| Continuous rigid frame bridge is a kind of composite architecture,which has the superiorities of small deformation,high driving comfort,reasonable internal force distribution and strong crossing ability.It has been widely utilized for bridge structure and has become one of the most representative bridge types.However,the research on Vehicle-bridge coupling vibration is still very few.Therefore,it is very essential to study the vibration response caused by vehicle action,and the analysis of its dynamic response has been paid more attention by bridge field.In this paper,the Jiya Waterway Bridge in Zhongshan City was taken as the research object.The coupled model of vehicle-rigid frame bridge was built,and the MATLAB program was compiled based on the modal synthesis method and Newmark-β algorithm.The vibration responses of bridges with different pier types and different pier heights are solved.At the same time,the effect of vehicle weight,vehicle type and vehicle speed on the impact coefficient of the bridge is analyzed and expounded.The main works and results are as follows:(1)A simulation model of bridge based on ANSYS software was realized,and the vehicle model was considered as a spatial analysis model with 9 degrees of freedom.According to the model of vehicle and bridge,the coupled vibration equation was deduced,and the coupling vibration equation was solved by MATLAB software.(2)The vibration responses of the bridge under different types of piers were compared and analyzed.including thin-walled hollow piers,double-thin-walled hollow piers and four-column piers.The effects of vehicle speed,uniform and accelerated vehicle speed,and the number of crosswise vehicles on the vibration response of the mid-span and pier-top of the bridge are considered.The effect of pier type on the vibration response of bridge is obvious,and the difference of vibration response of bridge with different pier type is large.The displacement response and bending moment response of the bridge with double thin-walled piers are the minimum,while the displacement of thin-walled hollow piers is the smallest and the bending moment of four-column piers is the largest.Compared with the dynamic response of other bridge pier types,the displacement and bending moment of the bridge with double thin-walled piers are reduced by 67% and 100%.(3)The vibration response of the bridge was studied under different pier heights.The effect of some parameters on the vibration response of the bridge was studied,such as vehicle speed,vehicle weight,vehicle type,vehicle type and vehicle spacing,etc.The results show that the amplitude of vibration response for the bridge with high pier is obviously larger than that of the bridge with low pier under the effect of the above factors,which indicates that the vibration response of the bridge with high pier is more easily affected by the above factors.(4)The impact coefficient of bridge under the vehicle load was studied and the effect of some parameters on the impact coefficient of bridge was researched.The results indicate that the impact coefficient of the mid-span deflection for the bridge can still exceed the specified value in the code under some vehicle driving conditions,such as high speed driving,low grade bridge deck driving,partial load driving,etc.It is suggested that the specified value in the code can be adjusted appropriately.In addition,the impact coefficient of the bending moment of the bridge is obviously larger than the impact coefficient of the bridge displacement,the impact effect of the bending moment is not negligible,and the impact coefficient for the bridge should be considered when considering the impact coefficient. |
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