Author

Ziran Hu

Date of Award

2009

Degree Type

Thesis

Degree Name

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Drs. Hanping Hong

Second Advisor

J. Peter C. King

Abstract

The study is focused on two aspects relating to the bridge design: the gust factor and wind load factors. The concept and the assessment of the gust factor developed by Alan G. Davenport are essential for bridge design under buffeting forces. However, systematic parametric investigation of the standard deviation of fluctuating wind-induced bridge responses and the gust factor, by considering the spatio-temporal varying along and cross winds and aerodynamic damping has not be given, although a simple to use approximate equation is available. Such an investigation is given in the present study by including/excluding the aeroelastic self-excited forces. The results obtained are used to assess the bias associated with this simple approximate equation, and can be adopted by bridge design codes for predicting the gust factor.

Since the gust factor depends on the dynamic structural characteristics and the characteristics of wind speed, wind load factors are calibrated by incorporating this dependency for both the simple procedure and detailed procedure in the current Canadian Highway Bridge Design Code (CHBDC). Based on the calibration results by considering a target reliability index of 3.5 for a service period of 75 years, a wind load factor of 1.4 for simple procedure, and an equation to evaluate wind load factor for detailed procedure are recommended for the future edition of die CHBDC. Furthermore, the calibration results indicate that an increase of dead load from 1.20 to 1.25 for the ULS combination 4 given in the current CHBDC is desirable to achieve increased reliability consistency in the bridge design

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