Calculation Method And Experimental Study On Load Transverse Distribution Of In-service Assembled Beam Bridge

For the current situation of frequent bridge safety problems,how to make an accurate assessment of the safety performance of the existing bridge is an urgent problem to be solved.In the evaluation of in-service bridge before detection and reinforcement,the transverse distribution coefficient of bridge load is an important evaluation parameter to measure the transverse distribution ability of assembled bridge.However,when the in-service bridge is damaged,the traditional theory of calculating the transverse distribution coefficient is no longer applicable,and it is difficult to measure the transverse distribution coefficient of bridge load.Therefore,how to calculate the bridge accurately and quickly The transverse distribution of the actual load becomes an urgent problem to be solved.In addition,after the bridge is damaged,the transverse distribution of the actual load is also a problem worthy of study.In view of the above problems,this paper studies as follows:(1)Taking 12 assembled T-beams and small box girder bridges as the background,through the load test data of the real bridge,the measured conversion value of the load transverse distribution coefficient is obtained.At the same time,considering the three key factors of the vertical fundamental frequency,the linear stiffness and the width span ratio,a main beam stiffness damage reduction coefficient is introduced.The load considering the damage of the main beam of the bridge is obtained by the multiple nonlinear regression analysis method of MATLAB software The reliability of the formula is verified by an example.(2)Based on the hinged plate beam method,a simplified model is proposed for the damage of bridge girder and hinge joint.The damage degree is considered by the damage reduction coefficient of girder stiffness and hinge joint stiffness,which is taken as the parameter to be modified.Then,the static model modification technology is used to modify the modified parameter,and the load considering the damage of bridge girder and hinge joint is obtained The calculation method of transverse distribution is verified by an example.(3)Based on Bayes theory,the output parameters are transformed into a forward calculation.At the same time,the stochastic response surface model is used to replace the finite element model,and then a Markov chain is constructed by DRAM algorithm to avoid the ill condition of the posterior distribution.At the same time,the target function is constructed by the combined dynamic and static method,and the output parameters after the model modification are obtained,that is,the actual main beam,diaphragm beam and hinge joint elastic model Finally,the calculation method of the transverse distribution of the bridge load is obtained.(4)Taking an assembled T-beam bridge which has been in service for more than ten years as an example,the bridge appearance inspection,static load test,dynamic load test and single vehicle load test are carried out respectively,and the calculation results of the calculation methods in the second,third and fourth chapters are verified and compared with the measured values,and then the application scope of each method is proposed.