Analysis Of Regulatory Mechanism With Cable Force And Prestress Effect In Arch Section Stress Of Over-span Suspended Concrete Arch Bridge

It is especially important to control the upper and lower edge tension stress of the arch section of cantilever construction of reinforced concrete arch bridge.When the tensile stress exceeds the limit of the arch,it will cause the arch ring to crack.This is a great harm to the arch ring structure without prestressing force.There are many factors influencing the tensile stress level of the arch ring in the process of cantilever casting.Such as cable force value size,arch ring pouring segment length,temperature,reinforcement ratio,buckle tower height will affect the tensile stress in the arch ring cross section size,and with the increase of its span,the factors affecting the tensile stress level of the arch ring are also increased,and the force behavior of the section is more complicated.For example,the non-linear behavior of the buckle,the configuration of prestress,etc.,the sectional tension stress control will become increasingly difficult.In this paper,the stress and prestress are studied,and based on the national natural science foundation project background--Shatuo Super Large bridge is supported,the following research is carried out:(1)The stress balance method is the basic research idea,and the optimization theory is introduced.Taking the square sum of tensile stress on top and bottom slab of arch ring section in construction stage as objective function.The corresponding design variables and state variables are specified,The arch ring parametric model by ANSYS APDL is established.Based on the first order module of ANSYS,the cable forces could be optimized and adjusted in construction stage.(2)On the basis of the optimal and adjustment of cable forces,the prestress is arranged at the position of high tensile stress on the upper edge of the section to adjust and control the section stress in the process of arched ring cantilever casting.The local model of arch segment is established by large general finite element software ANSYS,the relative optimum scheme is determined by comparing calculation and analysis of different distribution positions and ways of reinforcement distribution.(3)The full bridge finite element model was established using the bridge special software Midas/Civil.The pre-stressing effect is simulated in the construction stage according to the determined bundle scheme,and compared to the stress results without prestressing,and the influence of prestress on the tensile stress of arch ring section is obtained.The results of comparative and analysis can provide a new way of thinking for the construction of duper large span cantilever concrete arch bridge,and have certain engineering significance.