Semi-analytical solution for gable roofs under uplift wind loads: Fid-Bau Portal

Semi-analytical solution for gable roofs under uplift wind loads

Enajar, Adnan / El Damatty, Ashraf / Nassef, Ashraf

Highlights • The paper focuses on the uplift response of existing houses located in the hurricane-prone areas. In these houses, the old weak toe-nail detailing is used to connect the roof to the walls. • The paper provides a computationally efficient semi-analytical model that can predict the behaviour of roof houses under uplift wind load taking into consideration the nonlinearity of the roof-to-wall connections and the spatial variation of the uplift wind pressure. • The developed semi-analytical model was validated using results of experiments conducted previously on a house under real wind loads as well as using three-dimensional finite element modeling. • Because of its computational efficiency, the developed semi-analytical model can be used to conduct reliability analysis of gable roofs under uplift pressure.

Abstract A common type of failure observed during hurricane events is the detachment of the roofs of light-frame wood houses because of the inability of the roof-to-wall connection (RTWC) to transfer uplift wind loads acting on the roofs. This paper introduces a computationally efficient procedure for conducting nonlinear analysis of the roofs to determine the connections forces using a semi-analytical solution. The new procedure simulates an entire roof as a continuous beam resting on elastic supports through the use of statically indeterminate slope deflection equations that include shear deformations. It accounts for the two-dimensional spatial variation of the uplift wind pressure. The new model was validated against a three-dimensional finite element model and also through a comparison with the results of experimental testing of a gable roof house previously conducted at the University of Western Ontario, Canada. The model was used to determine the load sharing among the trusses under a realistic load. It was also used to assess the adequacy of using the tributary area method under a code load. Based on the validation results, the semi-analytical solution model demonstrated an ability to predict the response of a roof under uplift wind loads that vary both in time and space. The main advantage of the new model is the efficient computational time compared to three-dimensional finite element modeling. As such this model can be used in the future for conducting probabilistic analysis of the roof taking into account the variation of the connection properties.