Dr. Hussam N. Mahmoud

Associate Professor and Director, Structural Laboratory

Department of Civil and Environmental Engineering

School of Biomedical Engineering

School of Advanced Materials Discovery

Research

Dr. Mahmoud's research program has three major thrusts including quantifying community resilience as well as assessing building damage to extreme single and multiple hazards and evaluating deteriorated infrastructure within the context of life-cycle analysis. The first thrust pertains to spatial and temporal determination of resilience for communities subjected to extreme natural hazards. This is realized through modeling and representing the hazard, assessing infrastructure damage, losses, and recovery, and estimating the socio-economic consequences within a community. The second thrust is focused on the development of resilient and sustainable structural systems subjected to natural and man-made hazards including single and multi-hazards. This is realized through devising engineering performance-based systems under fire, earthquakes, and wind or the combination of such. Various tools are utilized in Dr. Mahmoudís research for the assessment of structures under extreme demands include small and large-scale testing as well as advanced numerical and analytical simulations. Testing includes cyclic, pseudo-dynamic, hybrid simulations, shake table, and testing under elevated temperatures. The third major thrust pertains to evaluation, and repair of deteriorated infrastructure subjected to high and low-cycle fatigue. This includes assessment of remining fatigue life of steel bridges and hydraulic steel structures as well as proposing new retrofit methods for these structures.

Resilient Communities
Credit: http://osfm.fire.ca.gov Dr. Mahmoud is currently part of a national effort for developing physics-based models to predict recovery of communities following extreme hazards through a new $20 million NIST-funded Center of Excellence for Risk-Based Community Resilience Planning, led by Colorado State University. Through this effort, he is responsible for developing the next generation fragility curves for steel buildings, which can be used to conduct life-cycle cost analysis, accounting for socio-economic losses, to ultimately influence design code provisions. These fragilities are being used to quantifying the role steel buildings play in elevating resilience of communities. In addition, another ongoing research project pertains to devising several new family dwellings archetypes, subjected to the multi-hazard of extreme wind and expansive soils, with the goal of linking community resilience goals to individual building performance objectives.
Single and Multi-Hazard Response of Structures
Photo Credit: www.eqclearinghouse.org Dr. Mahmoudís current research includes evaluation of structural systems under fire, earthquake and wind. The emphasis is on developing new performance-based design approaches that focus on life-cycle cost analysis, with focus on steel structures, that will result in safe and cost-effective systems. These performance-based approaches hinge on accurate predictions of structural response, which is another focus of Dr. Mahmoudís research where he is currently working on developing new fatigue and fracture models that can be used to predict failures under extreme demands including connection fracture and system collapse. Expanding on existing cyclic fatigue models that account only for axial tension loading, the new models incorporate both axial tension and shear cycles or a combination of such. In doing so, wider range of stress triaxialities are investigated under realistic loading conditions.
Deteriorated Infrastructure
In the field of infrastructure deteriorations, Dr. Mahmoud is currently conducting research for the U.S. Army COE to evaluate alternative underwater fatigue retrofit methodologies and conduct for deteriorated hydraulic steel structure. In addition, new various studies are ongoing for assessing the multi-axial fatigue behavior of various structural components and systems utilized by the Army COE. The results of the ongoing tests and numerical analysis are being utilized for devising new inspection and repair plans for hydraulic steel structures that are based on minimum life-cycle cost analysis. In addition, ongoing research is being conducted for the Colorado Department of Transportation to quantifying the effect of deteriorated bridge joints on the life-cycle cost of steel bridges while accounting for the cost of inspection, maintenance, and repair.

Acknowledgement

Dr. Mahmoud sincerely appreciates and acknowledges all funding provided by state, federal, and national agencies as well as private sectors to support the research studies. Funding sources include the National Science Foundation, the U.S. Army Corps of Engineers, the Department of Defense, The national Institute of Standards and Technology, The Colorado Department of Transportation, The U.S. Department of Transportation, and Perscient. Thanks are also due to all undergraduate and graduate students and also to post-doctorate researchers and visiting scholars. In addition, collaboration with international universities, such as the University of Toronto and Tsinghua University, is acknowledged.