Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Civil and Environmental Engineering


Dr. El Damatty A. A

Second Advisor

Supervisory Committee


Owing to their excellent structural characteristics, aesthetic appearance, low maintenance cost, and efficient use of structural materials, cable-stayed bridges have gained much popularity in recent decades. Stay cables of a cable stayed bridge are post-tensioned to counteract the effect of the bridge dead load. The solution for an optimum distribution of post-tensioning cable forces is considered one of the most important and difficult tasks in the design of cable-stayed bridges. A novel approach that utilizes the finite element method, B-spline curves, and real coded genetic algorithm to determine the global optimum post-tensioning cable forces is developed. The effect of geometric nonlinearity on the determination of the post-tensioning cable forces is assessed. The study is further extended to develop the first surrogate polynomial functions that can be used to evaluate the post-tensioning cable forces in semi-fan cable stayed bridges. The developed post tensioning functions are then used to investigate the optimal geometric configurations, which lead to the most uniform distribution of the post-tensioning cable forces. Details of an optimization code developed in-house specifically to optimize the design of composite cable-stayed bridges with semi-fan cable arrangement are then reported. The optimization design code integrates a finite element model, the real coded genetic algorithm, the post tensioning polynomial functions, and the design provisions provided by the Canadian Highway Bridge Design Code. An extensive parametric study is then conducted using this optimization code to develop a database for the optimum design of semi-fan cable stayed bridges. The database covers bridge lengths ranging from 250 m to 700 m. It describes the variations of the optimum design parameters, such as the main span length,height of the pylon, number of stay cables, and cross-sectional dimensions with the total length of the bridge.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.