Research On Load Lateral Distribution Of Simply Supported Small Box Girder Bridge Based On Model Test

With the progress of science and technology,the improvement of economic and cultural level,the development of urban construction,the grade of road and bridge design is gradually improved,and the requirements for driving comfort are also higher and higher.From the force performance analysis,the biggest advantage of small box girder bridge is that it has large torsional capacity,and its torsional inertia moment is about ten times or even tens of times of the corresponding T beam.From the appearance,the small box girder has a lower building height.From the economic point of view,the thin-walled structure of box girder and the single span of bridge deck decrease,which reduces the bridge's self-weight.The material consumption is relatively less than the same span hollow slab bridge,and the price is cheaper.Therefore,in the construction of bridges in recent years,the use of small box girder bridges has become more widespread.In this paper,a practical simple-supported small box girder bridge is taken as an example,and a simple-supported small box girder bridge test model is made according to the scale of 1:10.The results of the model test are analyzed,and the variation law of load lateral distribution is studied.On this basis,according to the force characteristics of simple-supported small box girder bridge,the lateral load distribution of simple-supported small box girder bridge is numerically calculated and analyzed by means of space finite element analysis software,and its influence on the lateral load distribution is analyzed by changing the loading position.Finally,the method of rigid-jointed beam and hinge-jointed beam are selected to calculate the lateral load distribution,and the correction method for the errors is proposed.The main work of this paper is as follows:(1)By consulting literature,the development,characteristics and research status of simply-supported small box girder bridges are summarized.Based on the theory of load lateral distribution calculation,the calculation method and applicability of load lateral distribution coefficient of simple supported small box girder bridge are summarized.(2)According to the size of a real bridge and the scale of 1:10 model,by using 5251 aluminium alloy is used to fabricate the test model of simple-supported small box girder bridge.Loading tests of the model in different load cases are carried out.According to the model test results,the lateral load distribution law of simple-supported small box girder bridge in different loads is analyzed and discussed.(3)Taking a simple-supported small box girder project with a span of 20m as an example,the plate element and solid element models of small box girder bridge are established by finite element method.The deflection and stress values of each main beam are calculated in different load cases.The results of numerical simulation and traditional rigid joint beam method,hinge j oint beam method and model test are analyzed to explore the reasonable method for calculating lateral load distribution of simply supported small box girder bridges.(4)The relative error between the results of hinge joint beam method and model test is smaller than that of rigid joint beam method and model test,and the results of rigid joint beam method are smaller.For simple-supported small box girder bridges without inner diaphragms,if the rigid j oint beam method is used to calculate the lateral load distribution,it is suggested that the amplify 1.045 modification coefficient for vertical value of influence line,and if the lateral distribution of load is calculated by the hinge joint beam method,it is suggested that the amplify 1.033 modification coefficient for vertical value of influence line.