Study On Construction Control Of Long Span Prestressed Concrete Continuous Rigid Frame Bridge Based On Grey Theory

Continuous rigid frame bridges are widely used because of the consolidation of pier and girder,the main pier without bearings,the bending stiffness of the bridge along the main direction,the torsional rigidity of the transverse bridge,the ability to span,and the mature construction technology.The construction techniques of this bridge include cantilever pouring,cantilever erection and rotary construction,among which cantilever casting method is the most widely used;A large number of existing bridges statistics found that the continuous rigid frame bridge in the process of using the cross deflection amount is larger,and the web is prone to crack,and the cantilever casting process for pouring girder section of pouring beam will produce cumulative deflection effect,so the construction process using scientific and reasonable theory to treat pouring beam end state the prediction is very necessary,the grey theory can better achieve the purpose.In this paper,based on the project of five Tuojiang bridge,by using the grey theory prediction method for long-span cantilever construction of continuous rigid frame bridge were analyzed by Midas Civil finite element model was established.The model includes forward and backward two types,by simulating the actual construction process of the bridge,the internal force and deformation,the stress analysis of the bridge,and then guide the bridge construction control,research results are as follows:(1)Through the finite element modeling analysis,the ideal stress and deflection of the bridge during the construction process are obtained.In this paper,based on the Tuojiang five bridge,using Midas Civil to build the finite element model established respectively according to the formal bridge model with backward method,check calculation and design,analysis and calculation of stress and deflection of bridge construction.(2)Then through the analysis of the construction state of the prediction stage,the bridge construction scheme is optimized by comparing the open loop,closed loop and grey theory predictive control methods.Based on the grey theory,the state of each section in the cantilever construction process is analyzed and predicted,and the pre camber of bridge construction,the pre installation of bearing installation and the jacking and pushing plan are optimized.(3)Then,the application of Grey Theory in bridge monitoring is expounded and proved by comparing the theory with the measured data.The Tuojiang River five bridge monitoring data and theoretical values are compared.The results show that the bridge construction to fold prediction and linear test data and theoretical approaches,grey theory can better serve the needs of monitoring of continuous rigid frame bridge,and the backward simulation analysis method and formal method used can accomplish the initial the state and construction process.(4)Finally,the load test proves that the bridge performance meets the application requirements.The bridge load test theoretical values are compared with the measured values.The results show that the bridge has enough stiffness and strength meet the design load level(Highway-grade)use requirements,the high degree of coincidence with the theoretical value and actual value.