Pedestrian flow through exit:Study focused on evacuation pattern

Experiments are conducted on the evacuation rate of pedestrians through exits with queued evacuation pattern and random evacuation pattern. The experimental results show that the flow rate of pedestrians is larger with the random evacuation pattern than with the queued evacuation pattern. Therefore, the exit width calculated based on the minimum evacuation clear width for every 100 persons, which is on the assumption that the pedestrians pass through the exit in one queue or several queues, is conservative. The number of people crossing the exit simultaneously is greater in the random evacuation experiments than in the queued evacuation experiments, and the time interval between the front row and rear row of people is shortened in large-exit conditions when pedestrians evacuate randomly. The difference between the flow rate with a queued evacuation pattern and the flow rate with a random evacuation pattern is related to the surplus width of the exit, which is greater than the total width of all accommodated people streams. Two dimensionless quantities are defined to explore this relationship. It is found that the difference in flow rate between the two evacuation patterns is stable at a low level when the surplus width of the exit is no more than 45% of the width of a single pedestrian stream. There is a great difference between the flow rate with the queued evacuation pattern and the flow rate with the random evacuation pattern in a scenario with a larger surplus width of the exit. Meanwhile, the pedestrians crowd extraordinarily at the exit in these conditions as well, since the number of pedestrians who want to evacuate through exit simultaneously greatly exceeds the accommodated level. Therefore, the surplus width of exit should be limited especially in the narrow exit condition, and the relationship between the two dimensionless quantities mentioned above could provide the basis to some extent.

Investigating impacts of different building contents on the post-earthquake evacuation time using an agent-based model with considering turning behavior

Accurate assessment of crowd evacuation inside the post-earthquake environment is critical from many perspectives,but this issue receives much less attention compared to the seismic losses of structural and non-structural components.This could be attributed to the fact that post-earthquake evacuation analysis is complex due to the interaction between human behavior and the actual built environment induced by different building contents.This study attempts to tackle this problem by investigating the impacts of different building contents on post-earthquake evacuation time by using an agent-based model that considers turning behavior.To this end,the agent-based model is first described,including:properties of the agent-based model with turning behavior,key aspects in its formulation considering different evacuation stages,and influence of different building contents(namely,debris from partition walls and ceiling systems,and various types of equipment)on the agent’s behavior.Subsequently,a school building is used as a benchmark problem to validate the model without earthquake,and the findings indicate that the agent-based model can match the real safety drill results reasonably well.After the validation,the school building is subsequently designed in accordance with modern seismic design codes,and the influence of debris and equipment on post-earthquake evacuation time is quantitatively studied using a suite of pulse-type ground motions as input.Based on this case study,recommendations are made for structural and architectural designers in an effort to reduce the potential evacuation time.Specifically,debris induced by partition walls or ceiling systems should be controlled as it has the greatest impact on the total evacuation time.

Study on Evacuation Strategy of Commercial High-Rise Building under Fire Based on FDS and Pathfinder

With the development of economy and society and the growth of population,the high-rise and multi-function of commercial buildings have become an international trend.But it also poses huge fire hazards.Most of the existing studies’research objects are predominantly high-rise residential buildings,without considering the impact of different functional zones(Standard floor,entertainment zone,office zone,equipment room and so on)and personnel distribution of commercial buildings evacuation.And the influence of using elevators to carry evacuees on the refuge floor on personnel evacuation is rarely studied.In this work,the fire scenario of the Yangtze River InternationalConferenceCenter,a high-rise commercial building,is simulated with the Pyrosim programto get the necessary parameters under various fire scenarios and to calculate the available evacuation time TASET.At the same time,according to the complex functional zone of the commercial high-rise building and the distribution of people in different time periods,a reasonable evacuation strategy is developed and simulated by Pathfinder software.The results indicate that unorganized evacuation will lead individuals to take the erroneous evacuation route,resulting in a vast region of congestion;comprehensive consideration of the time staggering and the reasonable distribution of evacuation routes can significantly improve evacuation efficiency,and the TRSET of night and working hours is 36.6%–55.3%and 49.9%–79.6%of unorganized evacuation,respectively.For the night fire,60%of the people use elevator-refuge floor to evacuate is the optimal strategy;for the fire during working hours,half of the people on standard floors use the elevator to evacuate and people on multifunctional floors evacuate in four batches is the best plan.The results of this study can provide viable solutions and a foundation for analyzing the fire evacuation and safety of big commercial high-rise buildings.

