Evacuation simulation of multi-story buildings during earthquakes based on improved cellular automata model

Abstract

s The evacuation process in buildings provides an efficient method for engineers to evaluate the rationality of the architectural design and structural design scheme. The simulation of the authentic evacuation process is conducive to accurately evaluate the casualties of buildings under earthquake. The economic loss estimation in the performance-based seismic design method can then be implemented. This study improves the traditional cellular automata model in order to simulate the crowd evacuation process in buildings under earthquake. The modified model simulates the attraction of exits to crowds, herd behavior of crowds, avoidance behavior for obstacles, decision-making behavior for paths/exits selection, and conflict between pedestrians in the evacuation process. Based on the variation coefficient of evacuation time and video which records authentic evacuation under earthquake, the influence coefficients of each factors are determined. In addition, the modified cellular automata model uses the refined cellular space to describe the geometric dimensions of the evacuation environments and obstacles, and therefore it improves the accuracy of the evacuation model. The explicit finite element method is used to simulate the seismic damage process of structural and non-structural components. The judgment criterion of casualties which combines the finite element model with the evacuation model, is proposed. The number and distribution of casualties are predicted based on the criteria. The prediction method for casualties helps the architects to optimize the size and layout of the building components. In the structural design stage, identifying areas with high population density or high casualties is conducive to optimize the structural design scheme, and provide a basis for the formulation of a post-earthquake rescue plan. Finally, a seven-story official building with reinforced concrete frame structure located in Dujiangyan City, Sichuan Province, China is considered as example to verify the rationality and applicability of the proposed method.