EVALUATION OF SYSTEM-RELIABILITY METHODS FOR CABLE-STAYED BRIDGE DESIGN

Probabilistic system-reliability methods have the potential to assist designers in better understanding the ultimate global behavior of bridges, thus leading to more economical, rational, and reliable structures. Nonetheless, these techniques are not currently broadly used in North American bridge engineering practice. Using a sample cable-stayed bridge design, a study is conducted to assess the practicability of system-reliability analytical methods to assist in the design of cable-stayed bridges. Ductile and brittle cables are considered in series and mixed system analyses, respectively. The sample bridge selected is found to be very reliable; the most likely failure mode identified is somewhat counterintuitive. More importantly, considerable insight into global ultimate behavior is provided by these analyses, and the effect of various design assumptions on global structural safety can be assessed. Some obstacles to the transfer of system-reliability procedures to the state of practice are identified.