A Game-Theoretic Approach to Safe Crowd Evacuation in Emergencies

Obstacle removal in crowd evacuation is critical to safety and the evacuation system efficiency. Recently, manyresearchers proposed game theoreticmodels to avoid and remove obstacles for crowd evacuation. Game theoreticalmodels aim to study and analyze the strategic behaviors of individuals within a crowd and their interactionsduring the evacuation. Game theoretical models have some limitations in the context of crowd evacuation. Thesemodels consider a group of individuals as homogeneous objects with the same goals, involve complex mathematicalformulation, and cannot model real-world scenarios such as panic, environmental information, crowds that movedynamically, etc. The proposed work presents a game theoretic model integrating an agent-based model to removethe obstacles from exits. The proposed model considered the parameters named: (1) obstacle size, length, andwidth, (2) removal time, (3) evacuation time, (4) crowd density, (5) obstacle identification, and (6) route selection.The proposed work conducts various experiments considering different conditions, such as obstacle types, obstacleremoval, and several obstacles. Evaluation results show the proposed model’s effectiveness compared with existingliterature in reducing the overall evacuation time, cell selection, and obstacle removal. The study is potentially usefulfor public safety situations such as emergency evacuations during disasters and calamities.

The Impact of Sea Level Rise on Roadway Design and Evacuation Routes in Delaware

As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.

Research on Evacuation Path Planning Based on Improved Sparrow Search Algorithm

Reducing casualties and property losses through effective evacuation route planning has been a key focus for researchers in recent years.As part of this effort,an enhanced sparrow search algorithm(MSSA)was proposed.Firstly,the Golden Sine algorithm and a nonlinear weight factor optimization strategy were added in the discoverer position update stage of the SSA algorithm.Secondly,the Cauchy-Gaussian perturbation was applied to the optimal position of the SSA algorithm to improve its ability to jump out of local optima.Finally,the local search mechanism based on the mountain climbing method was incorporated into the local search stage of the SSA algorithm,improving its local search ability.To evaluate the effectiveness of the proposed algorithm,the Whale Algorithm,Gray Wolf Algorithm,Improved Gray Wolf Algorithm,Sparrow Search Algorithm,and MSSA Algorithm were employed to solve various test functions.The accuracy and convergence speed of each algorithm were then compared and analyzed.The results indicate that the MSSA algorithm has superior solving ability and stability compared to other algorithms.To further validate the enhanced algorithm’s capabilities for path planning,evacuation experiments were conducted using different maps featuring various obstacle types.Additionally,a multi-exit evacuation scenario was constructed according to the actual building environment of a teaching building.Both the sparrow search algorithm and MSSA algorithm were employed in the simulation experiment for multiexit evacuation path planning.The findings demonstrate that the MSSA algorithm outperforms the comparison algorithm,showcasing its greater advantages and higher application potential.

The Many Facets of History:A Study on the Accounts of the Dunkirk Evacuation

This paper adopts a New Historicism approach to examine the shaping of the history of the Dunkirk evacuation through an analysis of Winston Churchill’s historic speech We Shall Fight on the Beaches,Ian McEwan’s novel Atonement,and Christopher Nolan’s film Dunkirk.The research reveals that by uncovering and representing the neglected stories of marginalized groups in Atonement and Dunkirk,new evidentiary threads both enrich and contest the History embodied in Churchill’s speech.Consequently,these alternative accounts both challenge and complement the prevailing historical discourse.

Integrating AnyLogic Simulation in Emergency Evacuation Management for Enhanced Security

This study introduces an innovative approach by integrating AnyLogic simulation into emergency evacuation strategies to enhance security protocols.The research focuses on leveraging advanced computational models to simulate and optimize evacuation scenarios in various settings,including public venues,residential areas,and urban environments.By integrating real-world data and behavioral models,the simulation accurately represents human movements,decision-making processes,and traffic flow dynamics during evacuation scenarios.The study evaluates the effectiveness of various evacuation strategies,including route planning,crowd behavior,and emergency response coordination,using a scenario-driven approach within the AnyLogic simulation environment.Furthermore,this research contributes to the establishment of optimized emergency response protocols by systematically evaluating and refining evacuation plans.The research frameworks mentioned in the research imply the efficient use of the AnyLogic simulation model to be used in different sectors and fields to enhance the strategies for saving lives and implementing an efficient evacuation management system.

