Journal of Materials and Engineering Structures
Volume 7, Numéro 1, Pages 113-124
2020-03-30

Sensitivity Study Of Load-dependent Ritz Vectors On Modal And Seismic Responses Of Cable Stayed Bridges

Authors : Ouanani M. . Tiliouine B. . Belkheri N. .

Abstract

In the present article, 3D Finite Element Model (FEM) of a bridge structure under load dynamics is performed in order to assess the sensitivity study of Load-Dependant Ritz vectors (LDR) on modal and seismic responses of cable stayed bridges. In this context, two techniques are examined in the present study for solving structural dynamics problems; the Traditional Modal Superposition (TMS) technique and that of Load-Dependent Ritz orthogonal vectors (LDR). The latter is based on a very efficient algorithm allowing the systematic generation of Load-Dependent Ritz orthogonal vectors (LDR), the accuracy of this method is significantly influenced by the selection of LDR vectors used for the modeling of the structural behavior. The cable-stayed bridge connecting two districts in eastern Algeria, characterized by an expected Peak Ground Acceleration (PGA) equal to 0.275g in accordance with Algerian seismic design code is selected in order to perform critical modal properties such as, frequencies, shapes of the required vibration modes and effective mass participation as well as the dynamic response of the cable stayed bridge under earthquake loadings in three orthogonal directions (longitudinal, transversal and vertical). The results of this study reveal that the LDR vectors method which has the important advantages of short Central Processing Unit (CPU) time as compared to traditional modal method is very efficient for modal and seismic analyses of cable stayed bridges.

Keywords

Cable-stayed bridge; 3D FEM; Modal superposition; Ritz Vectors; Modal and seismic analyses