Colorado State University Associate Professor Hussam Mahmoud is developing novel computational models aimed at modeling the response of communities to multi-hazard disasters, including understanding the societal and economic impacts of events such as hurricanes and wildfires. His research is aimed at providing new, integrated information that can be leveraged for risk assessment, community planning and adaptation, emergency response planning, and communication with the public before, during, and after disasters strike.
In his most recent paper published in the journal Nature, “Unraveling the complexity of wildland-urban interface fires”, Mahmoud and co-author Ph.D. candidate Akshat Chulahwat report the development of a new, probabilistic approach, based in graph theory, for quantifying community vulnerability to wildfires. Their approach evaluates fire propagation probabilities across the domain, and uses these to quantify the vulnerability of a community via a computed vulnerability index. The model was calibrated using data from one of the most destructive wildfires in U.S. history, the 1991 Tunnel Fire in Oakland, CA, which resulted in 25 fatalities, 150 casualties and approximately US$ 1.5 billion in economic losses. Mahmoud and Chulahwat’s initial tests revealed the distance between ignitable structures as one of the key underlying factors affecting Oakland’s vulnerability to wildfires.
Mahmoud and Chulawat also developed a “hazard-agnostic,” finite element resilience model that they used to simulate “Gotham City under attack” via social, economic, and infrastructure disruptions. The results for the Gotham City test bed showed that a fast recovery from a disruption can lead to longer-term instabilities, suggesting that planning for the post-event re-establishment of community “lifelines” must consider the community as an integrated system if recovery is to be stable over the long term.
In this video, Mahmoud and his team show their predictions for the propagation of fire through a community, for specified environmental conditions that include ignition location, vegetation dryness, windspeed, and wind direction.
Multi-Hazard Hurricane Impact Level Model
The economic impacts of hurricanes on communities are often dominated not by the damage from high winds, but rather flooding, precipitation and storm surge. Mahmoud and Ph.D. candidate Stephanie Pilkington used a neural network framework for their Multi-Hazard Hurricane Impact Level Model that connects economic outcomes to traditional meteorological storm intensity metrics, population data, and building code information, training the network with data associated with historical tropical cyclones. The model can be used to test scenarios, such as the impacts expected if one of those historical storms were shifted to other locations along the U.S. coastline, or the extent to which policy changes or investments in resilient infrastructure such as seawalls would have reduced the economic impacts of storms of varying intensity.
INFRASTRUCTURE DETERIORATION RESEARCH
Mahmoud, trained as a structural engineer, is also interested in evaluating and mitigating deterioration to infrastructure particularly locks, dams, and bridges. In a recent study, he and his team conducted a series of laboratory tests to evaluate alternative underwater fatigue retrofit methodologies; their carbon fiber retrofit solution has been applied in a number of locations across the U.S. Mahmoud’s team is also interested in understanding structural response under extreme loads and was the first to conduct controlled laboratory studies on the combined impacts of stress and fire on structural beam integrity. These multihazard studies are providing new, urgently-needed data on the mechanisms by which structures fail when subjected to more than one stressor.
In this video, Mahmoud and his group conduct an experiment to evaluate the effect of the presence of cracking, which is a sign of aging and deterioration, on the capacity of the beam under applied load and elevated temperature
THE MAHMOUD GROUP
Hussam Mahmoud is an Associate Professor in the Department of Civil and Environmental Engineering in the Walter Scott, Jr. College of Engineering at Colorado State University, and is affiliated with the School of Biomedical Engineering and the School of Advanced Materials Discovery. He received his bachelor’s and master’s degrees in civil engineering from the University of Minnesota and his Ph.D. from the University of Illinois at Urbana-Champaign (UIUC). Prior to joining CSU, he held appointments as manager of the NEES Earthquake Laboratory at UIUC, where he oversaw and conducted various large-scale hybrid simulations. Prior to joining CSU, he held appointments as manager of the NEES Earthquake Laboratory at UIUC and research scientist at Lehigh University. Mahmoud’s professional technical committee appointments include the ASCE Committee on Fire Protection and the ASCE Committee on Multi-Hazard Mitigation. He is currently the elected chair of the ASCE Committee on Fatigue and Fracture and of the ASCE Committee on Steel Bridges, and he is a member of the Steel Bridge Task Force of The American Iron and Steel Institute (AISI). He has been an Invited Visiting Scholar at Tsinghua University in Beijing, an Air Force Faculty Fellow at AFIT Wright Paterson Laboratory, and an invited participant in five National Academy of Science, Engineering, and Medicine symposia, including the 2015 US Frontiers of Engineering Symposium.
Mahmoud presently serves as the Director of the Structural Laboratory at CSU and is a member of the Engineering Researcher Team for the Center for Risk-Based Community Resilience Planning, a NIST-funded Center of Excellence supporting a collaboration involving engineers, social scientists, and economists from 10 universities and NIST. Mahmoud’s research program has three major thrusts: assessing community resilience, quantifying building damage to extreme single and multiple hazards, and evaluating deteriorated infrastructure.
“Wildfires are a part of nature, both inevitable and necessary, pointing to only one foregone conclusion: wildfire management needs to be driven by regulating vulnerability of communities.”
Make the connection
Mahmoud is among a number of researchers in the Walter Scott, Jr. College of Engineering whose research is inspired by biological systems. Jianguo Zhao, assistant professor of mechanical engineering, develops biologically-inspired robots with various locomotion capabilities for applications that include search and rescue, surveillance, and environmental monitoring. Zhao was recently awarded a Computer and Information Science and Engineering (CISE) Research Initiation Initiative Award (CRII) from the National Science Foundation to develop a robot with novel, autonomous shape morphing capabilities.
Zhao’s goal is to leverage varying shapes from the same structure for robotic locomotion in different environments, accomplishing similar multi-modal locomotion as exhibited in nature: for example, frogs can swim with legs and sea lions can walk with flippers.