| With the rapid advancement of urban bridge construction,the prefabricated design and construction of bridges has entered a high-quality development stage,showing the advantages of high efficiency and less pollution.For bridge safety,the installation of barriers is the most effective measure to ensure the safety of bridges.However,the connection between fabricated components has also become the core issue in the design and construction process of fabricated barriers.The vertical connectors between the prefabricated concrete barrier and the bridge deck and the longitudinal connectors between the standard sections are directly related to the safety of the barrier under the impact of the vehicle.This study takes the prefabricated barrier on the steel-concrete composite beam bridge in the first fully prefabricated urban bridge project in Guangzhou — — the Fangcun Avenue South Fast Reconstruction Project as engineering background,research has been carried out on the optimization design of bridge prefabricated barrier connectors.The main work is as follows:(1)A finite element model of the 1.5t car-barrier collision system was established,and the reliability of the established finite element model of the collision system was verified from indicators such as energy conservation during the collision,force of frontal impact on rigid walls,frontal impact displacement and side impact damage.The verification results show that the established dynamic finite element model is stable and reliable;(2)Aiming at the optimization problem of vertical connectors,a two-stage optimization design method based on dynamic topology optimization and Kriging matamodel is proposed:In the conceptual design stage,the hybrid cellular automaton algorithm is used to optimize the dynamic topology of the connectors,and the optimal distribution of materials in the design domain is determined;In the parameter design stage,the genetic algorithm is used to establish the parameters of the Kriging metamodel,which realizes the application of the Kriging matamodel in optimizing the size of the connector.The two-stage optimization design method was applied to the optimization design of the vertical connection of the relying engineering,and the inverted T shape with the optimal size was obtained,which verified the effectiveness of the proposed method;(3)Crash FE simulation is used to obtain the dynamic response of the longitudinal connector under the impact of vehicle collision.Then,through the static FEM based on ABAQUS,the model is loaded to failure to study the failure mechanism and mechanical properties of the connector.The proposed parameter optimization method is adopted to optimizes the parameters of the back steel plate longtitude connector,which have betterperformance under the impact of vehicle collision;(4)The optimized design scheme is comprehensively evaluated in terms of connection performance,cushioning performance,anti-overturning performance and safety performance.The results show that the optimized barrier system of the connector meets the requirements of the safety evaluation index in all aspects. |
