LIGHTWEIGHT DEFORMABLE floors which would sag under the weight of debris falling from above could provide a practical way to reduce the risk of progressive collapse, a leading safety engineer claimed this week.
Consultant Arup fire safety director Peter Bressington said that increasing each floor's ductility offered an economic solution. 'Even if it sagged to the point of meeting the floor below, this would still be safer than the sort of failure we saw at Ronan Point in 1968 and the World Trade Center last year, ' he added.
Arup's extreme events mitigation task force has been considering the problem of progressive collapse ever since the WTC tragedy. Some voices in the industry have argued that some things just can not be designed against. Bressington disagrees. 'We believe there are always improvements that can be made. We need to show how we as an industry are combating increased terrorist threat and instil confidence in the public that we can make their buildings safer.'
Arup will also have to develop floor connection design to allow greater movement without failure. This is under way at Arup's Hong Kong office, which has strong experience of high rise design.