UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item THE COMPARISON OF TOTAL AND PHASED EVACUATION STRATEGIES FOR A HIGH-RISE OFFICE BUILDING(2019) Zhai, Luying; Milke, James A; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This research work aims to explore the difference between total and phased evacuation strategies in high-rise office buildings and provide guidance on evacuation strategies for decision-makers in determining allowable occupant load. This work focuses on evaluating the principal factors (building height and occupant load) that may have an impact on egress time and provides a comparison of total versus phased evacuation in a hypothetical high-rise office building through a computer simulation using MassMotion. The comparison is separated into two aspects: total egress time and floor clearing time. The current thesis determined that the difference of total egress time between these two strategies increases with increased building height. The difference of total egress time between total and phased evacuation is from 165 to 878 seconds with the heights of building from 11 stories to 31 stories, respectively. The floor clearing time for the affected floors is similar in total evacuation strategy in different building heights. Also, in various building heights, the floor clearing time for affected floors has little difference in phased evacuation strategy. Moreover, this thesis depicted a graph of the floor clearing time in these two fire strategies with different occupant load factors. If a phased evacuation strategy is implemented, a decrease in the occupant load factor can be accommodated which results in the same floor clearing time as for a total evacuation strategy. The current thesis generated an equation to estimate the decrease in the occupant load factor between total and phased evacuation based on the same floor clearing time. There is a limited research work available for the comparison of total and phased evacuation. This research work provides guidance for building planners and engineers in determining total and phased evacuation strategies for high-rise office buildings. For the buildings studied, an equation is provided for engineers to quantify the impact of differences in total and phased evacuations.Item DEVELOPMENT OF A MIXED-FLOW OPTIMIZATION SYSTEM FOR EMERGENCY EVACUATION IN URBAN NETWORKS(2012) Zhang, Xin; Chang, Gang-len; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In most metropolitan areas, an emergency evacuation may demand a potentially large number of evacuees to use transit systems or to walk over some distance to access their passenger cars. In the process of approaching designated pick-up points for evacuation, the massive number of pedestrians often incurs tremendous burden to vehicles in the roadway network. Hence, one critical issue in a multi-modal evacuation planning is the effective coordination of the vehicle and pedestrian flows by considering their complex interactions. The purpose of this research is to develop an integrated system that is capable of generating the optimal evacuation plan and reflecting the real-world network traffic conditions caused by the conflicts of these two types of flows. The first part of this research is an integer programming model designed to optimize the control plans for massive mixed pedestrian-vehicle flows within the evacuation zone. The proposed model, integrating the pedestrian and vehicle networks, can effectively account for their potential conflicts during the evacuation. The model can generate the optimal routing strategies to guide evacuees moving toward either their pick-up locations or parking areas and can also produce a responsive plan to accommodate the massive pedestrian movements. The second part of this research is a mixed-flow simulation tool that can capture the conflicts between pedestrians, between vehicles, and between pedestrians and vehicles in an evacuation network. The core logic of this simulation model is the Mixed-Cellular Automata (MCA) concept, which, with some embedded components, offers a realistic mechanism to reflect the competing and conflicting interactions between vehicle and pedestrian flows. This study is expected to yield the following contributions * Design of an effective framework for planning a multi-modal evacuation within metropolitan areas; * Development of an integrated mixed-flow optimization model that can overcome various modeling and computing difficulties in capturing the mixed-flow dynamics in urban network evacuation; * Construction and calibration of a new mixed-flow simulation model, based on the Cellular Automaton concept, to reflect various conflicting patterns between vehicle and pedestrian flows in an evacuation network.Item An Investigation on the Effects of Firefighter Counterflow and Human Behavior in a Six-Story Building Evacuation(2007-03-13) Kratchman, Jessica Anne; Milke, James; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study provides an investigation into the fundamental assumptions made in many current egress models and serves as a case-control investigation regarding stairwell evacuations. The evacuation of a six-story office building was filmed and observed. The introduction of two-directional travel within the same stairwell was considered: the upward direction of firefighters trying to get into the building, and the downward direction of occupants trying to get out. This provided conditions outside the assumptions generally made. Also an investigation into human behavioral patterns has been considered. The effects of these conditions have been analyzed both qualitatively and quantitatively. Results demonstrate that the higher a person entered the stairwell the more significant the effects of counterflow became. The wing with counterflow maintained more dense conditions throughout the duration of the evacuation. Behavioral patterns such as carrying objects, socializing, nonadaptive behaviors, and interaction with the firefighters were determined to have a significant influence on the population's performance.