EFFECTS ON NUMBER OF CABLES FOR MODAL ANALYSIS OF CABLE-STAYED BRIDGES

摘要

Due to the use of computer technique and the use of high strength material. The span lengths of cable-stayed bridges have been increased. Compared with continuous and suspension bridges, cable-stayed bridge deck has subjected to much stronger axial force caused by the horizontal component of cable reactions. The axial forces make the geometric nonlinearity for the bridges. Cable-stayed bridge is supported by cables instead of internal piers. Therefore, the pre-stress of the cable, inclined angle between the cable and the bridge's deck as well as the cross section areas of the cables are the most important features for this type of structure. With various number of cables, the cable-stayed bridges may have different prestress, inclined angles and the cable cross section areas. The stiffness of the bridge deck may be changed due to the axial forces. In this paper, the three dimensional finite element model of the bridge having the similar geometry with Quincy Bay view Bridge has been built. The modal analysis has been carried out by using different number of cables. The natural frequencies and their corresponding mode shapes are found and compared with those obtained from ambient test. The important effects on the number of cables have been drawn. The numerical results have been presented in tabular and graphical forms.