Post-earthquake Transportation Emergency Based On Vulnerability Analysis

Transportation networks are the most important lifeline system when earthquake and other natural disasters happen. Recent earthquakes in the world have demonstrated the importance as well as the vulnerability of transportation networks. After the occurrence of an earthquake, a transportation network plays a crucial role in all the evacuation related activities. However, at the same time, the vulnerability of the transportaion network usually hinders the emergency traffic organization after earthquake. In the emergency traffic organization after earthquake, network reconstruction and rescue path routing are fundamental problems and both constrained by the vulnerability of transportation networks. So based on vulnerability analysis of transportation networks to solve the network reconstruction and rescue path routing problem could not only provide dicision rules for emergency traffic organization after earthquake but also improve the speed of emergency response. To understand network vulnerability level and identification the key units, which can provides basis for strategic decision, and influences the transportation emergency response speed. By constructing new vulnerability index to represent transportation functional loss consequences, and then establishing post-earthquake network restore order optimization model and the optimal rescue path routing model, and the algorithm. The main contents are as follows:Analyzed and summarized the vulnerability definitions in various disciplines, and defined transportation vulnerability as abnormal events caused transportation netwrok physical damage and functional loss consequences, as well the consequences susceptive analysis. Considering post-earthquake traveler's route choice behavior plays an important role in transportation network performance loss consequences analysis. This paper has given two new vulnerability indexes:the first is integrated accessibility index, which is integrating three factors (the gravity measure of accessibility and topology importance and node inherent). The other is transportation network efficiency index, which is defined as OD/shortest path cost. And then gives the application process.While analysis post-earthquake vulnerability influence factors, traffic demand analysis and network physical performance are the key factors to quantize transportation network vulnerability. On analysis of traffic demand uncertainty, traveler's path choice behavior is described as:traveler is unable to reduce the expected trip cost by changing his path choice probabilities while the evil entity is unable to increase the expected trip cost by changing the scenario probabilities, without cooperating. This paper adopts the Nash mixed strategy model getting the road flow which was constructed by Bell.When the destructive earthquake happened, effective transportation emergency measures are the only way to decrease losses. Post-earthquake road reconstruction not only considers the numbers of tools and teams constraints, but also time urgency, and then constructing transportation network repairing bi-level programming model which based on vulnerability analysis with the transportation network vulnerability minimize, and giving algorithm. Another key problem of emergency is the rescue path routing, with the path to disaster area which has safety and transportation efficiency and vulnerability maximize, constructing path routing multi-objective programming model and solving.Based on the vulnerability theory exploration and methodology designing, are applied to Northridge earthquake abstract network. Through the base date gathering, get the post-earthquake damaged sections repair arrangement and the optimal rescue path.