Analysis Of Removing Temporary Supports For Prestressed Trough Girder Of High-speed Railway

This paper is about research of the sequence selection of removing temporary support in the construction of a high-speed railway prestressed concrete though girder.There are many uncertain factors in the construction site,such as complex construction environment,half construction control measures,improper management,can not achieve the objective of removing temporary support synchronously.This paper analyzes the stress situation of the trough girder because of the possible occurrence of removing temporary support non-synchronous,and put out a reasonable solution.The main jobs are as follows:(1)In this paper,I discusses the common construction methods of trough continuous girder bridges,and discusses the problem of the construction of the trough continuous girder bridge.(2)Analyzed the problems that may arise during the removing temporary support of trough girder bridge.Through the analysis,the stress situation of the grooved beam and the condition of the structural safety of the grooved girders were obtained by means of longitudinal bridge and transverse bridge.(3)The finite element model of the process analysis is built by Midas Civil.According to along bridge and transverse bridge directions,8 defferent working conditions are given.The trough girder bridge is simulated by beam-shell combined element,the temporary support is simulated by compression only spring,the process of removing temporary support is simulated by activate and deactivate of compression only spring.(4)Analyzed the rationality of different sequence of removing temporary support,and put out a most suitable removing sequence.Proposed several matters needing attention.According to the calculation data and analysis,there are the following conclusions:(1)The whole bridge across each in accordance with the uniform deflection ratio carride out to the most advantageous,stress of the channel beam but when construction environment do not allow the midspan carride out first,both sides across the subsequent carride out carride out solutions to the optimal choice at the same time.(2)The non-synchronous removing of the longitudinal bridge will not cause the main tensile stress of the beam to exceed the standard.However,when the middle span is removed,and the other two spans is not removed,the tensile stress in the bottom will be too big.This condition should be avoided in construction.(3)To the trough girder,whose bottom is wide,transverse uneven removing will make the trough girder slab by the large tensile stress,so the horizontal synchronous removing ways must be taken.