Dubai: New wind codes pertaining to high-rise buildings are expected to be implemented in 2013, reinforcing the concept that structures must be able to sustain winds as well as gusts to keep residents inside safe.
“We have been taking a conservative approach to the rules and once the revised wind code is implemented --based on the findings of international researchers -- the requirements will be relaxed,” said Moawya Abdul Rahman, head of the structural engineering unit at Dubai Municipality’s building department.
The wind code that is now in use by the municipality states that structures should withstand a basic wind speed of 45 metres per second for a three-second gust, which is equivalent to 160km/h.
The code has been under review since 2009 andits current draft is based upon ““basic wind speed for design in conjunction with wind tunnel testing.”
In 2003, representatives from RWDI, a Canadian firm of consulting engineers and scientists, carried out a wind climate analysis and gathered data over a span of 20 years, and they collected data from Abu Dhabi, Dubai, Ras Al Khaimah, Sharjah and Qatar.
RWDI’s findings recommended that high-rise structures should withstand a wind speed of 36.4 metres per second, but the municipality is also taking a conservative approach to the recommendation and will use a slightly higher numberof 38 metres per second.
The new code implies that contractors will have fewer costs when constructing skyscrapers, as opposed to the previous code.
Based on the analysis of wind velocities recorded at Dubai International Airport from 1984 to 2008, the basic wind velocity for Dubai was 30 metres per second, which is equivalent to 108km/h.
But once the revised code is implemented, its parameters will be based on a wind velocity of 25 metres per second, which is equivalent to 90km/h. Dubai Municipality not only takes wind into account before approving the structure of buildings but also seismic forces.
According to the Unified Building Code, Abu Dhabi and Dubai are classified as zone zero for seismic forces, yet Dubai Municipality takes precautionary measures and uses regulations for zone 2A, which can resist a force of 5.5 on the Richter scale.
“It all depends on the design of the building and the effect of wind and seismic factors will be checked. By using a mathematical model, we then decide which are the critical factors,” he added.