Space Stress Analysis Of Long Span Continuous Beam Bridge In Cantilever Construction

The long-span prestressed concrete continuous beam bridge is a widely used bridge form in these days due to its superior structural system. Taking the overall security factors of long-span prestressed concrete continuous girder bridge into account, spatial stress analysis of Chong He Bridge is needed because the internal force change of bridge structure is complex in the period of construction. A very important process of prestressed concrete continuous beam bridge is the pier beam consolidation in cantilever pouring construction. Zero block and one block are relative complex part of in bridge construction process while two block is the starting point of cantilever pouring construction, which have great realistic meaning on research work of stress analysis and detection. Therefore, a comprehensive stress analysis is essential, which provides important basis for construction monitoring work and plays a positive role in promoting the safe construction of the whole bridge.With Chong He Bridge as engineering background, problems to be considered and processing methods are introduced using Midas Civil software to establish bridge model. Meanwhile, the bridge finite element model is set up.Normal stress is checked in various construction phases and is compared with measured values to verify the correctness of model; The space finite element model of zero block, one block and two block in different construction phrases are set up by Midas FEA. Simulation of the unit selection, meshing and boundary conditions and loads are introduced in detail. The calculation results comparison of3D entity model and the ones of plane linkage are quite close, which shows that the establishment of three-dimensional entity model is correct. Stress spatial analysis is made to zero block, one block and two block in the construction phase of the initial cantilever, maximum cantilever, side-span closure and mid-span closure. The normal stress value, longitudinal positive stress, the position and stress distribution are obtained, which provide guarantee for the construction quality control; Analysis of the hydration heat of zero block and one block of concrete pouring process is made, which shows that the maximum principal tensile stress of concrete pouring is1.33MPa. Cracks may occur in section of great principal tensile stress. Therefore, necessary measures of monitoring and construction control should be taken to reduce the influence of concrete hydration heat on zero block and one block. Through contrastive analysis of measured value and theoretical calculated values of the15#pier top root section,1/4section of main span and middle span section stress, it can be concluded that measured value and theoretical calculated values shows similar development trend with numerical simulation results, which shows that the conducted analysis can provide guarantee for the project construction quality control.