Study On Impact Of Bridge Forced Deceleration Belt On Simply-Supported Girder Bridge

Bending-slope-bridges are common in mountain roads due to topographical conditions.In order to control the driving speed and ensure traffic safety,the forced deceleration belt is set up on the bridge surface,and the impact effect of the vehicle when passing through the forced deceleration zone will increase the power response of the bridge.Domestic problems have occurred due to the setting of forced deceleration caused by the cracking of beams,endangering the safety of bridges and driving.However,at present,there is little research on the impact of the mandatory deceleration belt on the bridge impact at home and abroad,and there are no relevant provisions on the design of the bridge forced deceleration zone in the current design specifications.Simply-supported girder bridge is the most widely used bridge in mountain roads,for this reason,this paper for a 40 m simply-supported T-beam bridge,to carry out a mandatory deceleration zone on the impact of the bridge impact study,the main research content is as follows:(1)In view of the difficulty of using analytical expression of the impact load when the vehicle passes through the forced deceleration belt,and the problem of calculating the high cost of calculating the impact of the forced deceleration belt parameters on the simple girder bridge with fine model,this paper puts forward the method of extracting the contact force between the tire surface and the forced deceleration belt from the LSDYNA software,and then using the method of rectangular impact load simulation bridge forced deceleration belt,and using this simulation method based on ABACQUS software to compile the user sub-program to establish the vehicle-bridge-force deceleration belt simplified model.(2)In order to verify the accuracy of the simplified simulation method of the forced deceleration belt,the simplified model based on ABAQUS and the fine model of the carbridge-forced deceleration belt are established with LS-DYNA software to compare and analyze the dynamic deflection and dynamic stress of the simple girder bridge.(3)To carry out the impact analysis of the forced deceleration belt on the impact of the simple branch beam bridge,based on the spectrum analysis of the dynamic deflection,the paper puts forward the high frequency vibration coefficient to assist in assessing the impact of the bridge by the power load shock,and combines the bridge impact coefficient to analyze the impact of the forced deceleration belt on the simple branch beam bridge.(4)In view of the problem that the vehicle causes the bridge to vibrate violently through the forced deceleration belt,the numerical simulation method is used to analyze the effect of the forced deceleration belt position,height and spacing on the dynamic deflection of the simple branch beam bridge from both the time domain and the frequency domain,and the results of the parameter analysis give the optimization scheme of the forced deceleration belt to reduce the impact on the simple branch beam bridge.