Effect of a static pedestrian as an exit obstacle on evacuation

Building exit as a bottleneck structure is the last and the most congested stage in building evacuation.It is well known that obstacles at the exit affect the evacuation process,but few researchers pay attention to the effect of stationary pedestrians(the elderly with slow speed,the injured,and the static evacuation guide)as obstacles at the exit on the evacuation process.This paper explores the influence of the presence of a stationary pedestrian as an obstacle at the exit on the evacuation from experiments and simulations.We use a software,Pathfinder,based on the agent-based model to study the effect of ratios of exit width(D)to distance(d)between the static pedestrian and the exit,the asymmetric structure by shifting the static pedestrian upward,and types of obstacles on evacuation.Results show that the evacuation time of scenes with a static pedestrian is longer than that of scenes with an obstacle due to the unexpected hindering effect of the static pedestrian.Different ratios of D/d have different effects on evacuation efficiency.Among the five D/d ratios in this paper,the evacuation efficiency is the largest when d is equal to 0.75D,and the existence of the static pedestrian has a positive impact on evacuation in this condition.The influence of the asymmetric structure of the static pedestrian on evacuation efficiency is affected by D/d.This study can provide a theoretical basis for crowd management and evacuation plan near the exit of complex buildings and facilities.

Pedestrian evacuation simulation in multi-exit case:An emotion and group dual-driven method

This paper analyzes the characteristics of emotion state and group behavior in the evacuation process.During the emergency evacuation,emotion state and group behavior are interacting with each other,and indivisible.The emotion spread model with the effect of group behavior,and the leader-follower model with the effect of emotion state are proposed.On this basis,exit choice strategies with the effect of emotion state and group behavior are proposed.Fusing emotion spread model,leader-follower model,and exit choice strategies into a cellular automata(CA)-based pedestrian simulation model,we simulate the evacuation process in a multi-exit case.Simulation results indicate that panic emotion and group behavior are two negative influence factors for pedestrian evacuation.Compared with panic emotion or group behavior only,pedestrian evacuation efficiency with the effects of both is lower.

Model considering panic emotion and personality traits for crowd evacuation

Panic is a common emotion when pedestrians are in danger during the actual evacuation, which can affect pedestrians a lot and may lead to fatalities as people are crushed or trampled. However, the systematic studies and quantitative analysis of evacuation panic, such as panic behaviors, panic evolution, and the stress responses of pedestrians with different personality traits to panic emotion are still rare. Here, combined with the theories of OCEAN(openness, conscientiousness,extroversion, agreeableness, neuroticism) model and SIS(susceptible, infected, susceptible) model, an extended cellular automata model is established by the floor field method in order to investigate the dynamics of panic emotion in the crowd and dynamics of pedestrians affected by emotion. In the model, pedestrians are divided into stable pedestrians and sensitive pedestrians according to their different personality traits in response to emotion, and their emotional state can be normal or panic. Besides, emotion contagion, emotion decay, and the influence of emotion on pedestrian movement decision-making are also considered. The simulation results show that evacuation efficiency will be reduced, for panic pedestrians may act maladaptive behaviors, thereby making the crowd more chaotic. The results further suggest that improving pedestrian psychological ability and raising the standard of management can effectively increase evacuation efficiency. And it is necessary to reduce the panic level of group as soon as possible at the beginning of evacuation. We hope this research could provide a new method to analyze crowd evacuation in panic situations.

Pathfinder-Based Simulation and Optimization of Evacuation of Large Commercial Complexes

Large commercial complexes are large in scale, complex in function, and located in densely populated areas that are prone to casualties due to unfavorable evacuation. To comprehend the safety evacuation of large commercial complex buildings in China, investigate the safety evacuation problems encountered during the evacuation process and the evacuation optimization design strategy, the paper uses Pathfinder to build a simulation model based on literature research and study to simulate the evacuation of personnel in a large commercial complex in Dalian and explore its problems during the evacuation process. The results show that the type of personnel has an effect on the large commercial complex’s evacuation simulation results;the total number of evacuees is non-linearly correlated with the time change curve;some staircases take a long time to evacuate and have a low utilization rate. To improve evacuation efficiency, optimization suggestions for safety exits, evacuation stairs, and evacuation channels are made based on the results.

