Study on the law of vertical evacuation behavior during earthquakes considering social relationship

Abstract

With the increasing density of people in buildings and complexity of building structures, pedestrians will inevitably be affected by social relationships during vertical evacuation when an earthquake occurs. However, empirical data on the evacuation of pedestrians on stairs in small groups are lacking in the current research. This study aims to analyze and discuss the impact of social relations between pedestrians on the evacuation efficiency and individual behavior after an earthquake. Field experiments were conducted in a university campus with 84 volunteers, and the variables considered were social relationships, speed, and obstacles. After tracking the pedestrian trajectory using the PeTrack software, the interpersonal angle and distance, average speed, time–space relationship, step frequency, offset angle, and pedestrian lateral oscillation were calculated and analyzed. The results show that pedestrian groups with close social relationships have smaller interpersonal angles and distances, and their speed of evacuation is faster than that of pedestrian groups with unfamiliar social relationships. A subjective increase in pedestrian speed increases the evacuation speed and step frequency, whereas road obstacles produce the opposite results. The findings of this study can provide basic data for modeling the vertical evacuation of pedestrian groups as well as a reference for studying the complex characteristics of pedestrian movement during earthquakes.