Fragility assessment of wood sheathing panels and roof-to-wall connections subjected to wind loading

The performance of the wood-frame buildings after tornadoes has shown that the majority of the wind damage resulted from building envelope failure most typically due to the loss of the roof.To assess the performance and the reliability of low-rise wood-frame residential buildings with a focus on the roofs,fragility analysis can be used to estimate the probability of failure of a roof when constructed with specified nails and sheathing sizes.Thus,this paper examines the fragility of specific types of nails,roof-to-wall(RW)connection details,and sheathing sizes based on the damaged roofs that were previously assessed in the Dunrobin area in Ottawa(Ontario)that was hit with an Enhanced Fujita(EF3)tornado on September 21,2018.The presented fragility analysis considers four scenarios,including different sheathing and nail sizes.Dead loads,wind loads,and resistance on the sheathing panels were compiled and analyzed to determine the failure of the examined roofs.The eight fragility models suggest that the safest roof sheathing(RS)is the 1.22 m×1.22 m sheathing panel with 8 d nails,and the safest RW connections is achieved by using H2.5 hurricane clips.