Design audit of the Phu My cable-stayed bridge, Vietnam

Abstract

Details of selected analyses and design checks conducted in connection with the design audit of Phu My cable-stayed bridge in Vietnam are presented. The project is briefly introduced with regard to the contractual set up and the principal design standards. Techniques used for the analyses are discussed with reference to the provisions of the governing design standards. Details of the advanced finite-element analyses conducted in order to facilitate the design checks of the permanent works under temporary as well as in-service conditions are then presented. It is shown how the scope of the analyses was integrated to interface non-linear staged construction analysis, incorporating time-dependent effects, with the analysis for extreme load events under US design codes. Details are provided in particular for staged construction analysis, ship impact analysis, dynamic response spectrum analysis and cable stay fracture analysis. In addition, cable stay fatigue, cable stay replacement and vehicular live load effects are also discussed. A brief description of wind analysis, particularly with regard to construction stage wind buffeting, is also presented together with the considerations taken on board for other environmental factors such as temperature and humidity. The importance of appropriate engineering experience in the management and validation of large analytical models is also discussed before presenting selective elements of the structural design checks. The paper is concluded with some thoughts on the role of advanced analyses in prospectively investigating the long-term sustainability of the structure through its life cycle.