question: What heritage listing status does the Athfield house have with the Wellington City Council? Email your answers to library@ccanz.org.nz. Entries close 30 September 2013.
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Client The Royal Society of New Zealand Architects Studio Pacific Architecture (Stephen McDougall & Simon Hardy) Project Managers Ian Mills Structural Engineer Dunning Thornton Consultants (Alistair Cattanach)
Images. Patrick Reynolds.
Contractor Fletcher Construction
CAPITAL EARTHQUAKE STRENGTHENING ONE OF NEW ZEALAND’S MOST RESPECTED CONSULTANTS, WELLINGTON BASED STRUCTURAL AND CIVIL ENGINEERING PRACTICE DUNNING THORNTON FEATURED PROMINENTLY AMONG THOSE RECOGNISED AT THE 2013 EARTHQUAKE STRENGTHENING AWARDS. 2013 Earthquake Strengthening Awards Organised by the New Zealand Society for Earthquake Engineering (NZSEE), with the support of Wellington City Council, the Earthquake Strengthening Awards showcased examples of seismic upgrade projects, to promote a positive and inspirational message to building owners and the public.
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The awards were judged by a panel of structural engineers and architects, and were assessed according to both engineering and architectural standards. A total of 31 high quality entries were received from across the country, all of which were displayed publicly at the recent Wellington City Council ‘Wellington Rocks’ Earthquake Building Safety Expo and the NZSEE conference. Dunning Thornton, along with Studio Pacific Architecture, took home the top honour as well as the Best Engineering Solution Award, for the redevelopment of the Royal Society of New Zealand’s building in Wellington, a project that posed many concrete related challenges.
2013 Earthquake Strengthening Awards Overall Winner & Best Engineering Solution
Best Adaptive Re-use
The Royal Society of New Zealand, Wellington
Regent Cinema Complex, Wellington
• Architect: Studio Pacific Architecture • Engineer: Dunning Thornton
• Architect: Archaus • Engineer: Spencer Holmes
Best Project Under $1m
Heritage Award
The Mayfair, New Plymouth
Chevening Apartments, Wellington
• Architect: Bonnifait + Giesen • Engineer: Tse Taranaki
• Architect: Studio Pacific Architecture • Engineer: Beca
Highly Commended – Residential
Highly Commended – Commercial
Central Park Apartments, Wellington
Data Crate – Victoria University, Wellington
• Architect: Novak+Middleton • Engineer: Dunning Thornton
• Architect: Tennent + Brown Architects • Engineer: Dunning Thornton Judges Commendation – Industrial Carter Holt Harvey No2 Recovery Boiler, Kawerau
• Engineer: Beca Dunning Thornton Consultants
involved over recent years demonstrates experience in all types of
Dunning Thornton are a medium sized Wellington based practice providing structural and associated civil engineering consultancy services locally, within the region and nationally. They have a reputation for innovative, buildable designs and a practical, cando approach to problem solving.
structural engineering, from designing at a small residential scale
The broad range of projects with which the practice has been
buildings for seismic strengthening.