Sanitary Evacuations at the Maternity Unit of the Social Hygiene Institute (IHS) in Dakar in 2020

Objective: Determine the frequency of evacuations, specify the epidemiological and clinical characteristics of the evacuees, evaluate the data of the evacuation, the management and the maternal-fetal prognosis. Methods: Prospective and descriptive retrospective study concerning obstetrical evacuations received at the maternity ward of the Hospital of the Institute of Social Hygiene in Dakar between January 1 and December 31, 2020, i.e. a period of 12 months. Results: During the study period, we collected 1156 evacuees out of a total of 3507 patients treated in the Service, i.e. a frequency of 33%. The average age of the patients was 27.07 years with extremes of 14 and 46 years. Patients aged between 20 and 29 were the most represented (51.73%). The average parity was 1.6 with extremes of 0 and 10 pares. The nulliparous (46.37%) were the majority. The majority of evacuated patients (99.6%) resided in the Dakar region, including 58% in the suburbs and 42% in the city center. The patients received had performed an average of 3 prenatal consultations with extremes ranging from 0 to 9 CPN. They most often came from health centers (55.05%) or hospitals (29.09%). The reasons for evacuations were dominated by dystocia (21.54%) followed by premature rupture of membranes (17.21%) and premature deliveries (16.35%). On admission, only 176 patients (15.2%) had an evacuation sheet. Patients transited on average through two health structures (extremes ranging from 0 to 7 structures) before reaching the reception structure. The evacuation was most often done with a private vehicle on the patient’s own means (91.96%). The outcome of the evacuees was most often vaginal delivery or hospitalization (72.79%). The majority of patients (99.4%) had evolved favorably but we deplore one maternal death (0.09%) linked to a late puerperal infection. We recorded 74 perinatal deaths and 1041 live births, i.e. a stillbirth rate of 71.1‰ live births. The causes of death were dominated by prematurity (24.7%). Conclusion: Obstetrical evacuations are frequent in our practice but they should be better organized to improve the maternal-fetal prognosis.

监测与仿真协同的实验室智能应急疏散系统研究

高校实验室是消防安全管理的重点,常规消防疏散指示牌方向固定,无法根据火情变化实时调整指引逃生路线,该文设计了一种基于监测与路径仿真协同的实验室智能消防应急疏散系统,基于YOLOv5s框架监测人流量,利用Pathfinder对疏散路径进行规划,以逃生时间最短为目标计算疏散路径,实现了火灾信息自动采集和疏散方向智能指引。在两种模拟火灾场景下疏散效率分别提高了19.95%和12.71%,有效降低了消防疏散风险。

地下隧道竖向疏散现场试验研究

近年来,隧道的疏散设计中普遍应用竖向疏散模式,但该模式的安全性缺少真实试验数据支撑和验证。为探究隧道竖向疏散模式下的人员疏散行为特征及关键参数,采用现场试验的方法,在某隧道内搭建火灾时的交通堵塞场景,组织188名参与者(109名男性,79名女性)开展大规模人群疏散研究,针对人员疏散时间、疏散行走速度、疏散楼梯人员通行能力、疏散楼梯盖板开启时间等参数进行分析。研究结果表明:1)隧道火灾时,人员疏散受到隧道熟悉度和疏散引导的显著影响,在紧急疏散过程中更容易发生拥堵,疏散引导可极大地改善人员的出口及路径选择,提高疏散效率。2)交通堵塞状态下,人员疏散行走速度因隧道熟悉度的提高和疏散引导而显著提高。行车道上,男性和女性的平均速度分别由1.38 m/s、1.39 m/s提高至1.94 m/s、1.99 m/s。但在下部安全疏散通道内,参与者出现懈怠和放松的情绪,平均疏散行走速度会略有降低。应考虑在疏散通道内设置一些警示标志以督促引导人员疏散。3)入口宽度为1.09 m的疏散楼梯的最大人员通行能力为38人/min;男性参与者开启楼梯盖板的平均时间为7.5 s,女性参与者开启楼梯盖板的平均时间为12.6 s,相比于女性,男性参与者更容易打开楼梯盖板。研究结果可为隧道疏散逃生方案设计、运营管理提供真实试验数据参考,提高隧道防灾疏散水平。

