Research On Influence Of Vehicle-Bridge Coupling Vibration On Expansion Joint Of Concrete Beam Bridge And Control Countermeasures

The rapid economic growth has led to a sharp increase in the volume of highway traffic in China,which has led to the need for widening and rebuilding of a large number of expressways,involving numerous existing bridge widening and reconstruction projects.Due to the unfavorable factors such as vehicle vibration,uneven settlement and shrinkage and creep during construction and operation of the new and old structure joints of the widening bridge,various types of damages are easily caused.Therefore,reasonable measures are taken to reduce and control the adverse effects of various factors on the long-term performance of the new and old bridge joints,and to avoid the occurrence of various diseases in the construction and operation of cast-in-place concrete joints.It is the key technology for the new and old bridge widening project.The research on the adverse effects and control problems of vehicle dynamics on cast-in-place joints is not deep enough.Based on the numerical analysis method of vehicle-bridge coupled vibration,the dynamic behavior characteristics and reasonable construction scheme of cast-in-situ joints under traffic load are studied.Systematic analysis and research have been carried out with the selection of traffic control schemes.Firstly,relying on the existing research results,the structural vibration deformation and vibration velocity indicators of the influence of vehicle dynamics on cast-in-place joints are proposed.Taking a widening project of 30 m prestressed concrete simply supported T-beam bridge for the reconstruction and expansion of the Laiwu-Linyi section of the Beijing-Shanghai Expressway,the self-programmed vehicle-bridge coupled vibration analysis program is adopted to consider the bridge deck condition,vehicle speed and vehicle.The effects of lateral position and joint concrete ageing factors,etc.,systematically analyzed the dynamic behavior characteristics and laws of the widened bridge joints under the action of vehicle dynamics.Secondly,based on the numerical analysis method of various typical heavy-duty vehicle loads in China's highways,considering the influence of various factors such as vehicle type,vehicle speed,bridge deck condition and vehicle position,the system carried out statistical analysis of the dynamic behavior characteristics of bridge joints.The probability distribution model of impact coefficient and vibration velocity was obtained by K-S test method.Based on the 95% confidence level of the joint dynamic effect data,the statistical analysis of the displacement impact coefficient and vibration velocity is carried out,and the regression coefficient of the impact coefficient and vibration velocity of the common prefabricated concrete beam bridge is established.Provide a basis for impact assessment.Finally,the four common technical measures to reduce the adverse effects of traffic loads on the joints are analyzed,and the effectiveness,applicability and economy of each measure are analyzed.The research proposes a comprehensive control method for the adverse effects of vehicle vibration combined with traffic control and segmental pouring.Based on the results of statistical analysi s and regression formulas for widening the impact coefficient and vibration velocity of the bridge under the above-mentioned typical heavy vehicle,relying on the construction process of a 30 m prestressed concrete simply supported T-beam bridge joint joint,the traffic control and pouring construction scheme design The validity and applicability of the proposed method are verified.