through to multi-storey buildings, theatres and bridges. As represented by their entries in the 2013 Earthquake Strengthening Awards an increasingly large component of the practice’s work programme revolves around retrofitting existing
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This is an area of work that will no doubt see further growth following the July earthquakes in the nation’s capital, which have made many Wellingtonians apprehensive to re-enter their office buildings. Royal Society of new zealand Building By Alistair Cattanach and Chris Speed The Royal Society had outgrown their original 1960’s Warren and Mahoney classic style reinforced concrete-and-concrete block headquarters, and required modern, larger premises with more flexible floor plates and better conference/seminar space. The project however, needed to be economically driven in an uncertain funding environment. The new building is a celebration of the “campus” feel of the organisation, and demonstrates multiple structural technologies. The original building’s structure is re-used economically, and by re-working the seismic system and foundations an additional floor was added. A new wing with long span double tee floors provides flexible conference and meeting spaces. The structural elements are very much on display, and required careful consideration and coordination of the components to achieve the architectural intent. Longitudinally the existing building has been strengthened by “selective weakening” - saw cutting the deep spandrels and the wall bases to reduce the shear demand on the original concrete masonry and allow the insertion of new energy absorbing elements. This regularises the original blockwork into a limited ductile wall-frame that is able to resist the additional mass added above. Small confining rubber pads were added in the wall saw cuts so that the building had additional robustness if it were subject to a larger than design or near-fault earthquake. Transversely the building had all of the internal walls removed and now relies on a new concrete PREcast Seismic Structural System
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(PRESSS) wall at the rear, integrated in with the original architectural rhythm of the block panels. The front of the building is braced outside the floor plate by the new annex, which reduced the cost and disruption of trying to insert a large new seismic bracing element into an existing building. Connections crossing the atria bridges are detailed to have some limited yielding if ever overloaded beyond their dynamic capacity. In addition, the small remaining blockwork panel to the front facade has been vertically pre-stressed to provide additional secondary redundancy and robustness. The new annex employs cantilever PRESSS concrete walls in both directions. These walls incorporate damage control techniques both in their PRESSS self-centring nature but also in their careful connection to the floors. Articulated connections allow for wall movement without inducing large movements or yielding in the floor diaphragms. Some of the walls and their associated hardware are expressed in the main entry foyer/atrium space, and the client is very proud to explain their technology to visitors to the building. The existing blockwork walls are externally insulated, and with the existing floors now exposed to help moderate internal temperatures and allow for a naturally ventilated building with a minimum of automated services. Exposed concrete in the new conference space also aids thermal control though its “flywheel” effect in a space with a highly varying population. The project demonstrates the flexibility offered by concrete and concrete masonry, particularly in terms of the capacity for re-use, its key role in passive solar design, and damage control technologies that express the science and innovative nature of the client throughout the structure. The next issue of Concrete magazine will feature two other recently completed Wellington earthquake strengthening projects in which Dunning Thornton took the structural lead.
Simon DeVitt Photography
“The Holcim Awards is an amazing opportunity to contribute ideas, but also to learn from others and to celebrate those that win.” Maria Atkinson AM, Co-Founder Green Building Council of Australia. Member of the Global Holcim Awards jury 2012.
4th International Holcim Awards for sustainable construction projects. Prize money totals USD 2 million.
Renowned technical universities lead the independent juries in five regions of the world. They evaluate projects at an advanced stage of design against the “target issues” for sustainable construction and allocate additional prizes for visionary ideas of young professionals and students. Find out more about the competitions at www.holcimawards.org The Holcim Awards is an initiative of the Swiss based Holcim Foundation for Sustainable Construction. It is supported by Holcim and its Group companies and affiliates in around 70 countries, including Holcim New Zealand. Holcim Ltd is one of the world’s leading suppliers of cement and aggregates.
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BBR CONTECH - CELEBRATING 50 YEARS OF PERFORMANCE A LEADER IN NEW ZEALAND’S CIVIL, BUILDING AND REMEDIAL ENGINEERING INDUSTRY IS CELEBRATING FIVE DECADES OF SERVICE – AND AN ENVIABLE RECORD OF PERFORMANCE IN SOME OF THE COUNTRY’S MOST SIGNIFICANT CONSTRUCTION AND REMEDIATION PROJECTS. Established in 1963, BBR Contech has earned an outstanding reputation for its technical expertise in the fields of posttensioning, ground anchoring, seismic strengthening, construction engineering and structural maintenance, repair and retrofitting. “We’re proud to have worked on some of New Zealand’s most well-known historic and modern landmarks,” says Managing Director Paul Wymer. “We’ve also been part of some very substantial infrastructure projects, and today we’re deeply involved in the post-earthquake Christchurch rebuild programme.” THE EARLY DAYS BBR Contech’s story began in the 1950s, when the Government called for tenders for the Roxburgh Dam. That contract was won by an international joint venture that included Conrad Zschokke, a contractor from Switzerland. Once the project was complete, Zschokke established a local presence, joining a Masterton company to form Rigg Zschokke. When in the early 1960s projects started requiring post-tensioning technology, Zschokke’s Swiss-based business associate BBR was in the perfect position to help – and the rest, as they say, is history. BBR New Zealand was established in 1963. In the half-century since then, a series of mergers and acquisitions has seen the company change names, market new skills and techniques and undertake a diverse range of projects in New Zealand and overseas. Today it’s known as BBR Contech, with headquarters in Auckland, offices in Wellington and Christchurch, and a dedicated team of some 70 specialists working with clients nationwide. 20 concrete
