Rebuilding in the aftermath of Hurricane Sandy, homeowners might consider the advice of Rima Taher, an expert in the design of low-rise buildings for extreme winds and hurricanes. Taher, a civil and structural engineer who teaches at the NJIT College of Architecture and Design, has offered for years her thoughts on best building design and construction practices in hurricane-prone regions.Taher’s research focuses on the design of low-rise buildings for high winds and hurricanes. She was recently trained in the post-disaster safety evaluation of buildings in the aftermath of earthquakes, hurricanes and floods by the Structural Engineering Institute of the American Society of Civil Engineers in cooperation with the California Emergency Management Agency and the Applied Technology Council. She will soon be registered as a California Emergency Management Agency Safety Assessment Program Evaluator. “Certain home shapes and roof types can make a big difference,” is a common refrain in all her work. ATTENTION EDITORS: To interview Taher, contact Sheryl Weinstein at 973-596-3436 firstname.lastname@example.org.
Her recommendations include the following:
Design buildings 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 the gable roofs with two slopes. Gable roofs 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 said. To combat uplift, she advises connecting roofs to walls strongly with nails, not staples and hurricane clips. Different roofing systems perform differently under hurricane conditions. Tile roofs may not be the best material in sensitive regions because they can loosen and become wind-borne debris, threatening other structures.
Aim for strong connections between the structure and foundation. Structural failure-- one structural element triggering the collapse of another—can be progressive.
Hurricane shutters can protect glazing from wind-borne debris. Various designs are available.
Roof overhangs are subject to wind uplift forces which could trigger a roof failure. In the design of the hurricane-resistant home, the length of these overhangs should be limited to about 20 inches.
The design of the researched cyclonic home includes simple systems to reduce the local wind stresses at the roof’s lower edges such as a notched frieze or a horizontal grid. Install the latter at the level of the gutters along the homes’ perimeter.
An elevated structure on an open foundation reduces the risk of damage from flooding and storm-driven water. All foundation piles must be strengthened by bracing and should penetrate deep enough into the soil to reduce the risk of scour.
Last year, Taher was an invited speaker at the Annual Conference of Construction Specifications Canada (Devis de Construction Canada) in Montreal. In 2010, she addressed a conference hosted by the Inter-American Development Bank's Education Division in collaboration with Chile's Ministry of Education in Santiago, Chile. Her paper--designing and strengthening educational facilities against the risk of earthquakes and hurricanes—appeared in the conference proceeding. The event highlighted advances in school infrastructure in Latin America and the Caribbean, and the private sector’s financial role.
In the aftermath of the earthquake in Haiti, Taher, prepared a document for Architecture for Humanity about best building practices. She also has cooperated with wind researchers at Tokyo Polytechnic University, Japan, to help develop and translate into French a brochure for UNESCO to help Haitians prepare for the hurricanes. UNESCO distributed the brochure in Haiti.
In 2007, Taher’s article about the design of low-rise buildings for extreme wind events appeared in the Journal of Architectural Engineering of the American Society of Civil Engineers. Another article on improved building practices for hurricanes appeared in Caribbean Construction Magazine in July of 2009.