Study On Process Optimization Analysis And Construction Control Of Single Inclined Tower Mixed Beam Cable-stayed Bridge

With the development of science and technology,modern bridge construction has put forward higher requirements for its structural stress,use function and bridge-based beauty.The single inclined tower mixed beam cable-stayed bridge possess excellent mechanical properties and unique appearance.It has become a new type of cablestayed bridge structure.During the construction process,due to the cumbersome,the geometric nonlinear effect and the difference material of the main beam,the construction controll is difficult.In order to ensure the bridge state meets the design requirements.This article is based on a single inclined tower mixed beam cablestayed bridge in the mountain area of Hubei as the engineering background.The paper mainly carries out the full bridge construction process optimization,slope without stress length analysis,mixed beam line control and structural parameter sensitivity analysis,the following conclusions:(1)Based on the objective conditions of the temporary vertical support groundbased load insufficient and optimize the main tower construction process stress,the finite element software Midas civil was used to carry out process optimization analysis and main tower temporary support pushing.The results show that: by sacrificing a small part of the safety of the bridge,tense two pairs of main span cables,reduce temporary vertical jacking force,adjust the timing of temporary support and accurately pushing temporary vertical measures are adopted.It can ensure the smooth progress of the construction.By using formal method to simulate temporary support jacking force and real-time stress monitoring methods,which can ensure construction process of the stress of the main tower is safe.(2)Explanation of an unstressed length Buffton Ruffssen Iterative Algorithm based on a suspension line theory,which fully considers the coupling of single cable force and cable-horizontal angle.It iteratively solves the key feature parameter of the suspension line equation,compare its calculation results with Ernst equivalent elastic modulus and existing suspension line method calculation results.This method has the characteristics of fast convergence,high precision and simple calculation,which is convenient for actual engineering applications.(3)Based on the full support method of the side-span concrete beam and the cantilever assembly method of the master span steel box girder construction characteristics.The main beam installation line can be iterately calculated by the zero initial displacement method.The steel box girder manufacturing line can be calculated by the tangent initial displacement method.At the same time need to compute the unstressed angle,top-bottom plate length and length correction amount.The manufacturing line and installing line of concrete beam is alike,through linear superposition designed elevation,the bridge pre-arch and the construction pre-arch have completed the actual linear error controlled within the 1cm.(4)In order to explore the structural behavioral characteristics and laws of the construction process of the single inclined tower mixed beam cable-stayed bridge,after determining critical structural parameters and structural response indicators.The analysis of single factor sensitivity with a single variable control method as the core and the analysis of multi-factor sensitivity with orthogonal test design as the core were carried out.Through the entire process monitoring the main beam prefabricating,bridge crane installation,and accurately identify of the most sensitive factors level combination(the weight of the main beam-8% change,the bridge crane-25 T change,the elastic modulus of the cable 6% change,the stiffness of the main tower 8%change),which can effectively ensure the reasonable bridge state.