The Analysis Of Key Problems On Incremental Launching Construction Of Prestressed Concrete Continuous Beam Bridge Across The Railway Line

Prestressed concrete continuous beam bridge occupied an indispensable position in bridge construction because of its better structural rigidity, less expansion joints, little deformation, maintenance easily, more affordable and so on.The bridge construction process is subject to topography, transportation lines and other conditions, while jacking construction method is widely used in bridge construction with the advantages that economy, the small necessary required equipment, small space occupied.The paper based on the prestressed concrete continuous beam bridge across the railway line by launching construction as the research object, studied simulation analysis of launching construction, carrying capacity of main piers and temporary piers, steel launching nose test and the construction monitoring in the process of incremental launching around the engineering background-Beijing-guangzhou over line linked of xiang fu Rd Xiangjiang River Bridge. The main works are as follows:(1) Selected the pier moving while beam does not move model form by contrastive analysis between the beam moving while pier does not move model and the pier moving while beam does not move model which are the two basic forms of continuous beam bridge incremental launching construction. Making simulation analysis of incremental launching construction of the bridge the whole process through the Midas/Civil software, then aimed at the worst-case on main piers in incremental launching construction to checking carrying capacity, and review again after reinforcement measures have taken. The results obtained meet the requirements.(2) It can get the most unfavorable conditions of the maximum moment in connection between launching nose and main beam during the incremental launching construction by establishing simulation analysis model of incremental launching construction of the bridge the whole process and finally determine the steel launching nose test scheme. Then establish the solid model of linked which appeared cracks in the connection between launching nose and main beam during the steel launching nose test, to analyze the structural stress under the most unfavorable conditions in theincremental launching construction, and to investigate the steel launching nose test importance and correlation analysis. The model results in keeping with the problems in field conduct, it calculated and got that there are large tensile stress on the cracks position, namely the bottom of web at the connection between main beam and launching nose.(3) Combining with lateral offset, stress, deflection and crack and other aspects monitors of incremental launching process’s construction monitoring on engineering project to analysis, it can offer reliable experience of construction monitoring on incremental launching to other bridges.