Study On The Importance Evaluation Of Key Nodes Of Urban Road Network Based On Seismic Vulnerability Of Bridges

As an important part of the urban road network,the bridge plays an extremely important role in maintaining daily work and life,transportation and emergency rescue,earthquake evacuation and social reconstruction after the earthquake.As the most vulnerable part of the road network,the seismic performance of the bridge determines the capacity of the road after the earthquake.The urban road network is the backbone of the city and the artery of the city.Whether the level is clear,the structure is reasonable,and the operational ability is reliable,is the key factor for the utilization of urban roads and the efficiency of urban operation.Therefore,the urban road network The structure has an important impact on the city's traffic.Moreover,the urban road network is a network with a wide distribution area,which is easily affected by natural disasters such as earthquakes,bad weather and floods,as well as traffic accidents,road maintenance and reinforcement.The failure of urban road network traffic function is often related to the destruction,congestion and interruption of key nodes in the road network.It can be seen that the key nodes in the road network play an important role in the security of the entire road network.Therefore,it is necessary to combine the seismic vulnerability of bridges and the topology of urban road networks to evaluate the importance of key nodes in the road network.The result of the assessment is that the urban road network management department should provide effective decision-making basis for traffic management control,road network maintenance and reinforcement,emergency rescue and evacuation.This paper relies on the national key research and development plan project "Research on the key technology of urban typical transportation infrastructure operation and maintenance safety"(2017YFC0806009)mainly to do the following work:(1)Summarizes the current research status of seismic vulnerability of key nodes and bridges at home and abroad,compares and analyzes the evaluation methods of key nodes in road network,and introduces the influence of vulnerability of key nodes on evaluation results.Combined with the operational flow of bridge seismic vulnerability analysis,the theoretical vulnerability and experience are clarified from the aspects of finite element modeling,ground motion intensity index selection,structural failure criterion,structural damage index and analysis and processing of analysis results.Analysis method of damage.(2)Considering the key role of bridges in urban road network and the research content of this paper,the definition of key nodes in the past is summarized,and the bridges in the road network are proposed as the key nodes in the road network.Compare and analyze the advantages and disadvantages of the original method and the dual method in the actual road network topology,and clearly use the dual method to the actual network abstract topology.Combined with the structural characteristics of dual topology,the evaluation indexes of key nodes are improved,and the node degree,intermediate center and near-centrality are determined as the evaluation indexes of key nodes in the road network topology.(3)According to the structural characteristics of the urban road network and the damage of the earthquake to the road network,the importance evaluation model of the key nodes of the urban road network based on the seismic vulnerability of the bridge is established.The gray correlation analysis method is used to consider the seismic vulnerability of bridges and the topological properties of key nodes in the road network.Through the specific examples,the theoretical vulnerability analysis and the empirical vulnerability analysis are described in the evaluation of the key nodes of the road network,and compared and analyzed.(4)According to the example of a specific urban road network,the key node importance evaluation model of urban road network based on bridge seismic vulnerability is established,and the importance of nodes in the road network is evaluated to verify the proposed basis.The practicability and reliability of the critical node evaluation method for road network seismic vulnerability.