Study On The Mechanical Properties Of Wide Span Asymmetric Cable-stayed Bridge

Since the beginning of the 21 st century,with the rapid development of economy and society,the number of vehicles in China has been increasing.The ordinary three-lane and four-lane roads have been unable to meet people's travel needs.More and more wide-span Bridges have been built.Based on the monitoring project of no.1 bridge of Haidong avenue,Haidong city,this paper studies the mechanical properties of wide and large span asymmetric cable-stayed Bridges.Based on the basic principle of the grillage method,the spatial grillage model of the whole bridge is established by MIDAS / civil.Further calculation and analysis of the static performance of the bridge in the construction stage and the static performance in the operation stage,comparative analysis of the impact of two different construction methods on the mechanical performance of the cable-stayed bridge;Qinghai area belongs to the area with large temperature difference,considering the obvious temperature effect of the bridge structure in the area with large temperature difference,analysis of the impact of the temperature load on the stress of the cable-stayed bridge after the completion of the bridge;finally,using the finite element software MIDAS/FEA establishes the spatial finite element model of the main girder cable beam anchorage zone,calculates and analyzes the stress distribution of the anchor box under the maximum cable force,analyzes the thickness of the bearing plate and shear plate of the anchor box,and studies the influence of the thickness change on the overall stress of the anchor box.In this paper,the static mechanical properties of the wide and long-span asymmetric cable-stayed bridge are studied.The calculation and analysis show that: during the construction process,the stress and deformation of the cable-stayed bridge meet the requirements of the code,the changed construction method has a great impact on the initial tension construction cable force of the cable-stayed bridge,has little impact on the deformation and stress of the main beam and the main tower,and the actual construction method of the bridge is safe and feasible;in operation The transverse bending of the main girder and the uneven distribution of stress along the cross section under the action of vehicle symmetrical load and unbalanced load at the stage are in line with the obvious transverse spatial effect of the wide cable-stayed bridge,so it is not accurate to use only single beam model for checking calculation in design;the temperature load has a great influence on the main girder line shape,main tower deflection and cable force of the cable-stayed bridge,and it is selected in summer or continuous in closure The period with high temperature in a few days is favorable for operation;the overall rise and fall temperature has the greatest impact on the longitudinal displacement of the support,and the most unfavorable temperature load combination affecting the longitudinal displacement of the support of this type of cable-stayedbridge is: negative temperature difference of cable beam + positive temperature gradient +overall temperature drop + positive temperature difference between left and right of cable tower;under the dead load + most unfavorable live load condition,the stress of the main beam cable beam anchorage zone meets the strength requirements,and the overall stress level The thickness of bearing plate can be increased properly under the condition of convenient welding,and the thickness of shear plate should not be too thick.The research results of this paper can provide theoretical basis for the determination and construction of the reasonable completion state of this kind of cable-stayed bridge.