Abstract
The structure is composed of a superstructure and foundation. The superstructure and foundation are designed separately in the present design method, but it is an ideal that the optimum design of a structure is carried out as one system. The present paper describes the procedure of optimization for system reliability of spoil-supported structure. Each optimum design alternative of a superstructure and foundation is decided by minimizing the expected total cost as a whole. The plate girder bridge constructed on the poor ground is examined as a case study. The optimum safety factors of the main girders and the foundation are decided from the view point of system reliability.
