WASHINGTON, Sept. 14 (UPI) -- U.S. building codes meant to deal with disasters such as earthquakes or hurricanes but not both at once underestimate risks of multiple hazards, a report says.
Following a natural one-two punch of an earthquake and hurricane that hit the country's East Coast, researchers from the National Institute of Standards and Technology warn such a combination of of seismic and wind hazards can increase the risk of structural damage to twice the level implied in building codes.
Current codes consider natural hazards individually, NIST structural engineer Dat Duthinh says.
If earthquakes are seen as the main threat in a region, then local building codes will focus on seismic load safety requirements.
Similarly, in hurricane-prone areas codes will require construction to withstand a certain maximum wind speed.
Duthinh says this compartmentalized approach can be dangerous.
In areas prone to both seismic and wind hazards, such as South Carolina, the risk that design limits will be exceeded can be as much as twice that of regions where only one hazard occurs, he says.
Therefore, buildings designed to meet code requirements in these double-jeopardy locations "do not necessarily achieve the level of safety implied," Duthinh and colleagues say in an article published in the Journal of Structural Engineering.