Experimental And Modeling Studies On Pedestrian Evacuation In Building Stairwell

With the fast development of global economics,more and more people spring into the bigger cities.Recently,fire becomes one of the disasters in high-rise buildings,and fire in high-rise building not only results in the loss of people’s property,but also caused a great number of casualties,which have raised a great sense of analysis in egress of high-rise buildings.The topic that occupant evacuate out of the buildings to arrive at safe zone is one of the popular ways to make sure safety of people in buildings.Thus it is of great significance to investigate the human performance in stairwell.Freely moving experiments were carried out when participants were exposed to 100%,12%and 0%ground illumination by wearing different glasses.It is found when stairs are divided into two components equally,pedestrians have a preference for inner side stairs.Furthermore,mean distance kept away from handrails with 0%illumination is the smallest at the same section,compared to 12%and 100%illumination conditions.However,when stairs are divided into three parts equally.some phenomena are observed and some conclusions could be drawn and shown in the following:1)under 100%and 12%illumination both females and males have a preference for middle area when entering into sections;2)when pedestrians wear glasses with 0%illumination,pedestrians would like to choose left side of stairs(inner stairs)rather than middle and right side of stairs(outside stairs).Furthermore,illumination and the use of handrails have an effect on evacuation in stairwells.The less illumination is,the slower speed is;the use of handrails helps to reduce the time spent on interfaces or mid-landings with 100%or 12%illumination condition.Some experiments were carried out in a real staircase in which many people merged under a variety of circumstances,In addition,to study the effect of illumination on movement characteristics,pedestrians were asked to wear glasses with different luminousness,namely 100%and 12%illumination.Through data collection and analysis,it is found there are three phases(free movement phase,extended zipper effect phase and following movement phase)during merging process.It is induced that merging behaviors negatively affect the speed from upstairs according to p-values and comparison between speeds before and after merging.And it can be clearly seen that for all scenarios the speeds of pedestrians decrease and then tend to be steady with the development of time they come into the merging area.At last,the merging behaviors are influenced by illumination and initial merging ratios:occupants from floor are more than that from upstairs,contributing high density at the merging area in regardless of illuminations.In addition,a new stair model(Block-based Stair Model)is proposed by taking advantage of block-based floor field and Optimal Step Model.For the purpose of validation of the model,experimental speeds of individuals with 100%illumination were inserted into the model to reproduce the merging behaviors,in order to compare with the data in merging experiments.Then movements on stairs were simulated and studied with the help of Block-based Stair Model,in order to reproduce movement at mid-landing and study performance of occupants in stairwell.The simulated results perform well in respect of specific flow and fundamental diagram.Lane formations on stairs conme into being bcefore mid-landing area through simulations,which is in accord with the self-organized behaviors of occupants in real life.And there are four lanes due to numerical relationship of stairs width and occupants radius.At last the model is implemented to study the effect of four stairs geometry on merging behaviors.In particularly,stair structure in scenario c is biased in favor of occupants from floor,which agrees with the results in our experiments.As last,the major work in this paper was presented,and corresponding innovations and further research aspects base on this work were also presented.