Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Dr. Ashraf El Damatty

Abstract

Past high speed wind events have exposed the vulnerability of the roof systems of existing light-framed wood structures to the uplift forces resulting from high speed winds, contributing greatly to economic and human loss. This research focuses on developing a retrofit system to increase the uplift capacity of these structures using numerical and experimental techniques. The proposed system provides the uplift forces an alternate load path to the ground, reducing the demand placed on the weak, nailed connections within the structure. A three-dimensional finite-element model of a roof system of full-scale wood structure has been developed. The model is compared to the results of a full-scale experiment in both the linear and nonlinear ranges, proving the ability of the model to predict the deflected shape of the structure. The numerical results identify the importance of considering the nonlinear plastic damage that occurs to the roof-to-wall connection under realistic wind loading. The validated numerical model is then extended to include the proposed retrofit idea. A rigorous analysis of the behaviour of the structure after application is then carried out. The model predicts that application of the retrofit system can increase the critical mean hourly wind velocity from 38m/s to 50m/s. An experiment has been conducted, proving the retrofit system is effective at increasing the uplift capacity of light-framed wood structures. The results of the experiment have been used to validate the assumptions of the numerical model, proving that the model captures the structural interaction between the retrofit and truss systems.


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