Research On Evacuation Strategy In Commercial Building Based On Optimal Traffic Flow System

An important research question is how to evacuate people from commercial buildings as quickly as possible after a sudden event.The existing research is either focused on evacuation path planning in buildings with the goal of the shortest evacuation time and shortest evacuation path,which is difficult to meet the flow requirements for path selection.Or the study of the evacuation of people between urban areas based on traffic flow theory with system optimization as the goal and user optimization as the goal,which is difficult to meet the need for evacuation of people inside buildings.Or the study of the evacuation of people within buildings based on traffic flow theory with user optimization as the goal,which is difficult to meet the need for the shortest total time for evacuation of all people.We also construct a static model for evacuating people in commercial buildings based on the optimal traffic flow system and a dynamic model for evacuating people in commercial buildings based on the optimal traffic flow system,design algorithms to solve the models separately;and give examples for verification and strategy comparison.The main work and innovative results of the paper are as follows.Optimal evacuation strategy for people in commercial buildings based on static traffic flow system.Based on the optimal theory of traffic flow system,the generalized evacuation time function is defined,the shortest total generalized evacuation time for all personnel in the commercial building is the objective,and for the characteristics that the internal structure of the commercial building cannot be changed instantaneously during the evacuation of personnel,the capacity constraint of the road section is added to establish the optimization model,and the uniqueness of the model solution is proved.The problem is solved by designing a Frank Wolfe algorithm with nested generalized Lagrange multipliers.Finally,the static system-optimal evacuation strategy for commercial buildings takes less time and is more suitable for evacuating people in commercial buildings than the static user-balanced evacuation strategy for commercial buildings.Optimal evacuation strategies for people in commercial buildings based on dynamic traffic flow systems.Considering that the evacuation flow of people,in reality,is dyna mic and gradually loaded,the evacuation flow of people on the road section is set as a time-varying state variable,introducing time-varying inflow rate and outflow rate of ev acuation flow of people on the road section,taking the inflow rate of evacuation flow of people on the road section as the control variable,and considering the situation of e vacuation flow of people generated at an intermediate node at a certain time.Based on the optimal theory of traffic flow system,the shortest total evacuation time for all the people in the commercial building is the goal,and to avoid the evacuation flow of people on the road section at any moment exceeds the capacity limit,the capacity constraint of the road section is added,the FIFO constraint is added,and the function of the outflow rate of the road section is derived to establish the optimization model.The optimality conditions of the model are analyzed by constructing Hamilton’s function and Lagrange’s function,and the necessity and sufficiency of the target problem are derived by derivation.The results show that the optimal evacuation strategy based on the dynamic traffic flow system has a shorter total evacuation time for all personnel and is more suitable for the evacuation of personnel in commercial buildings.The research achievements of this paper can provide a new theoretical basis for the evacuation of people in commercial buildings after the occurrence of sudden events.A reference for managers to develop evacuation plans for people in commercial buildings.