Graduate Studies

 

First Advisor

Lily Wang

Second Advisor

Jennifer Lather

Degree Name

Doctor of Philosophy (Ph.D.)

Committee Members

Christine Wittich, Milad Roohi, Zhenghong Tang

Department

Architectural Engineering

Date of this Version

8-2025

Document Type

Dissertation

Citation

A dissertation presented to the Graduate College of the University of Nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy

Major: Architectural Engineering

Under the supervision of Professors Lily Wang and Jennifer Lather

Lincoln, Nebraska, August 2025

Comments

Copyright 2025, S. Yasaman Ahmadi. Used by permission

Abstract

The overarching goal of this dissertation is to develop an integrated, simulation-driven framework to assess and enhance the resilience of interdependent transportation and healthcare systems before, during, and after natural hazards. By examining how spatial disruptions, social vulnerability, operational constraints, and infrastructure interdependencies affect access to and functionality of hospitals, this research offers a multifaceted evaluation of system performance under stress. This dissertation examines the impact of natural hazards, particularly floods, on the interdependent transportation and healthcare systems. The proposed approach combines and advances GIS-based network analysis, graph-theoretical modeling, and discrete-event simulation to evaluate system performance under different scenarios. The goal is to provide practical solutions that support natural hazards preparedness, protect vulnerable communities, and reduce delays in emergency care.

Key findings show that flood-related transportation disruptions significantly reduced timely access to hospitals, especially for socially vulnerable populations. Simulations revealed that removing a single hospital due to flooding could double the number of census tracts experiencing hospital overcapacity, many of which are in already underserved communities. The research also found that targeted recovery strategies, focusing on restoring the most critical roads first, led to faster access restoration compared to uniform approaches. At the facility level, a hospital layout study using real patient flow data demonstrated that layouts optimized for surge conditions not only performed better during surges but also improved operational efficiency under normal conditions. Together, these findings offer a simulation-driven framework that can support more equitable, flexible, and resilient hazard planning. This work provides practical tools for transportation planners, healthcare facility designers, and emergency managers to better prepare for and respond to future disruptions, especially in communities with higher vulnerability.

Advisors: Lily Wang and Jennifer Lather

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