Damage prediction of low-rise buildings under hurricane winds

Low-rise buildings are defined as the buildings with a mean roof height less than the least horizontal dimension and less than 18.3 m in ASCE 7-10. They represent the majority of commercial, residential, and industrial buildings. Approximate 90% of the existing low-rise residential buildings are constructed as wood light-frame buildings that are not fully engineered and thus more vulnerable to extreme wind pressures, wind borne debris and rain water intrusion. The resulting hurricane-induced economic loss is primarily attributed to the insufficient performance of building envelope instead of the catastrophic failure of their main structural system for Category 1 to 4 hurricanes. The limitations of the current public hurricane loss prediction models for low-rise buildings motivate the current study. Firstly, the wind loading is estimated by modifying the ASCE 7 or other design provisions that envelope the peak wind pressure in limited building surface zones for design purpose. It is difficult to modify those non-contemporaneous wind pressure coefficients close to realistic simultaneous wind loads accurately and to exclude the structural resonant portion on gust effect factor G that is built in with pressure coefficient Cp in most scenarios defined as ASCE 7-10. Secondly, the empirically prescribed tributary area, load path and load sharing may be reasonable for design on the conservative side, but not suitable for damage prediction that demands accurate instead of conservative load distribution among the entire system. Thirdly, most current standards are developed by obtaining equivalent pressure coefficients that envelope the peak responses calculated from wind tunnel data for a range of assumed structural wind resisting system without appropriate attention on building envelope. Currently, the prediction of the mean recurrence interval for peak structural responses under wind loading is achieved by integrating local meteorology data, wind tunnel aerodynamic database, and refined Finite Element analysis techniques as Database Assisted Design does. Those efforts are mainly focused on main wind force resistance system in the past and are extended to evaluate the building envelope performance in this study. The major objectives of this study include to (1) initiate a Database-assisted damage prediction framework for both main wind force resistance system and components and claddings, (2) collect aerodynamic datasets on scaled models by wind tunnel testing, (3) develop a comprehensive and in-depth 3D Finite Element model for both building frame system and its envelope, and qualitatively validate the analytical model under realistic wind pressures with limited available post disaster reports, (4) numerically predict the detailed structural responses for ongoing quantitative validation against the full scale static tests conducted by Florida International University, and (5) develop the vulnerability curves for a selected roof corner sheathing panel by using a database assisted stochastic finite element modeling approach