| Prestressed concrete continuous beam bridges have been widely used in various bridge constructions because of their many advantages,such as small deformation,beautiful linear shape,easy maintenance,smooth running,and good seismic performance.The construction method of continuous beam bridge is mostly cantilever cast-in-place.The construction period is long and the construction process is complicated.It will be affected by many factors.Therefore,it will have many adverse effects on the internal force and deformation of the main girder.In order to ensure that the main girder alignment meets the design and specification requirements,the internal force of the main girder after completion of the bridge is close to the design theoretical value,and to ensure the safe construction of the bridge,it is necessary to monitor the whole process of the bridge construction.Based on the summary and analysis of domestic and foreign scholars’ research,this paper takes the newly built Baihe Bridge in Xinye County as the background,combined with Midas civil finite element software,adopts the forward analysis method for structural analysis and calculation,and takes the calculation results as the theoretical basis for construction monitoring.The main analysis is as follows:(1)Combined with the construction design drawings,the Midas civil finite element calculation model of Baihe Bridge is established.The construction process of the main bridge is simulated and calculated,and the theoretical deflection values of the control points and the theoretical stress values of the cross-sections are calculated in each construction stage.And the theoretical values are statistically analyzed as the theoretical basis for construction control.(2)According to the measured deflection of the main girder on site,the least square method is used to identify the main design parameters to obtain their true values,and the calculation model is adjusted according to the recognition results to make the model as close as possible to the true state of the main girder.The gray prediction model of Baihe Bridge is established by using gray prediction theory to predict the deflection value of the main girder,forecast the pre-cast height of the main girder,and provide monitoring instructions.(3)The whole construction process of the main bridge of Baihe bridge is tracked and monitored.With the help of various measuring instruments,the deflection values of the control points and the stress values of the control interface in each construction stage of the bridge are collected,and the measured values are compared with the theoretical results,so as to fully grasp the linear change and safety condition of the bridge,and to ensure the reliability and safety of the structure in the construction process,the relative elevation deviation of the closure section is less than the allowable value of the specification,so that the main beam linear after the completion of the bridge can meet the requirements of the design specification.(4)By using ANSYS finite element program,the Junction-coupled finite element model of heat flow and heat structure are established to analyze the distribution of temperature field and stress field of hydration heat reaction of 0# mass concrete.The cooling plan of block 0# is analyzed and its rationality is analyzed to prevent the occurrence of temperature cracks in the box girder.Analyze the temperature field and stress field of the concrete around the cooling water pipe,and judge whether the concrete around the cooling water pipe will crack according to the analysis result of the stress field,so as to judge the rationality and feasibility of the cooling scheme.Analyze the temperature field and stress field of the concrete around the cooling water pipe,and judge whether the concrete around the cooling water pipe will crack according to the analysis result of the stress field,so as to judge the rationality and feasibility of the cooling scheme. |
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