Study On Construction Control Of Long-Span Prestressed Concrete Continuous Beam Bridge

As the national economy develops,the demand on the transportation of people is improved constantly.Bridge engineering,one of the important part of transportation,achieves a greater construction scale.And the prestressed continuous girder bridges has become one of the preferred bridge types for bridge construction because of its advantages of small deformation,large rigidity and easy maintenance.Long-span prestressed continuous girder bridges are applied in the construction of long-span bridges gradually following the increased span of the bridge,Howerever,the construction of long-span prestressed continuous girder bridge is complex and difficult,especially in typhoon-prone areas.So the wind-resistant safety performance should be considered in the process of bridge construction except meeting the structural alignment and stress requirements.Importantly,the monitoring of long-span prestressed continuous girder bridge should be valued in the construction process.Based on the engineering background of a 13-span continuous prestressed concrete beam bridge(40.55m+11×64m+40.55m),this paper establishes the finite element model of a real bridge to evaluate the whole construction process and analyze the data from construction monitoring.And the contents of this study are as follows:(1)Sensitivity analysis of design parameters of long-span prestressed continuous girder bridge in construction process was carried out.The influence rule of the change of corresponding parameters on stress and alignment of bridge structure is obtained through calculation.The main influencing parameters of bridge in maximum cantilever state and completed state were determined alonging with sensitivity function,which can guide and apply to construction monitoring process.(2)A perfect construction control system wasestablished to monitor the alignment and stress of the bridge in the construction process.The bridge structure can meet the design requirements in tthe whole construction process by comparing the theoretical and measured values of alignment and stress in the cantilever construction,closure and completion stages.(3)The grey GM(1,1)model included with grey system theory was established to predict and control the deflection error in the construction process.Further,the reasonable prediction method suitable for long-span prestressed continuous girder bridge was determined thriugh analyzing the prediction accuracy of different prediction methods,which provides a reference for similar projects.(4)Through CFD fluid calculation module in Midas/FEA software,the mechanical behavior of long-span prestressed continuous girder bridge in typhoon-prone area under wind load was simulated and analyzed.The variation rule of aerodynamic coefficients of bridge section under different wind attack angles was studied,and the deflection of structure under different wind velocities was calculated.Therefore the wind-resistant safety performance of long-connected prestressed continuous girder bridge during construction was determined.Finally,the influence of wind load and construction load combination on bridge structure under maximum double cantilever state was analyzed.