This page has only limited features, please log in for full access.
Special concentrically braced frames (SCBFs) located in regions close to earthquake faults may be subjected to near-fault ground motions, often characterized by pulses with long periods. These near-fault pulses could impose additional seismic demands on structures and increase the risk for structural collapse. Currently, there is limited research on the seismic collapse risk of SCBFs under near-fault earthquakes. This paper uses a general simulation-based framework to assess the seismic collapse risk of SCBFs under near-fault earthquakes. To quantify the large variability and uncertainty associated with the seismic hazard, a stochastic ground motion (SGM) model is used where the near-fault pulse characteristics are explicitly incorporated. The uncertainties in the SGM model parameters (including the near-fault pulse characteristics) are addressed through appropriate selection of probability distribution functions. To accurately predict the occurrence of collapse, numerical models capable of capturing the nonlinear and collapse behavior are established and used. Efficient stochastic simulation approaches are proposed to estimate the seismic collapse risk with or without considering the near-fault pulse. As an illustration, the seismic collapse risks of two SCBFs are investigated and compared. Probabilistic sensitivity analysis is also carried out to investigate the importance of uncertain model parameters within the SGM towards the seismic collapse risk.
Jeet Kumar Sonwani; Gaofeng Jia; Hussam N. Mahmoud; Zhenqiang Wang. Seismic Collapse Risk Assessment of Braced Frames under Near-Fault Earthquakes. Metals 2021, 11, 1271 .
AMA StyleJeet Kumar Sonwani, Gaofeng Jia, Hussam N. Mahmoud, Zhenqiang Wang. Seismic Collapse Risk Assessment of Braced Frames under Near-Fault Earthquakes. Metals. 2021; 11 (8):1271.
Chicago/Turabian StyleJeet Kumar Sonwani; Gaofeng Jia; Hussam N. Mahmoud; Zhenqiang Wang. 2021. "Seismic Collapse Risk Assessment of Braced Frames under Near-Fault Earthquakes." Metals 11, no. 8: 1271.
Tornadoes pose a significant threat to residential communities, causing enormous physical damage and losses to their social fabric. The dominant type of single-family residential buildings in the USA is light-frame wood construction, which is especially susceptible to tornado effects. Previous studies considering resilience of light-frame wood buildings have focused primarily on assessing damage, developing damage functions, and exploring different repair methods. Studies related to sustainability have focused mainly on environmental impacts or carbon usage. Practically all of these studies have been geared to assessment of individual buildings. In this study, we couple resilience and sustainability to evaluate their tradeoffs or alignments at the community level from a life-cycle stance. The life-cycle cost and carbon footprint are reflected in the construction and repair of damages due to the tornado hazard, as well as regular repair and maintenance that occurs during the life of the residence. Uncertainties in the randomness in tornado occurrence, size of the tornado footprint, and variation in wind speed intensities within the tornado footprint, and capacities of the building structure and envelope play a significant role in building performance and are considered. We explore a number of repair strategies that might be adopted at the community level in decision-making and policy formulation for homeowners, home builders and community planners. These strategies provide a framework for integrating minimum cost and carbon footprint objectives in risk-informed decision-making, a topic that appears to be lacking in the literature.
Pramodit Adhikari; Hussam N. Mahmoud; Bruce R. Ellingwood. Life-cycle cost and sustainability analysis of light-frame wood residential communities exposed to tornados. Natural Hazards 2021, 1 -22.
AMA StylePramodit Adhikari, Hussam N. Mahmoud, Bruce R. Ellingwood. Life-cycle cost and sustainability analysis of light-frame wood residential communities exposed to tornados. Natural Hazards. 2021; ():1-22.
Chicago/Turabian StylePramodit Adhikari; Hussam N. Mahmoud; Bruce R. Ellingwood. 2021. "Life-cycle cost and sustainability analysis of light-frame wood residential communities exposed to tornados." Natural Hazards , no. : 1-22.
