Performance of Cable-Stayed Bridges: Evaluation Methods, Observations, and a Rehabilitation Case

Abstract

This paper discusses advances in evaluation, health monitoring, and rehabilitation of cable-stayed bridges, and available methods. In the last 2 decades, the writer has contributed extensively to advances in cable-stayed bridge construction, design, and health monitoring. Information gathered from evaluation of the strength and reliability of dozens of stay cable systems worldwide, and health monitoring and inspection of more than 12 cable-stayed bridges in the United States and abroad, have discovered problem conditions that seem to be consistent across many types of cable-stayed bridges and stay cable designs, and have helped toward formation and evolvement of a unified approach for in-service evaluation and problem solving of these aesthetic structures. A case study related to evaluation and rehabilitation of the Luling Bridge in Louisiana, for which the new approach has been implemented almost entirely, is also described. The bridge evaluation process, and cable replacement design and its implementation, contain unique aspects and are the first attempted in North America. The cable replacement design accommodated an extraordinary construction sequence to address constraints on space and traffic flow. Temporary cables minimized stress variation and allowed for the live load without restriction. The new cable system allows individual strand installation and tensioning, and is expected to facilitate future inspections and replacement.