Modelling and finding optimal evacuation strategy for tall buildings

Abstract

The construction of many tall buildings has brought increased interest in building regulations for timely evacuation. The 9/11 terrorist attacks and the recent fire event in Glenfell Tower in London raise concerns about the effectiveness of evacuation strategies of tall buildings. Thus, a method for finding an optimal evacuation strategy for tall buildings was proposed enabling people to use the available egress components in an optimal way. The introduced method took into consideration the stochastic nature of people’s behaviour, modelling the randomness in decisions of people, and the capacities of egress components. The considered building evacuation procedure required using stairs, evacuation lifts, and refuge floors, where a state-of-the-art evacuation process was modelled. The results indicated that the problem should be considered as multi-objective taking into account the total evacuation time, and the number of people waiting on their floors to start the evacuation in the building. As a case study, a 56-story building with 5400 people was tested, which resulted in a complete evacuation within the period of one hour. Also, the equations for modelling the pre-movement time of people for office buildings were identified enabling the calculation of discharge rate of people during evacuations in tall buildings. The explained modelling approach and subsequent analyses are useful for building designers and should be utilised to examine evacuation design performance of any tall building.