By Monika Grzesik
Experts call for substantial reduction to the region's building code seismic design provisions.
Experts are calling for the seismic design provisions of building codes in the region to be substantially reduced. A new seismic hazard assessment for the Gulf presented at the Dubai Municipality last week indicated that the seismic hazard in the region is significantly lower than the Uniform Building Code (UBC) 2A classification currently in use, and suggests the a less conservative Zone 1 code be introduced.
"We haven't had an earthquake above magnitude 5.1 here," said Angus McFarlane, technical director at Hyder Consulting, who carried out the assessment. "Magnitude 5.0 is just on the fringes of being structurally significant."
McFarlane carried out the hazard assessment because all available studies in the region were found to be unreliable and contradictory with seismic risk in the Gulf, ranging from very high to almost aseismic. McFarlane concluded that the region is at low risk of a large magnitude earthquake and added that building codes should be adjusted to reflect this. "All reasonable risk for the Emirates would suggest that a Zone 1 coding would be adequate. It's more than enough, it's a very conservative assumption."
While high rise structures are being constructed in accordance with earthquake codes, it is low and medium height buildings that are most at risk from seismic activity. "People are fixated that tall buidings are at risk, but in high rise buildings you get a low force, while in low rise buildings you get a high force. If you intend to design for eathquakes it is important that all buildings should be designed for earthquakes," said McFarlane.
Dubai Municapilty is in the process of preparing a new set of seismic codes for Dubai based on data taken from four seismic monitoring stations located around the UAE. According to Dr Boualem Tiliouine, technical advisor at Dubai Municality, the results of the study have been held up due to budgetary constraints.