The mechanism of hindering occupants’ evacuation from seismic responses of building

Pedestrian evacuation from buildings during an earthquake needs to consider human behavior and building shaking. This study sets up an indoor evacuation model based on the social force and dynamic mechanics. First, social forces were formulated in the Eulerian coordinate system, seismic force that excites on pedestrians in a multi-story building is derived from structural acceleration, and an evacuation criterion is given based on above forces. Second, a simulation was performed through VB programming, which accounts for the situation that people evacuate from a walkway. Parameters of the social force model are modified in order to estimate pedestrians’ acceleration in concerned situation. Third, structural dynamic responses under a series of ground motion excitations with varying peak values are acquired through finite element analysis to determine pedestrians’ seismic forces. Then, pedestrians’ ability to escape safely is evaluated according to evacuation criterion. Results show that seismic force would increase when pedestrian located on higher floor or ground excitation is of more dramatic level. Additionally, the possibility of survival is likely minimized as long as seismic force is larger than social force. This proposed model is capable of describing the effects of environment on human behavior during earthquake evacuation.