Structural engineer Rima Taher, PhD, an expert in the design of low-rise buildings that can withstand extreme winds and hurricanes and a university lecturer in NJIT’s College of Architecture and Design, was recently elected chair of the structural technical group of the Northern New Jersey branch of the American Society of Civil Engineers (ASCE). Taher represented this group late last month at a leadership conference in New Orleans sponsored by ASCE’s Structural Engineering Institute. The conference included training, discussions and a tour of the US Army Corps of Engineers West Closure Complex Pump Station Project. The complex is part of the hurricane and storm damaged risk reduction system for southwest Louisiana that was authorized and funded by Congress following the 2005 hurricane season.Taher speaks often about how home shapes and roofs can impact high wind and hurricane events. She advocates buildings that are designed with square, hexagonal or even octagonal floor plans with roofs of multiple slopes such as a four-sloped hip roof. These roofs perform better under wind forces than gable roofs with only two slopes. Gable roofs, she says, are common only because they are cheaper to build. Research and testing demonstrate that a 30-degree roof slope will have the best results.
Wind forces on a roof tend to uplift it. “This explains why roofs blow off during extreme wind events,” Taher says. To combat uplift, she advises connecting roofs to walls strongly with nails, not staples and hurricane clips. The use of hurricane clips is recommended.
The choice of roofing matters, too. Different roofing systems perform differently under hurricane conditions. In tile roofs, loose tiles often become wind-borne debris threatening other structures.
There should always be a strong connection between the structure and foundation. Structural failure can be progressive with one structural element triggering the collapse of another. Hurricane shutters can protect glazing from wind-borne debris. Various designs are available.
Taher, who is a frequent speaker about strengthening infrastructure, spoke on the topic of designing for hurricanes and earthquakes at the annual conference of Construction Specifications Canada this past May in Montreal. She also spoke last year in Santiago, Chile about designing and strengthening educational facilities against the risk of earthquakes and hurricanes. The Inter-American Development Bank's Education Division in collaboration with Chile's Ministry of Education sponsored the conference.
In 2007 Taher’s article about the design of low-rise buildings for extreme wind events appeared in ASCE’s Journal of Architectural Engineering. Another article by her on improved building practices for hurricanes appeared in Caribbean Construction Magazine in July of 2009.