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Innovation and Excellence BBR Contech has long been committed to innovation, quality and service excellence. It’s now widely recognised for its proactive approach, both in project design and delivery and in the development and implementation of new products, processes and technology. “We believe in working closely with our clients to develop smart, tailored solutions that meet their specifications and deliver longterm certainty of performance,” says Wymer. “It’s about assuring them of international best practice in everything we do.” The company is kept constantly up to date on new developments through its membership of the globally influential BBR Network. “We’re fortunate to have the resources and the agility to respond quickly to market demands and new opportunities,” says Wymer. “It’s enabled us to be at the forefront of many key projects in New Zealand and the Pacific.” AWARD-WINNING PERFORMANCE You name it, BBR Contech has probably worked on it. Highlights in the past 50 years have included Auckland’s Sky Tower, the West Coast’s Otira Viaduct, Wellington’s Ngauranga flyover, Manukau City’s Ormiston Road stay cable bridge, and 1.5 million square metres of post-tensioned slabs on some 250 projects. The company’s now involved in a number of structural upgrade and new projects, such as those using innovative damage resistant design systems. Industry recognition highlights for BBR Contech have included the 2007 Supreme New Zealand Engineering Excellence Award for its work on strengthening the foundations of the nation’s electricity transmission pylons, and the 2009 New Zealand Concrete
CONCRETE
FUTURES Society’s Concrete and Technology Awards for its contribution to Wellington’s Alan MacDiarmid Building.
DAMAGE RESISTANT DESIGN USING CONCRETE SYSTEMS
EXPERIENCE AND DEPTH OF EXPERTISE BBR Contech’s survival in the competitive New Zealand market is of course a reflection of the specialist knowledge, expertise and experience of the people who work there. The retention of these skill-sets is key to BBR Contech’s position as a market leader and premium supplier in the engineering industry. “We offer our clients well researched, thoroughly tested and proven solutions at every stage and level of a project,” says Wymer. “What’s more, we back this up by meeting the highest standards of quality assurance, environmental management and health and safety performance.” ACTIVE INDUSTRY PARTICIPATION BBR Contech’s philosophy of proactive engagement is evident in its involvement with the wider engineering industry – a commitment that’s been a hallmark of the company since its beginnings. Rob Irwin, the company’s founder, instilled the philosophy in all staff and encouraged active industry participation and strong support of university engineering faculties. Sadly, Irwin passed away in 2010, but the team continues to uphold his philosophies and practices in its day-to-day work. BBR Contech’s long standing involvement with the New Zealand Concrete Society has been the foundation for its active participation in developing technology related to the concrete construction industry. Company employees have also held representative positions on the Cement & Concrete Association of New Zealand’s Board. Senior employees hold memberships with the Structural Engineering Society and New Zealand Society for Earthquake Engineering. Today, BBR Contech is also a key partner in research projects with New Zealand universities, and provides guest lecturers for seminars and other events. “It’s about sharing our specialist knowledge, learning from others and working together for the future of the industry,” says Wymer. “This is a pretty amazing business with which to be involved – and it will continue to be for many years to come.”
Advances in structural design and earthquake engineering, such as PRESSS, base isolation and slotted beams, are being developed for a safer and more secure New Zealand.
To request your free copy of the Concrete Futures DVD email admin@ccanz.org.nz
www.ccanz.org.nz
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CCANZ Library Listed below is a small selection of recently acquired material by the CCANZ library. email library@ccanz.org.nz TO BORROW. EARTHQUAKE RESISTANT DESIGN AND RISK REDUCTION BY DAVID DOWICK This book is based on global research and development work over the last 50 years or more. Many advances have been made since the previous (2003) edition, and there is every sign that this rate of progress will continue apace in the years to come. Compiled from the author’s wide experience in earthquake engineering, this key text provides an excellent treatment of the complex multidisciplinary process of earthquake resistant design and risk reduction. New topics include the creation of low-damage structures and the spatial distribution of ground shaking near large fault ruptures. Sections on response of buildings to differential settlement in liquefaction and performance-based and displacement-based design have been revised. CONCRETE PLANET BY ROBERT COURLAND Concrete: We use it for our buildings, bridges, dams, and roads. We walk on it, drive on it, but very few of us know what it is. We take for granted this ubiquitous substance, which both literally and figuratively comprises much of the modern civilization’s constructed environment; yet the story of its creation and development features a cast of fascinating characters and remarkable historical episodes. Library Quiz To go in the draw to win a copy of Concrete Planet: The Strange and Fascinating Story of the World’s Most Common Man-Made Material by Robert Courland answer the following simple question:
Concrete Solutions Our Rockcote MultiStop range of premium construction mortars are designed for ease of use as sandable or non sandable patch, repair, & finishing plasters to achieve the best result over masonry substrates.
