Study On Evacuation Characteristics And Evacuation Strategy In Typical Regions Of Buildings

The development of high-rise buildings and public places such as theaters, stadiums and meeting halls suffers a rapid grow due to the fast increasing population. However, if emergencies such as fires carried out, it is very dangerous to escape from such kind of enclosures in which a huge crowd gathers. Therefore, how to evacuate pedestrians safely, effectively as well as fast becomes a very hot research topic in recent years. Furthermore, the issues concerning evacuation from room with obstacles and vertical evacuation in high-rise buildings are especially significant due to their structure characteristics.In this thesis, the characteristics and strategy for evacuation from typical regions such as multi-obstacle rooms, staircase and elevators in high-rise buildings were focused. The behavior characteristics, evacuation time and the pedestrian flow characteristics during evacuation were studied in detail. It is hopeful to provide suggestions and technical support for the optimal design of building structure and crowd management in evacuations.In the multi-obstacle rooms such as classrooms, theaters, conference halls and stadiums and other rooms with many ordered seats, the internal layout is clearly significant impact to the evacuation efficiency. Therefore, a series of evacuation experiments in a teaching building considering initial occupant distribution, the long-range sound information and special groups were conducted, and the evacuation routes were consisted of classroom, passageway and staircases. The analysis was focused on the route of individual evacuation and the correlation among exit choices. The results found that, there was a strong positive correlation between intermediate exit choice and final exit choice with the correlation coefficient was0.936. When the evacuation destination was uncertain, the choice of final exit was affected by the selection of intermediate exit, while the destination was certain, the final exit would control the selection of intermediate exit. In addition, there was a bifurcation point for the flow in the same row, which deviated from the exit side.A proposed model considering the aisle factor for multi-obstacle room could reproduce well the evacuation experiments, for example, the experimental result of the exit selective equalizer coefficient was22.6%while the simulation result was20.4%. The simulations also found that, the congestion usually occurred at the intersection of the horizontal aisle and the vertical aisle, not near the exit. In addition, the design such as the exits facing the aisle, the exits located at the corner of the side wall, and the aisle close to the wall with exits, were conducive to the evacuation. When the capacity was certain, it should be given the priority to the design of the aisle layout, rather than the seat layout.In the thesis, a model was proposed to simulate the pedestrian flow on stairs based on lattice gas model, in which the turning behavior on the staircase landing and the merging flow at the staircase entrance were considered in detail. The proposed model could reproduce the accumulation effect well and was used to analyze the pedestrian flow on stairs. In addition, the calculation methods of stairs evacuation time as well as elevator evacuation time were discussed. The results found that the evacuation time using stairs increased more quickly for the small-scale evacuation from low-level floors with the increasing building floor, while the evacuation time using elevators increased more quickly for the large-scale evacuation from high-level floors with the increasing building floor and evacuation size.Finally, based on the Bayesian analysis, a three-stage framework model for dynamic management of escape crowd during the vertical evacuation of high-rise buildings in case of fire was developed, in which the decision concerning evacuation scale, evacuation destination and evacuation modes in different stages were made by considering the fire development and the degree of risk in different regions. In addition, a framework concerning the information exchange between the managers and the evacuees was built based on evacuation indicator system, in which the managers release decision-making information, and the evacuees received the instructions and gave feedback evacuation information for the decision-making at the next stage.