Stochastic analysis of cable-stayed bridges subjected to spatially varying ground motions

SUMMARY Stochastic Analysis of Cable-Stayed Bridges Subjected to Spatially Varying Ground Motions Stochastic analysis to correlated support motions is performed on cable-stayed bridges. The ground motion model used in this study accounts for the spatial variability of ground motions, including the effects of incoherence, wave passage, and spatially varying site response. Because of the complex nature of earth crust, the spatial variability of ground motions should be taken into account in the dynamic analysis of long span structures. The thesis prepared with this scope includes the following chapters. In the first chapter, general information, the importance of the matter, previous studies about the subject are given. The finite element formulation of the equations of motion and the basic relations for the random vibration analysis are also presented. In the second chapter, the ground motion model used in this study is given along with the analytical model of the chosen bridge. The flowchart of the modified computer program is also mentioned in this chapter with the eigenvalues and eigenvectors of the bridge obtained from modal analysis. In the third chapter, response values obtained from the spatially varying ground motions are discussed in detail. As the results and recommendations obtained from the analyses are given in chapter four, the references are presented in the next chapter. As a conclusion it is observed that the incoherence, wave-passage and site response effects which define the spatial variability of ground motions, have significant effects on the dynamic behaviour of cable-stayed bridges. Therefore, this spatial variability effects should be taken into account for the dynamic analysis of long span structural systems like cable-stayed bridges. Key Words: Dynamic Response Component, Pseudo-Static Response Component, Covariance Function, Stationary Response, Transient Response, Spectral Density Function, Spatially Varying Ground Motions, Filtered White Noise, Incoherence Effect, Wave-Passage Effect, Site-Response Effect, Cable-Stayed Bridge. VII