SIMULATION TECHNOLOGY SUPPORTS GROUND-BREAKING RESEARCH INTO WIND EFFECTS ON HOMES & LOW-RISE BUILDINGS
27 April 2005 - Cambridge Consultants

* world's first realistic home simulation facility – 'The Three Little Pigs' - will deliver better protection against extreme weather

* research targets huge global problem - weather damage costs £700m pa in the UK alone and hurricane damage is typically measured in billions

The research is expected to lead to more formalised techniques for weather-proofing low-rise buildings which, unlike their high-rise counterparts, are 'non engineered' and tend to use vaguely-defined structures. The research will help to deliver protection against evolving weather hazards by providing the know-how to improve building codes and quality control strategies.

'No one has attempted real-world wind simulation on this scale before, so much of the instrumentation will be developed specially for the application', says Eric Wilkinson, head of Cambridge Consultants' Products and Systems Business Unit. 'One of the key challenges is the creation of a custom control system architecture to handle the large number of interconnected wind simulators, and deliver the real-time performance required.'

Realistic wind simulation will be provided by pressure boxes that are able to apply positive or negative wind forces over a +5 to -20 kilopascals range (5 kilopascals equates to a weight of around 500kg for every square metre of roof). This is combined with a fast-acting valve system that allows the simulated wind pressure to reverse direction at rates up to seven times a second. The University of Western Ontario's deep understanding of wind patterns will use this technology to create and apply realistic 'wind profiles' onto full-size structures - beginning with a full-size two-storey, pitched-roof dwelling. Surrounding the space for test structures is a reaction frame, which provides mountings for the pressure boxes. All this equipment will be housed in a hangar-style building large enough to accommodate structures of up to three storeys, and which slides on rails to expose structures to the natural environment.

Cambridge Consultants won the development contract because of its unique expertise in this area, gained from work in the late 1980s on the UK Building Research Establishment 'Brerwulf' project. At that time, working to a BRE design concept, the consultancy developed a large fan-driven wind simulation panel - measuring around 3 metres square - which provided a mechanism to test roofing systems and cladding.

The same basic wind generation technology, which uses high-performance fans, will be used in 'The Three Little Pigs' pressure boxes. However, for this application, a modular range of box sizes is being developed to enable complex building shapes to be handled. Each box will additionally feature a sophisticated control and networking system that will allow the complex time- and spatially-varying wind effects of the real world to be realistically applied. This scheme will allow up to 100 interconnected pressure boxes to be controlled in real-time, supporting system sizes large enough to test complete low-rise buildings.

The leading wind-engineering consultancy RWDI-Anemos, whose Director Nicholas Cook was one of the designers of the seminal Brerwulf project, is helping Cambridge Consultants to develop the new pressure boxes and control scheme, by providing expert local advice on wind loading effects.

Paul Freathy, Managing Director of RWDI-Anemos, comments: 'Damage to non-engineered buildings remains a significant financial burden on the economy. Although individual incidents are often minor, insurance statistics show that weather damage averages out to about £700 million per year in the UK alone. RWDI Anemos is delighted to be able to contribute to this important research project; using our knowledge of the Brerwulf concept and expertise in wind loading and failure studies to help develop better buildings for the future.'

Dr Michael Bartlett, Associate Professor at The University of Western Ontario and Principal Investigator of 'The Three Little Pigs Project', comments: 'The entire research team is delighted to be working with Cambridge Consultants. We are confident that with the combination of Cambridge Consultants and RWDI-Anemos we are working with the most qualified group in the world to develop this complex system.'

Cambridge Consultants will deliver the wind simulation pressure boxes in mid 2005.

To download high resolution images click below:

The Three Little Pigs Project at The University of Western Ontario (London, Ontario, Canada). In 1992, Hurricane Andrew hit south Florida, destroying 20,000 houses and causing US $30 billion in damage. If the storm had tracked 50 km further north, estimated damage would have exceeded US $100 billion. The Three Little Pigs facility will permit, for the first time anywhere, the application of realistically simulated time and spatially varying wind loads to full-scale houses and light-frame structures including sheet steel buildings, in a controlled manner, up to failure. This will permit an assessment of the integrity of the overall structure of the building, the pathways by which the load is transmitted through the structure to the ground and the performance of individual building components as part of the whole construction. Simulated snow loading will also be investigated. In addition, the facility will be used to assess the factors influencing the ingress of moisture due to wind-driven rain and the development of harmful mould growth under realistic environmental conditions. Further, information on human error during the construction process will be collected and its impact on the potential damage and failure will be analyzed. These will all be breakthrough developments to the current state-of-the-art.

Houses and light-frame buildings are complex structures because of their highly redundant and vaguely defined structural systems. For example, resistance to lateral movement is largely derived from the drywall nailed to both load-bearing and non load-bearing walls inside the structure. The infrastructure will generate necessary data to validate the next generation of computational analyses of houses and light frame buildings that will accurately predict behaviour up to failure. Full-scale component tests and even the static loading of complete structures do not adequately predict true behaviour under transient peak wind loads that fluctuate dramatically over the surface of the building. Thus, the precise response mechanisms up to failure are not yet known.

The goal of this research is to develop anticipatory mitigation strategies to protect people's homes from destructive environmental forces, by: (1) modifying building codes to advance safer, yet less expensive houses; (2) working with the insurance industry and government to develop implementation strategies; (3) developing cost-effective mitigation devices for retro-fitting the existing housing stock; and (4) developing quality-control strategies to minimize human error in construction.

This material is taken from www.eng.uwo.ca/research/ttlpp/. A more detailed description may be found there.

The University of Western Ontario (London, Ontario, Canada) is a vibrant centre of learning with more than 1,700 faculty members and 32,000 undergraduate students. Through its 12 Faculties and Schools, and three affiliated colleges, the University offers more than 60 different degree and diploma programs. Research is an integral part of the University's mission, and Western is home to one of Canada's strongest research constellations in the area of biomedical research. With nearly $190 million in annual funding, Western ranks as one of the top research intensive universities in Canada. www.uwo.ca

Cambridge Consultants has for over 40 years enabled its clients to turn business opportunities into commercial successes, whether launching first-to-market products, entering new markets or expanding existing markets through the introduction of new technologies. With a team of over 200 engineers, scientists and consultants in offices in Cambridge (UK) & Boston (USA), it is able to offer solutions across a diverse range of industries including healthcare, industrial & consumer products, automotive, transport, energy & wireless communications.

RWDI-Anemos Consulting Engineers is one of the UK's leading wind engineering consultancies and part of the RWDI Group, the largest such consultancy in the world. Its expertise lies in solving construction design and performance problems relating to the effect of wind on buildings and the environment, as well as the design and performance of construction products. The company, which boasts more than 100 years' combined industry experience, including work on the world's tallest buildings, also offers training in the principles of wind-engineering, the appropriate use of codes of practice and software development.

http://www.cambridgeconsultants.com/

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