By Emmanuelle Landais, Senior Reporter www.gulfnews.com
Dubai: Buildings in the UAE could withstand an earthquake measuring up to 5.5 on the Richter scale.
To ensure that high-rises have the ability to withstand an earthquake, all buildings in Dubai over four storeys high are required to adhere to the internationally-recognised Uniform Building Code 97 (UBC).
Lance Vigil, design manager for ALEC Construction, who is currently working on the Yas Island Water Park, said that the UAE follows the UBC as well as International Building Code (IBC).
No fault zones
“These are general regulations for seismic, or lateral, loads — only specific jurisdictions say, in California, have specific seismic codes. There really are no fault zones around the Arabian Peninsula so it makes sense that no additional requirements are there, and this is pretty typical around the world,” Vigil said.
A city’s vulnerability to earthquakes is mapped based on the Seismic Zone Factor, or ‘Z-factor’, which corresponds to ground motion and the chances of that movement increasing in 50 years.
Seismic zones are categorised on a scale of 1 to 4. California, Tokyo and much of Japan is classified as Zone 4 — the highest risk of a major earthquake.
Known crustal faults
According to Dubai Municipality, Dubai is mapped as a Zone 0 but the building codes follow a Zone 2A rating — for areas not typically associated with a particular fault zone. A Zone 2B classification indicates an association with known crustal faults.
Apart from earthquakes, the wind factor must be considered in the engineering stage when designing tall buildings.
“New buildings here would generally handle seismic loads as their structural base is mainly reinforced concrete, which handles lateral loads very well, although older buildings built cheaply may not fare so well,” Vigil said.
Green building measures
“Green building measures don’t address structural issues, just life-cycle and general sustainable ‘good for the environment’ issues.”
Gulf News had earlier reported that the Burj Khalifa, the world’s tallest structure, is supported by a large reinforced concrete mat, which is in turn supported by bored reinforced concrete piles. The design is based on extensive geotechnical and seismic investigations and analysis.
The expected effects of a seismic event on the tower are modest, according to Skidmore, Owings and Merrill, the firm behind the tower’s design.
As is the case with most tall buildings, the long vibration period of the Burj Khalifa is quite different from the high frequency vibrations of an earthquake and therefore the structure will not generate large force in a seismic event.