Construction Control Of Span Continuous Rigid-Frame Bridge And Error Analysis

Along with the development of bridge construction and the improvement of prestressed technology, long-span pre-stressed concrete continuous rigid frame get more and more applications. To ensure the line of built bridges matching with the expectation and the safety of bridges in construction, the construction control is paid more and more attention. This paper is based on the construction of Taihe Ganjiang bridge of the Ji'an expressway of Beijing-Guangzhou main line, create the model with MIDAS/CIVIL software,give the elevation of shuttering and the theoretical value of key sections stress of the whole bridge to guide the construction.At the same time,the sensitivity of key parameters of construction are analyzed.According to the analysis of parameters,we can find the basis for adjusting the parameters. Calculations suggest that,concrete density, shrinkage and creep of concrete have great influence on the deflection and tress of structure.So, concrete density error and shrinkage and creep must be precisely considered in construction control. Elastic modulus of concrete is inversely proportional to the structural deflection.Elastic modulus of concrete have great effect on the structural deflection and little effect on structural stress.Under the completion of bridge, local temperature difference on the structural have great effect on deformation and stress, in particular,there is large deflection in the largest cross-section cantilever.So, it is important to measure the temperature of beam when setting the shuttering. Deflection observation must be strictly arranged in the early morning between 6:00-8:00.Annual range of temperature have great effect on the structural deflection and little effect on structural stress. Channel coefficient of friction and deviation factor of pre-stressed plastic bellow have little effect both on the structural deflection and stress.Use the Grey theory into the construction control of Taihe bridge and write the command stream of with MATLAB software to adjust the camber. After closure of the bridge.the error of closure section is less than 12mm.the deviation between theory and accumulative total of each section is less than 15mm which is full content with expectation.This shows that.using Grey theory in construction control of long-span prestressed concrete continuous rigid frame can optimize the camber and guide the construction.