Study On Static And Dynamic Load Test Of Long Span PC Beam Bridge

Long span PC continuous girder bridge is one of the most commonly used bridges in our country,the main characteristics of the long span PC continuous beam bridge are the low deformation rate,small expansion rate and smooth running,which makes the bridge expansion joint set less,which is good for high speed driving.According to the requirements of highway maintenance technical specification issued by the Ministry of communications of China,the bearing capacity of long-span bridges must be evaluated.Due to the current theoretical calculation and the actual situation of the bridge there is a certain gap,so the carrying capacity of the identification can not be separated from the load test.At present,there exists the problem of vehicle bridge coupling vibration in both the existing bridge and the new bridge,on the one hand,the vehicle driving on the bridge deck will have a dynamic impact on the bridge structure,which makes the vibration of the bridge structure affect the normal operation of the bridge,on the other hand,the vibration of the bridge structure,in turn,affects the vehicle,which makes the stability and comfort of the vehicle affected,it is necessary to carry out the load test of the bridge.Bridge load test is the most direct and effective means to evaluate the quality of bridge.The bridge load test can not only verify the rationality of theoretical calculation,but also promote the development of theoretical calculation and test theory.In this paper,the static and dynamic load test of long span PC continuous beam bridge is studied,taking Dongfeng Bridge as the research object.Under the static and dynamic load tests,the strain and deflection of the bridge are studied.Large scale finite element software MIDAS/Civil is used to model the Dongfeng Bridge,input cross-section data,boundary conditions and load values.Research on static load test of bridge,the internal force of the control section under the design load and test load is calculated respectively,coefficient of load efficiency;under different conditions,the measured values of strain and deflection are compared with the measured values.Study on the dynamic load test of bridge,modal analysis of Dongfeng Bridge Model,subspace iteration method is used to calculate eigenvalues,the first order vibration modes of the bridge are obtained,the natural frequency is obtained,according to the corresponding standard,the impact number is calculated,the values obtained from modal analysis are compared with those obtained by field test equipment,such as the test data of the sports car and the jumping car,and compared with the corresponding bridge design standard,the allowable value of the load test standard;the deformation and dynamic characteristics of bridge structures under static and dynamic loads are normal,the overall stiffness of the bridge is good,bearing capacity to meet the design requirements,further verify the rationality of the design,it provides reference for carrying capacity analysis of similar bridges,it also provides valuable information for future bridge maintenance,repair and operation health monitoring system.