Nonlinear Analysis Of Static And Dynamic Mechanical Properties Of Long-span Road-Rail Cable-stayed Bridge

With the rapid development of the highway and railway, the large span bridge engineerings are gradually appeared. Compared with the suspension bridges, the cable-stayed bridge with the advantages of high rigidity, good wind resistance, relatively low cost, is one type of the main recommendations of long-span Railway bridge. With the increasing the span of the cable-stayed bridge, the geometric nonlinearity becomes more and more obvious. In the analysis of static and dynamic mechanical properties of large span road-rail cable-stayed bridge, it is necessary to consider the geometric nonlinearity of the structure. In the view of the above content, the following aspects were mainly studied in this paper.(1)The development situation of domestic and foreign road-rail cable-stayed bridge were investigated, and the analysis theory of cable-stayed bridge were summarized.(2)Relying on a large span road-rail cable-stayed bridge as the engineering background,the finite element theory and geometric nonlinear analysis theory ere summarized, which is the basis of the analysis of the large span road-rail cable-stayed bridge.(3)The finite element model of the road-rail cable-stayed bridge was established, with the reasonable cable force based on the matrix displacement method. The displacement and stress state of the bridge and the cable force were calculated and analysed, considering the cable sag effect and beam-column effect and large structure displacement effect. The large displacement effect had an obviously impact on the structural displacement calculation, then the cable sag effect, the effect of the beam column is most unobvious.(4)The static mechanical properties of the road-rail cable-stayed bridge in service stage were calculated and analysed, including the displacement and stress of the structure under the temperature effect, static wind effct, settlement of supports effect. By changing the parameters of the effect, the sensitivity of the static behavior of the structure on the temperature effect, static wind effct, settlement of supports effect was analysed.(5) The natural vibration characteristics of the road-rail cable-stayed bridge were calculated. And the influence on the natural vibration characteristics of the structure were calculated and analysed by changing the quality of the structure, the main truss height and width. On this basis, the displacement and stress of the structure were calculated under the response spectrum analysis and the time history analysis by changing the structural parameters. The influence of structural parameters on the structural seismic response was also calculated and analysed. The structure quality and the main truss height and the main truss width mainly influenced the displacement of the structure under earthquake,and no obvious effect were found on the structural stress.Conclusions were found by the study:The stress of the pylon of cable-stayed bridge showed an approximately symmetrical distribution under the reasonable finished dead state.The cable force was related to the cable length. The large displacement effect had an obviously impact on the structural displacement calculation, then the cable sag effect, the effect of the beam column is most unobvious.The influence of the geometry nonlinear on the cable stress was not obvious.The structure quality and the main truss height and the main truss width mainly influenced the displacement of the structure under earthquake,and no obvious effect were found on the structural stress.