Continuous Bridge Cantilever Construction Process Monitoring And Analysis Of Partial Stress Of Zero Blocks

Prestressed concrete continuous beam bridge is a kind of bridge which is relatively commonly used in project. It has a simple,fluent shape and can be build easily. DaShaPing continuous beam bridge is a prestressed concrete continuous box girder bridge which is (64 +112 +64) m span, constructed by diamond basket cantilever construction method.It is im-portant for understanding the stress situation about 0 block of the concrete continuous beam bridge to understand the make a stress analysis.This paper describes the linear control and stress monitoring methods and content, and the zero block of the local stress field, mainly to complete the following:(1)Firstly, the situation of prestressed concrete continuous beam bridge and the devel-opment of construction control technique,as well as the contents of the construction monitor-ing are presented.(2)Secondly, through the finite element program MIDAS/Civil to establish a whole bridge model about DaShaPing continuous beam bridge, in the simulation analysis, the weight of beam, prestress,bridge loads, shrinkage and creep of concrete structural system and changes in conversion and boundary conditions are considered. Through analysis and calcula-tion, the results of continuous bridge girder section at various construction stages and key cross-section elevation of the stress changes are given.(3)In the linear monitoring part,the linear monitoring flow and the form work erection elevation are introduced, and several comparison charts of change in beam deflection in key stages are listed. In the part of stress monitoring,the testing principle and the apparatus are presented, and several comparison charts of change in beam stress in key stages are listed.(4)Finally, the analysis of partial stress in the box girder blocks zero of DaShaPing con-tinuous beam bridge is completed by ANSYS program, and the discussion about the location of cracks in 0 block and the appropriate measures are taken.The transverse and vertical ten-dons are considered in the 0 block solid model, simulating the roof of the zero block web and bottom of the chamfered part in the model detailedly. Model concrete and prestressed tendons separately, and then using the constraint equations connect both of two.Extract displacement from MIDAS/Civil results to be the loads on the model.It is analyzed that the stress of the zero block of roof, floor, web and diaphragm stress.It can be concluded from the study as follows:(1)It should be taken a construction monitoring for long span prestressed concrete con-tinuous beam bridge which is build by cantilever construction method.(2) According to the monitoring in the linear and the final closure results of the DaShaP-ing continuous beam bridge, the use of MIDAS/Civil finite element analysis procedures of the monitoring work plays a correct guiding role in the construction, the testing principle and the instruments used in the stress test meet the requirements in construction process.(3)It can be concluded from the analysis results about the 0 block in DaShaPing con-tinuous beam bridge, that the strength of 0 block concrete is in the range of tensile strength and compressive strength,when 0 block is in the situation of maximum cantilever.It illustrates that setting prestress tendons can modify the situation of stress in the 0 block which is com-plex.(4)It can be known from the whole monitoring process about DaShaPing continuous beam bridge that not only the full realization of intelligent control in long span bridge con-struction issues should be studied further but also the protection in the sensor is worthy to be studied.