x Abu Dhabi, UAESaturday 22 July 2017

Simple design keeps towers quake-proof

Abu Dhabi's modern skyscrapers may be more susceptible to earthquake damage, says a seismic expert invited to teach building codes.

ABU DHABI // The soaring towers being built in the capital may be prone to earthquake damage, and designers should learn to "keep it simple" and safe, a leading seismic expert told municipal executives and developers.

Engineers should go back to basics, said SK Ghosh, who spoke this week at a seminar on new building regulations. "I mean 'simple' as opposed to the fancy things that you're looking at all kinds of curves and corners and offsets," Mr Ghosh said. "These are all detrimental to good earthquake performance." The challenge, Mr Ghosh said, is that architects and building owners want to continue dreaming up whimsical structures that push architectural boundaries.

The Department of Municipal Affairs (DMA) invited Mr Ghosh, who is based in Chicago, to train public and private engineers in the International Building Codes being adopted by the emirate. By early next year, all new structures must comply with the guidelines, which include everything from fire codes to seismic design regulations. The new guidelines, which are based on US standards, should mean safer structures, said Mr Ghosh, a member of the Board of Directors for the US Earthquake Engineering Research Institute.

He said uniformity was much needed, as the emirate currently uses a mishmash of building codes from around the world. "There is incompatibility, so [building engineers] will do concrete design by the British code, and then take earthquake process by an American code, but the two don't go together," he said. "Given an abnormal situation, which an earthquake is, the engineer may not fully understand the implications of this incompatibility, and he may be doing things that are not quite right.

The cost of adding earthquake-resistant measures to a building is typically about one or two per cent of the structural cost, Mr Ghosh said. Most of the expense is for "detailing", which might involve reinforcing concrete columns with a lattice of steel bars and hooks for stabilisation, he said. Although the International Building Codes will not apply to existing buildings, significant expansions might require designers to comply with the updated codes either for the new addition or the entire structure.

Ali Bukair, a policy consultant for the DMA who helped put together the new guidelines, said the new codes would be updated frequently to ensure better, safer and greener buildings in the emirate. "We'll try to identify things specific for this region and come up with our own customised Abu Dhabi code," he said. "When you create a city, you have to have a proper code in place to regulate construction so the public's welfare is being considered. That's really the whole purpose of all this."

Dubai Municipality has seismic building-design requirements for structures that are at least five storeys tall. The structures must be built to hold up under much stronger earthquakes than are possible in this region. Mr Ghosh believes governments across the emirates should adopt the same codes as Abu Dhabi. "For the full benefit of this, the whole country needs to be on the same code," he said. "If Dubai is on one code and Abu Dhabi is on another, much of the purpose is defeated."

Mr Bukair agreed, and called for other countries in the region to follow Abu Dhabi's lead. "I'm not talking about only the emirates, but the entire region should be developing and implementing these international codes," he said. "By early 2010, our conditions will change drastically and we'll have a unified set of codes ready. We only have to get people used to it." The session on seismic guidelines attracted about 20 engineers to the Armed Forces Officers Club and Hotel on Wednesday. The meeting "really showed the challenges ahead", said the director for a major contract company.

One concern is that educating all the engineers in Abu Dhabi about the new regulations could take some time. "This is not going to happen by the beginning of next year and people know it," said Brian Sweeney, an engineer at Ramboll, Whitby and Bird, a consultancy that has worked on skyscrapers in Dubai and Abu Dhabi, as well as structures in the Ferrari World theme park on Yas Island. "It's high time they updated the code." Mr Sweeney said.

"This is as good a time as any, especially considering the downturn, because it will mean there is more time to [take courses like this] as opposed to the breakneck speed we were working at before." mkwong@thenational.ae jgerson@thenational.ae