Impact Coefficient Analysis Of Continuous Rigid Frame Bridge Based On Unevenness Of Bridge Deck

With the rapid growth of national economy and the continuous progress of science and technology,the demand of highway and bridge transportation increases rapidly.In the present highway traffic system,the traffic density is increasing,the speed of vehicles is increasing and the load of vehicles is increasing,so it is very necessary to analyze and study the impact coefficient of continuous rigid frame Bridges.There are many factors that affect the impact coefficient of the bridge,including:natural vibration frequency of vehicles,damping ratio,number of vehicle axle and other dynamic characteristics of vehicle load,structural vibration mode,natural frequency and damping coefficient and other structural dynamic characteristics of the bridge,deck unevenness and speed,etc.Considering the above factors,the condition of bridge deck is one of the most important factors affecting the impact effect of vehicles on the bridge.Therefore,based on the measured bridge deck not flatness and trigonometric series method,simulation of bridge deck flatness,based on the use of research and development of car-bridge coupled vibration analysis based on Matlab software,respectively,considering the different speed and different Bridges in the damping,the continuous rigid frame bridge under different vehicle weight across different across different neutralization on the left of the vibration response and impact factor analysis.The research in this paper is part of the research content funded by the natural science foundation of hunan province(2019JJ40313).The main research contents of this paper are as follows:(1)establish 1/4,1/2 and 3d vehicle models,and mainly derive the vibration differential equation of 3d vehicle model.(2)bridge deck irregularity samples are simulated by trigonometric series method,and the measured bridge deck irregularity data of two groups of different bridge conditions are sorted out.The motion equation of vehicle-bridge coupling system is established and solved by newmark-beta method.(3)based on the different values and calculation methods of the impact coefficient in China and other countries,the main factors affecting the impact coefficient are bridge span,structural fundamental frequency,bridge type,number of lanes and vehicle load type,etc.Different countries have different emphasis on the impact factors of the impact coefficient,and the calculation results are not the same.(4)taking a large-span continuous rigid frame bridge as an engineering example,the influence of bridge deck irregularity,vehicle speed,bridge damping and vehicle weight on bridge dynamic response is analyzed.Based on the analysis of the impact coefficient of rigid frane Bridges under the measured and simulated bridge deck irregularity,it is concluded that the calculated value of the impact coefficient of Bridges varies greatly when considering the different bridge deck irregularity,and the calculated value of the impact coefficient is compared with the standard value of various countries.