Construction Simulation Analysis And Parameter Sensitivity Study Of Large-span Highway-rail Suspension Bridge

As a bridge type that simultaneously satisfies two modes of transportation,the public-rail dual-use suspension bridge is becoming more and more dominant in the construction of suspension bridges.The public-rail dual-use suspension bridge has a large main cable diameter,a large stiffening beam,a large dead load concentration,and a second-stage dead load.Due to its high proportion,its construction method is different from that of highway suspension bridges.This article takes Wufengshan Yangtze River Bridge as the background and analyzes the different construction methods and influencing parameters for the two important links of main cable and stiffener construction in the suspension bridge construction,mainly including the following:(1)According to the design parameters of the Wufengshan Yangtze River Bridge,the MIDAS / Civil finite element software was used to establish the suspension bridge model,and the cable shape was calculated using the nodal method and the segmented catenary method,respectively,and compared with the design line shape,which verified the finite element software Calculation accuracy and model accuracy.(2)The construction process of the three stiffening beam connection methods of the articulated method,the rigid connection method and the rigid-hinge combination method is simulated,and the displacement and internal force changes of the main cable and the stiffening beam during the construction of the three connection methods are compared.The rigid-hinge joint method is superior to the rigid-joint construction scheme,and the rigid-hinge joint scheme is revised according to the internal force of the temporary joint and the change of the lower chord opening to ensure the rationality of the hinge position.(3)The two stiffening beam erection sequences from mid-span to pylon and from pylon to mid-span were simulated,the effects of the two erection sequences on the main cable and the stiffener beam alignment were compared,and the stiffener beam alignment change and stiffener beam construction were discussed The relationship between the internal force and the impact of the stiffener beam shape and internal force changes on the rigid joint construction of the front stiffener beam are analyzed.The analysis shows that the construction of the span-to-center tower has a better opportunity to facilitate the rigid joint of the stiffener beam,and the internal force of the stiffener beam is more It is small and can reduce the number of jacking constructions at the same time.It is recommended to use the mid-span bridge tower construction scheme.(4)By comparing the construction parameters such as the elastic modulus of the material,temperature difference,construction load and the second-stage constant load loading method,the sensitivity of the displacement and internal force changes of the main tower,the main cable,the stiffening beam during construction to the different construction parameters is analyzed,and the main cable The shape of the bridge with the stiffening beam is less affected by the parameter changes.The shape of the empty cable has a higher sensitivity to changes in elastic modulus,temperature and load.The temperature change has an important influence on the shape and internal force of the overall structure of the bridge.The construction stress during loading is relatively large,and it is recommended to adopt the method of preferentially unidirectional or synchronous laying of the second-stage railway load from both sides.The research results provide references for the construction work of the main cable frame of Wufengshan Yangtze River Bridge,the construction of the stiffening beam frame,the push-up construction of the cable saddle,and the construction of the second-phase constant load paving.