Research On The Key Technology In Construction Control Of Long Multi-span PC Continuous Beam Bride

During the segmental construction of the multi-span continuous beam bridges, the system transforms and removing the temporary consolidation will lead to the change of the internal force and deformation of the structure as the main beam extends.In order to ensure not only the joining accuracy of the structural and the alignment of the finished bridge, but also the final elevation meeting the design requirement after a period of operation,it is very important to execute process control in long-span prestressed concrete continuous girder bridge.Based on the project of the Hanjiang Bridge, the paper analyses and studies some factors which make affect linear and stess of the bridge, Through establishing beam-element models using the program Midas/Civil, combining with the practice of construction control, the thesis makes the simulation analysis about the whole construction processes. The paper mainly has the content and conclusion as follows:1. The paper calculates stress of multi-span continuous beam under cantilever stage which is in accord with the measured value, verifying the validity of the model,and calculates accumulate displacement in three years of bridge completed,and provide the theoretical basis for formwork layout.2. System conversion has little impact on the structure, and shrinkage and creep of concrete has greater impact, especially on vertical displacement by studying inflence of the structure system conversion and shrinkage and creep of concrete on the deflection and stress of the continuous box girders.3. The thesis analyze the factors that affect the stress test, and the testing data modified is in accord with the theoretical value.4. Sunshine temperature difference exerts great influence on the displacement and stess of the cantilever beam, and experimental and theoretical calculations show that, the longer the length of main girder, the greater the deformation caused by sunshine temperature difference, and the roof on the surface generate the large horizontal tensile stress and longitudinal compressive stress with the rising of temperature. So, the influence of temperature must be taken into consideration in construction control.And the paper introduces a method fot the rectification of elevation of framework erection. 5. The temperature difference hardly affect the linear after the bridge is built, but the long association of Long Multi-span Bridge which is caused by the change of the bulk temperature, is quite remarkable, the biggest reaches 16.8cm,so more attention should be paid to extendable device.6. The paper analyze that three different types of closure order affect internal force of multi-span continuous beam bridge,and we can get the optimum closure plan only from internal force.