考虑恐慌行人和多救援人员分区引导的疏散研究

为了探究紧急情况下多救援人员对恐慌行人疏散的影响,建立了一个考虑恐慌行人和多救援人员分区引导的元胞自动机扩展模型。首先,在模型中引入了恐慌因子Pm(t)定量反应恐慌情绪对行人疏散的影响;然后,考虑当多个救援人员存在时,协作开展分区救援的行为;最后,通过仿真重点分析了恐慌情绪阈值、救援人员数量及危险源位置对疏散动力学的影响。结果表明:恐慌情绪阈值和危险源位置显著影响人群的恐慌传播过程和疏散过程;救援人员的引导提高了疏散效率;当多名救援人员存在时,实行分区引导更有利于疏散;出现救援人数不足时,根据危险源的位置和恐慌传播过程对疏散的影响合理地分配救援人员能够提高疏散效率。

考虑折返行为的元胞自动机人员疏散模型

为研究行人折返行为对疏散的影响,考虑多出口对行人的吸引力、人员相互作用力、火源蔓延威胁以及折返场吸引力的共同影响,在元胞自动机模型的基础上提出基于静态场、动态场、火源场以及折返场共同作用的行人疏散场域模型,研究不同折返比例、折返区域、人员密度、出口数量和位置情况下折返行为对疏散进程的影响。研究结果表明:少量折返行为对总疏散时间影响较小,而群体性折返行为的存在会增加总体疏散时间,随着折返比例的增加,疏散时间随之增加。折返区域离出口越近,对总体疏散效率的影响越小。折返行为对疏散进程的影响效果,随着人员密度的增加不断增强。在双出口条件下,对侧设置出口位置能有效减少折返行为对疏散进程的负面影响。研究结果可为提高紧急情况下的疏散效率提供参考。

不同姿态人群的火场疏散模型研究

在火灾疏散中,火场高温烟气带来的物理威胁和心理压力会对人员疏散产生影响。为了量化火灾环境下人员可能采用的弯腰、爬行等疏散姿态及其与火源间的交互对疏散过程的影响,采用椭圆表征行人不同的运动姿态,考虑火源产生的物理和心理影响,基于社会力模型建立了一种混合姿态火场疏散模型。本模型能够再现试验中观测到的行人绕行及避让火源行为,可根据火源状态提前规划疏散路径避开高温区域。研究发现,当人员采用爬行、蹲行和弯腰行走三种姿态疏散时,人群的疏散时间随密度和火源温度升高而延长。随着路径风险差异增大和行人危险敏感度提高,选择安全路径的行人比例逐渐增大。研究可以为火灾环境下人员的安全应急疏散管理提供技术支持。

基于DEMATEL-ISM模型的地铁火灾疏散影响因素研究

为减少地铁火灾事故对人员及财产安全的威胁,提升地铁火灾疏散安全性,对地铁火灾疏散影响因素进行系统性研究。在构建地铁火灾疏散影响因素指标体系的基础上,将决策实验室分析法(DEMATEL)与解释结构模型(ISM)联合,用于研究各因素对地铁火灾疏散系统的重要程度,并对各因素间的逻辑结构进行梳理分析。结果表明,恐慌心理和火灾产物分别为影响地铁火灾疏散系统安全性的关键性直接因素和根本因素,24个地铁火灾疏散影响因素可划分为3层5阶的递阶结构。此研究有助于科学认识地铁火灾疏散系统,对提高实际疏散安全性具有参考价值。

老旧教学楼火灾场景人员疏散仿真研究

为提高老旧教学楼火灾场景下人员应急疏散能力,建立一个老旧教学楼火灾人员疏散模型。运用PyroSim软件建立火灾扩散模型,模拟分析该教学楼在机械排烟、自动喷淋和着火房间窗户是否开启的情况下,发生火灾时着火楼层安全出口处的烟气能见度、温度和CO的变化规律;结合Pathfinder软件对出口状态、人员疏散进行模拟仿真,得到人员全部疏散完成时所需安全疏散时间。实验结果表明:老旧教学楼无喷淋时人员疏散效率降低12.1%,无机械排烟时人员疏散处于危险状态,多设出口对提升人员疏散效率影响较小。