| The geometric nonlinearity,concrete shrinkage and creep,temperature and other influences during the construction of the dense cable system of the cable-stayed bridge make the location of the bridge closely related to the construction process.However,most of the current cable force optimization methods based on one-time bridge calculation cannot be accurately accounted for The above-mentioned effects related to time,process,etc.,based on the actual construction process,there is always a deviation between the final completed state of the cable-stayed bridge and the reasonable completed state.Based on the engineering background of a prestressed concrete cable-stayed bridge with a span of 150m+328m+150m,this paper uses large-scale finite element software to study the determination of the reasonable construction status and construction control of the cable-stayed bridge.The specific research content includes:(1)This paper introduces the method of combining the main beam force balance method based on the influence matrix with the rigid support continuous beam method,determines the reasonable cable force of the bridge,and constructs the long beam according to the principle of the influence matrix.The influence matrix equation of long-span cable-stayed bridge with cantilevered cable car is derived.considering the four cable force influencing factors of the newly-tensioned stayed cable,the weight of the newly cast beam,In view of the temporary load in construction and the forward movement of the hanging basket,the large-scale finite element software is used to solve the cable force influence vector,in MATLAB The above-mentioned influence matrix equation is solved,and on the basis of linear adjustment value,the modified influence matrix method that can consider the nonlinear effect is derived,and it is applied to the calculation of the reasonable construction cable force of a cable-stayed bridge.The comparison of the results shows that the use of the nonlinear modified influence matrix method can significantly reduce the calculation error of the construction cable force of the long-span cable-stayed bridge.(2)Based on the optimal alignment,the cable-stayed bridge’s cable force at the closing stage is optimized and analyzed,and the response surface method is introduced to correct the main girder line shape at the maximum cantilever end before the side span closing,and the three parameters of main girder bulk density,cable force and counterweight are adjusted.Recognize and correct the linear deviation by adjusting the parameters.The results show that the finite element linear correction based on the response surface can significantly improve the correction efficiency and accuracy of the model.As a method of bridge construction control to reduce the linear error,it has significant actual construction Monitoring and guiding significance.(3)Based on the safety considerations of cable-stayed bridge design,the optimal construction cable force is applied to the background project to calculate and analyze the construction phase and the bridge operation phase,and compared with the measured data of construction monitoring.The calculation results of each construction stage show that all calculation data meet the requirements of the specification,and have sufficient safety reserve margin.Under the action of standard load combination and short-term load combination in the bridge completion and operation stage,the results show that the analysis results meet the requirements of the code,and verify the feasibility of the nonlinear modified influence matrix method to calculate the construction cable force. |
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