Research And Application Of Multi-span Rigid Frame-Continuous Composite Girder Bridge Construction Control Technology

Multi-span Rigid frame-continuous composite girder bridge is a complex of statically indeterminate structure,the main pier use pier beam consolidation while set seats at side pier. In the course of construction controling the linear structure and internal force to reach the ideal state of structural shape and internal force. At this stage,multi-span rigid frame-continuous composite girder bridge usually uses hanging basket cantilever construction method,which needs a longer construction period. There are some deviations in the parameters of the structure between the theory value the actual value, such as the structural design parameters, temperature load, concrete shrinkage and creep effect, closure sequence etc. While in the course of construction, pier top in a row set pier-beam temporary consolidation, structure conversion as the construction is completed. Under the influence of these factors produce deviation between actual and theory calculated linear dimensions internal force.In the course of construction,if not analysis the reasons for deviation and not take appropriate measures in the next box-girder construction, deviations rapidly accumulates with the new segmental box girder construction, it also increases construction security risks,until it causes quality and safety accident.Therefore,establish the construction control system of multi-span rigid frame-continuous composite girder bridge is necessary in the actual construction process, collects the parameters that affecting the structure actual state,comparative analysis the actual theoretical calculation parameters,then correct the theoretical calculation model, theoretical calculation model can accurately reflect the actual state to guide the actual construction process better, Ultimate theory of structural shape and inner force to meet state requirements.This paper bases on Xiyang River bridge project in the Shan Xi province. First, the sensitivity of design parameters in the rigid frame-continuous composite girder bridge are analyzed, including concrete density, elastic modulus and loss of pre-stress value. Introducing the concept of sensitivity coefficients identify the main design parameters during the largest cantilever state and the finished bridge. It can conclude that the down-warping of main girder is growing rapidly as a bridge for 5 years, the full-bridge integral down-warp but each span is slightly different for 10 years, through analyze the effect of concrete shrinkage and creep effect. Then analyze the structural stress and displacement state through the temperature load affect, and put forward the measure to control temperature load effect. In the end, analyze the actual displacement and stress state in the different closure sequence, and determine the reasonable closed project.On the basis of the above analysis, present the construction monitoring scheme of Zhunxing Yellow River bridge, including monitoring contents, methods, system, etc. Comparating analyze the structural linear and stress data between the measured and theoretical analysis results, the conclusion is given finally.