Which two companies were named the “Overall Winner” 2013 Earthquake Strengthening Awards for The Royal Society of New Zealand building in Wellington? Email your answer to library@ccanz.org.nz. Entries close Friday 30 September 2013. Congratulations to Philip J. King of Transfield Worley Ltd, who correctly answered the Vol 56 Iss 2 Library Quiz to receive a copy of Earthquake Engineering for Structural Design by Victor Gioncu and Federico Mazzolani.
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www.reseneconstruction.co.nz 0800 50 70 40
News from the Associations CONTACTS New Zealand Ready Mixed Concrete Association Ph (04) 499 0041 Fax (04) 499 7760 Executive Officer: Adam Leach President: Jeff Burgess www.nzrmca.org.nz New Zealand Concrete Masonry Association Ph (04) 499 8820 Fax (04) 499 7760 Executive Officer: David Barnard President: Mario Fontinha www.nzcma.org.nz Precast NZ Inc. Ph (09) 638 9416 Fax (09) 638 9407 Email: ross.cato_precastnz@xtra.co.nz Executive Officer: Ross Cato President: Paul Cane www.precastnz.org.nz New Zealand Concrete Society Ph (09) 536 5410 Fax (09) 536 5442 Email: concrete@bluepacificevents.com Secretary/Manager: Allan Bluett President: Jason Ingham www.concretesociety.org.nz New Zealand Master Concrete Placers Association Ph (07) 575 3214 Fax (07) 575 3618 Email: office@mcpa.org.nz www.mcpa.org.nz
PRECAST NEW ZEALAND INC. (PCNZ)
Plant Certification Program The purpose of the Precast NZ Plant Certification Program is to provide project specifiers, head contractors, building owners and others, with a level of confidence that products purchased from a Precast NZ Certified Plant are supplied from an established operator and a plant with appropriate manufacturing facilities, quality assurance programs, levels of expertise and experience. Whether precast concrete is required for Architectural, Structural, Cladding, Civil Engineering or any other purpose, purchasing from a Precast NZ Certified Plant ensures that it has been manufactured by a plant with quality procedures in place that have been audited by an independent and accredited inspection body, such as those on the JAS-ANZ Register. Anyone is able to label themselves a “Concrete Precaster”. A few moulds on a bit of spare land is all that is required to precast concrete. There are concrete precasters, and then there are Precast NZ Certified Precasters. Purchasing from a member of Precast NZ ensures the product is manufactured in an established plant with proper facilities and experienced personnel. Members have significant investment in their plants and have long term goals. They have an interest in quality product and ensuring customer satisfaction to build their reputation and obtain repeat business. Purchasing from a Precast NZ Certified Plant also adds a further layer of assurance with independent third party audit of quality systems and a more detailed inspection process. Precast NZ Certified Plants have a significant investment in manufacturing facilities, quality systems, workforce training with the objective of producing quality product. Cheaper products may be produced without these facilities, but lowest tendered price should never be the sole consideration. The competitive tender process puts pressure on builders to select the lowest price offered. An experienced builder would hesitate before purchasing ready mixed concrete from an uncertified plant. Similar caution should be exercised before purchasing precast concrete from an uncertified plant. Contractors have accepted the lowest price for precast concrete only to find issues with quality, performance, delivery, program and sometimes all of these on the one contract causing a major embarrassment for all involved, as well as added costs. Quality can be assured by specifying “All Precast Concrete shall be sourced from a Precast NZ Certified Plant”. The following plants are on the Precast NZ Certified Plant Register: • HEB Precast, Mt Maunganui • Wilco Precast, Auckland • Litecrete NZ, Auckland • Formstress Precast, Waiuku • Stresscrete Northern, Auckland A number of other plants have applications currently under consideration.
Look for plants displaying the “Certified Plant” logo.
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