The Research On The Torsional Properties Of Wide Concrete Cable-stayed Bridge With Central Cable-plane

Wide concrete cable-stayed bridge with central cable-plane has beautiful shape,Good mechanical performance,wide driving field and other advantages,it will be more and more favored by contemporary designers.With the development of society,the volume of traffic is growing,the possibility of eccentric load is getting higher and higher,It is well known that the wider the cross-section of the bridge,the greater the torque on the structure under the partial load,and the cable in the form of the central can hardly provide effective torsional rigidity.If the main beam is insufficient in torsional resistance,The construction and operation will have a great threat to security,so the study is necessary.Based on a typical wide concrete cable-stayed bridge with central cable-plane bridge,this paper uses ANSYS analysis software to establish the finite element model,analyzes the torsional performance on the construction and the finished state of the bridge.According to the characteristics of the bridge,the box girder,the diaphragm and the location of the auxiliary pier will be analyzed in-depth.The details are as follows:(1)Introduce the development of wide concrete cable-stayed bridge with central cable-plane,summarizes the contributions of the predecessors.Based on the characteristics of the projects,the paper list the contents.(2)The torsional behavior of the bridge is analyzed,the results show that the overall torsional performance of the bridge is strong,mainly as follows: the maximum vertical displacement caused by the eccentric load is 1.31 times under the symmetrical load,The stress distribution of the beam is reasonable,although the torsional distortion stress is produced,but the value is small,which does not affect the overall force characteristics of the bridge.(3)The torsional behavior of the maximum single cantilever and the maximum cantilever state is analyzed by the five key indexes of vertical displacement,torsion angle,reaction force,tower deviation and stress generated from the load.The results show that the maximum double cantilever state In the construction phase is weak,the maximum displacement of the section under the eccentric distribution of the temporary load is 1.68 times of that under the symmetrical distributed load,which exceeds the accuracy of the jointing and has a great influence on the subsequent construction of the bridge.Under the eccentric load,The support force on the side of the cantilever state is about 1.1 times of that under the symmetrical load,and the maximum single cantilever state is 1.06 times.With the decrease of the distance from the cross section to the tower beam,the stress value is increasing and the distortion effect Continue to decline.(4)In order to analyze the influence of different number of box chambers on the torsional behavior of the whole bridge,three key indexes of vertical displacement,torsion angle and countercurrent force are compared and analyzed.The results show that,to some extent,with the increase of the box,the vertical displacement of the same cross section tends to be similar,the twist angle tends to be the same,and the reaction force decreases.(5)In order to analyze the influence of the spacing of the diaphragm on the torsional resistance of the whole bridge,three key indexes of vertical displacement,supporting force and stress are analyzed and compared.The results show that with the spacing of the diaphragm smaller,the vertical displacement and the reaction force are larger and the stress is relatively improved.Through the comparative analysis of the vertical displacement,the supporting force and the tower deviation,it is concluded that the change of the longitudinal position of the auxiliary pier has no obvious effect on the constraint full bridge torsion.