Stochatic analysis of cable-stayed bridges

SUMMARY STOCHASTIC ANALYSIS OF CABLE-STAYED BRIDGES Cable-stayed bridges have become popular for long span bridges in the recent years. While the first cable-stayed bridges were generally built in nonseismic zones, recently they have also been constructed in zones of high seismicity. This is why the dynamic analysis of cable-stayed bridges have become extremely important. Dynamic analysis of structures, including cable-stayed bridges, are based on deterministic such as response spectrum and time history analysis. For deterministic analysis, all the dynamic parameters, initial conditions and dynamic excitations are assumed to be exactly known. But, earthquake ground motions are random in nature and it is impossible to predict these motions exactly. So, dynamic analysis of structural systems should be carried out using stochastic analysis, in which random forces are demonstrated in terms of statistical averages and probability. In this study, the Jindo Bridge which was built in South Korea in 1982 is choosen as a practical example to apply the stochastic method. With this aim, the historical development of cable-stayed bridges in terms of construction and analysis are explained in the chapter one. Then the basic principles and the formulation of stochastic analysis of linear systems are presented. The basic features of cable-stayed bridges and their members are also included in the chapter one. Jindo bridge is introduced and it is mathematically modelled in the chapter two. While the findings obtained from the stochastic analysis of the cable-stayed bridge are presented and discussed in the chapter three, conclusions drawn from the stochastic analysis of a chosen bridge and suggestions are presented in the chapter four. Key Words: Cable-Stayed Bridge, Dynamic Analysis, Stochastic Analysis, Random Process, Earthquake, Power Specktral Density Function, Mean of Maxima Value, Frequency of Occurence, Probability Distribution Function. VIII