Simulation Calculation Research On The Typical Construction Stage Of The Superstructure Of The Second Changshou Yangtze River Bridge In Chongqing

The construction of Chongqing Changshou Yangtze River Second Bridge went through typical construction stages such as main tower pouring,cable erection,and steel box girder main girder hoisting.During the pouring of the double-column multi-layer inwardly inclined bridge tower,the temporary active cross bracing plan was optimized under the guarantee of the line shape and stress of the main tower to meet the requirements,saving costs and reducing construction period;Chongqing Changshou Yangtze River Second Bridge spans both banks of the Yangtze River,on-site The measurement and control site is far away from the main span.When the main cable erection measurement is performed,the best measurement station for the control network should be selected reasonably,and the erection measurement results should be corrected to improve the erection accuracy of the main cable.Finally,when the main girder is hoisted,Chongqing The steel box girder hoisting of Changshou Yangtze River Second Bridge adopts a relatively rare asymmetric hoisting process.During the construction process,the vertical displacement change law of the main cable and the lifting point is different from symmetric hoisting.It is necessary to simulate the typical construction stage of the main girder hoisting process.simulation.This article takes the Chongqing Changshou Yangtze River Second Bridge as the engineering background.The main work completed and the results obtained are as follows:(1)The design optimization scheme of the temporary active transverse bracing of the main tower of Chongqing Changshou Second Bridge was proposed,and the Midas civil finite element software was constructed to establish the finite element model of the bridge tower.The structural deflection and internal force of the bridge tower at each construction stage were calculated.Combined with the monitoring data,the results show that after the temporary active cross bracing is installed,the deformation and internal force changes of the main tower are reasonable,meet the design requirements,and have sufficient safety reserves to meet the safety requirements in the construction of the bridge tower.(2)Based on the law of error propagation,the error calculation formula in the theory of the triangular elevation one-way observation method is deduced,and the optimal station selection method for the cable strand measurement theory in the construction control network of the Chongqing Changshou Yangtze River Second Bridge is proposed.The measurement results of the erection of the reference strands were corrected through the maximum error value of the actual measurement at each station,which provided theoretical support for the high-precision erection of the cable strands of the bridge.(3)The Midas civil finite element software was used to establish a calculation model for the lifting construction phase of the Chongqing Changshou Yangtze River Second Bridge,and the geometric parameters of the asymmetric suspension structure of the steel box girder were analyzed.And in the actual construction process,combined with finite element software for monitoring and tracking of key parameters,it provides a theoretical reference target value for the construction control of asymmetric hoisting of steel box girder.(4)Through ANSYS Workbench finite element simulation software,the entity model of the lower hanging point area was established,and the force analysis of the hanging point structure at the short rod was carried out,and the theoretical prediction value of the offset of some short rod was obtained,which guided the on-site inspection.A simple assessment of the safety of the bridge during the construction process was also carried out.