Reliability analysis of geometrically nonlinear structures with application to suspension bridges

This thesis concentrates on an investigation on component and system reliability analysis of Geometrically Nonlinear elastic Structures (GNS) with application to suspension bridges. Suspension bridges in Japan are designed based on the allowable stress design concept. This concept leads to bridges with nonuniform safety levels. In this study, reliability-based concepts and methods are used for the design of geometrically nonlinear structures. In this context, the design of the superstructure of the Innoshima Bridge is discussed.; The geometrically nonlinear finite element formulation for truss and frame elements is derived according to Total Lagrangian formulation. To implement the finite element reliability analysis of GNS, the linkage of a system reliability analysis program RELSYS with a deterministic finite element analysis program FEAP is created. The results obtained in analyzing GNS by using first-order reliability method are compared with those obtained by Monte Carlo simulation and second-order reliability method.; To compute the system reliability of GNS, the reduced stiffness matrix and equivalent internal forces of truss elements of GNS are derived. The system reliability analysis of geometrically nonlinear framed structures without using the reduced stiffness matrix and equivalent internal forces is proposed and carried out.; The proposed methodology for reliability analysis of GNS was applied to both idealized and real structures. Using the proposed methodology, the reliability of geometrically nonlinear structures is evaluated in a realistic way. The proposed methodology is intended to be applied to all types of suspended structures, including suspension bridges, cables-stayed bridges, and transmission towers, among others.