Research on reasonable value of target reliability index for steel main girder of cable-stayed bridge considering durability

Abstract

This article studies the relationship between the target reliability index and the design life of the main girder of a long-span cable-stayed bridge to provide a theoretical basis for the design of steel girders for such an application. The changes of the bending section modulus under atmospheric corrosion and the residual ultimate stress of the section of a steel box girder under alternating loads are discussed. A resistance attenuation function for a steel girder of a cable-stayed bridge to predict the resistance change of a steel box girder over the service period is proposed, and the change characteristics of the time-varying reliability index of a steel box girder of a cable-stayed bridge are studied. By analysing the relationship between the time-varying reliability index and the evaluating benchmark value of the reliability index, the time point of maintenance and reinforcement is predicted. Based on the change over time of the difference between the time-varying reliability index and the evaluating benchmark value of the reliability index, the relation function between the target reliability index and the service lifetime of a bridge considering resistance attenuation are provided.

Keywords:

• Cable-stayed bridge
• steel box girder
• target reliability index
• resistance attenuation
• time-varying reliability
• reliability assessment

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was jointly supported by the National Key Basic Research Program of China (973 Program) (Grant no. 2015CB057706), the National Natural Science Foundation of China (Grant no. 51108044), the Natural Science Foundation of Hunan Province (Grant no. 2018JJ2443), and the Systematic Project of Guangxi Key Laboratory of Disaster Prevention and Structural Safety (Grant no. 2016ZDK014).