A concrete building system that died a death in Britain in the 1970s, and then proved immensely popular in the rest of the world, is about to be given a second chance
Natural disasters are a permanent threat in many parts of the world. And as the Asian tsunami and the Iranian earthquake in Bam have shown, many buildings aren’t capable of resisting the forces of nature.
The UK is fortunate in suffering only weak seismic tremors. Yet curiously enough, a precast concrete system developed for Britain’s housing market in the 1970s is now at the forefront of seismic engineering.
The system came from work carried out by the then-named Building Research Station at Garston in Hertfordshire. It was developed as a product by Elcon, a firm based in the West Midlands. It was used to build a few hundred houses in Bristol and South Wales, but when the housing market collapsed in the wake of the recession of the early 1970s, Elcon was forced to look overseas for work.
Over the past three decades, the system has been developed and adapted for projects, including housing in China that can resist earthquakes of up to eight on the Richter scale and 40-storey apartment buildings in Hong Kong that can withstand typhoons.
Elcon’s system is based around moulds that produce L-shaped wall panels that can measure up to 6 m on the long leg, 2.5 m on the short leg and are 3 m high. Each of the moulds can produce seven panels twice within a 24-hour cycle with the aid of a hot oil curing system. The floor slabs are cast in 30 m long moulds.
A typical casting yard would have four floor and four battery moulds with a capacity of producing 1400 L-shaped wall panels and 900 floor slabs a month – equivalent to 110 apartment units.
The panels are rigid because there is no joint between the two legs of the walls. They can also be placed directly on a floor slab without resorting to props. Another feature that gives the system its ability to resist seismic and wind forces is a combination of shear keys and connections that anchor the wall and floor components together.
Since heading overseas, Elcon has built many thousands of houses in the earthquake or hurricane zones of Mexico, Hong Kong and mainland China, Iraq, Russia, and Iran, and now Sri Lanka.
Now this unique method looks like coming home. Ted Whitfield, managing director of Elcon’s international operations office in Malaysia, says there are plans to bring the system to the UK. “We are heavily into design and getting planning permission for key worker housing schemes.” He adds that two sites have been secured and production could start by the end of the year.