Analysis Of Key Problems In Construction Of Multi-curved Arch Tower Of Unsymmetrical Single-pylon Cable-stayed Bridge

Relying on Shaoguan Qujiang Avenue Shaozhou Bridge this paper studies some key issues of the multi-curved arch tower which is a special-shaped tower in the construction and completion stages of the single tower unequal span cable-stayed bridge with asymmetric hybrid girder.Firstly this paper introduces the development of cable-stayed bridge and cablestayed tower introduces the mechanical characteristics of common cable-stayed tower and the structural forms of tower anchorage zone.Then through the analysis of the general engineering situation of the bridge and its pylon as well as the current research situation at home and abroad,it is pointed out that the key issues of the pylon in the construction stage are the scheme design of active lateral bracing during the climbing formwork construction stage,the mechanical behavior of the pylon and the mechanical performance analysis of the superelevation support during the cast-in-place closure stage.According to the research on the mechanical behavior of the active braces and the pylon during construction stage,this paper uses the large finite element software Midas/Civil to establish a calculation model of the pylon during construction stage.Through detailed analysis of the construction stage,this paper verifies the applicability of the design principle of braces on this pylon,designs and verifies the location and horizontal thrust scheme of braces,and obtains the mechanical behavior of multi-camber arch pylon in the construction stage.Aiming at the safety of the super-high closure support,this paper uses Midas/Civil software to calculate the mechanical properties of the support,and analyzes its stability considering the initial defects of the support structure.At last,the mechanical performance of the anchorage zone of the bridge tower is analyzed.Firstly,the calculation model of the bridge in the finished state is established by Midas/Civil software,and the reasonable cable force of the completed bridge is determined by the cable force adjustment method based on load balance method,and the most unfavorable position of the anchorage zone in the operation stage and the cable force at this position are found.Finally,the finite element model of anchorage zone is established by Midas/FEA software.The results show that the U-shaped prestressed tendons have good effect and sufficient stress reserve,but the structure should be strengthened at anchor holes and concrete teeth to prevent local damage caused by stress concentration.