Study On Damage Mechanism And Control Technology Of Simply Supported Structure Under Car-induced Vibration

The prefabricated structure is more and more widely used in bridge engineering,but a large number of engineering practice feedbacks show that compared with other bridge structure forms,the bridge deck paving defects of the simply supported multi-beam prefabricated superstructure are more prominent.Up to now,the mechanism of disease occurrence of this type of structure has been fully explored from the static point of view,but the bridge deck pavement and lateral connection diseases induced by vehicle-induced vibration still need in-depth research.To this end,this thesis is funded by the Henan Province Technology Project " Study on Damage Mechanism and Control Technology of Simply Supported Structure under Vehicle-Bridge Coupling Vibration "(No: 2020J-2-9),relying on the double-span G107 Shahe Bridge in Luohe City the actual engineering of the50 m simply supported main bridge,through theoretical and numerical analysis of the dynamic response of the fabricated simply supported T-beam bridge deck pavement under vehicle load,and combined with field measurements and laboratory impact fatigue model tests,carefully explored the pavement and The occurrence mechanism,influencing factors and effective control measures of horizontally linked diseases.The main work and conclusions of the thesis are as follows:1.Through the finite element ABAQUS software,on the basis of the dynamic response analysis of the pavement layer,the influence of vehicle speed,horizontal force and lateral connection failure on the force characteristics of the pavement layer is analyzed.The results show that the positive and negative alternating shear stress caused by the dynamic load is the main cause of the interlayer failure of the pavement.The peak shear stress increases significantly with the decrease of the vehicle speed and the increase of the horizontal force,and the existence of the transverse connection can be effectively reduced.With alternating stress amplitude,the probability of interlayer failure of the pavement layer is lower.2.Based on the on-site dynamic load test,a laboratory impact fatigue model test was carried out,and it was found that under the action of cyclic load,the interlayer shear strain of the pavement layer continued to increase,and the accumulation of fatigue damage continued to develop,especially the accumulation rate of shear strain along the bridge was significantly higher Shear strain in the transverse direction.When the transverse connection fails,the growth rate of the fatigue strain between layers increases significantly,and the probability of bridge-direction diseases on the pavement layer is higher.3.Based on the test results,the research on pavement disease control technology was carried out.In terms of the structure of the pavement layer,the size and layout of the transverse partition,specific measures to improve the stress state between the pavement layers are proposed to guide the actual project.