Reinforced concrete (RC) beams are basic elements used in the construction of various structures and infrastructural systems. When exposed to harsh environmental conditions, the integrity of RC beams could be compromised as a result of various deterioration mechanisms. One of the most common deterioration mechanisms is the formation of different types of corrosion in the steel reinforcements of the beams, which could impact the overall reliability of the beam. Existing classical reliability analysis methods have shown unstable results when used for the assessment of highly nonlinear problems, such as corroded RC beams. To that end, the main purpose of this paper is to explore the use of a structural reliability method for the multi-state assessment of corroded RC beams. To do so, an improved reliability method, namely the three-term conjugate map (TCM) based on the first order reliability method (FORM), is used. The application of the TCM method to identify the multi-state failure of RC beams is validated against various well-known structural reliability-based FORM formulations. The limit state function (LSF) for corroded RC beams is formulated in accordance with two corrosion types, namely uniform and pitting corrosion, and with consideration of brittle fracture due to the pit-to-crack transition probability. The time-dependent reliability analyses conducted in this study are also used to assess the influence of various parameters on the resulting failure probability of the corroded beams. The results show that the nominal bar diameter, corrosion initiation rate, and the external loads have an important influence on the safety of these structures. In addition, the proposed method is shown to outperform other reliability-based FORM formulations in predicting the level of reliability in RC beams.
Mohamed Ben Seghier; Behrooz Keshtegar; Hussam Mahmoud. Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture. Materials 2021, 14, 1820 .
AMA StyleMohamed Ben Seghier, Behrooz Keshtegar, Hussam Mahmoud. Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture. Materials. 2021; 14 (8):1820.
Chicago/Turabian StyleMohamed Ben Seghier; Behrooz Keshtegar; Hussam Mahmoud. 2021. "Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture." Materials 14, no. 8: 1820.
Approximately 10% of the world’s population lives and works in low-lying coastal regions that are less than 10 meters above sea level. This percentage is likely to increase during the remainder of the 21st century due to population growth and economic development. This growth brings the potential for increasing damage and economic losses due to tropical cyclones (hurricanes in North America) accompanied by storm surge and sea-level rise (SLR) in an era of climate change. This study reviews and critically appraises the potential impact of the aforementioned multi-hazards on a typical coastal seaport community in the Gulf Coast of the United States. A new model for quantifying the functionality of seaports subject to these multi-hazards is implemented in a fault tree analysis. An analysis to enable the study the impact of hurricanes, storm surge and SLR on port facilities is validated using data from Hurricane Katrina. A case study of the Port of Mobile, AL reveals that if a Katrina-like hurricane were to occur late in the 21st Century, damages to the Port of Mobile would increase by a factor of nearly 7 under an RCP 8.5 scenario when compared to the damages caused by Hurricane Katrina alone.
Mohamed A. Abdelhafez; Bruce Ellingwood; Hussam Mahmoud. Vulnerability of seaports to hurricanes and sea level rise in a changing climate: A case study for mobile, AL. Coastal Engineering 2021, 167, 103884 .
AMA StyleMohamed A. Abdelhafez, Bruce Ellingwood, Hussam Mahmoud. Vulnerability of seaports to hurricanes and sea level rise in a changing climate: A case study for mobile, AL. Coastal Engineering. 2021; 167 ():103884.
Chicago/Turabian StyleMohamed A. Abdelhafez; Bruce Ellingwood; Hussam Mahmoud. 2021. "Vulnerability of seaports to hurricanes and sea level rise in a changing climate: A case study for mobile, AL." Coastal Engineering 167, no. : 103884.
The risk of overwhelming hospitals from multiple waves of COVID-19 is yet to be quantified. Here, we investigate the impact of different scenarios of releasing strong measures implemented around the U.S. on COVID-19 hospitalized cases and the risk of overwhelming the hospitals while considering resources at the county level. We show that multiple waves might cause an unprecedented impact on the hospitals if an increasing number of the population becomes susceptible and/or if the various protective measures are discontinued. Furthermore, we explore the ability of different mitigation strategies in providing considerable relief to hospitals. The results can help planners, policymakers, and state officials decide on additional resources required and when to return to normalcy.
Emad M. Hassan; Hussam N. Mahmoud. Impact of multiple waves of COVID-19 on healthcare networks in the United States. PLOS ONE 2021, 16, e0247463 .
AMA StyleEmad M. Hassan, Hussam N. Mahmoud. Impact of multiple waves of COVID-19 on healthcare networks in the United States. PLOS ONE. 2021; 16 (3):e0247463.
Chicago/Turabian StyleEmad M. Hassan; Hussam N. Mahmoud. 2021. "Impact of multiple waves of COVID-19 on healthcare networks in the United States." PLOS ONE 16, no. 3: e0247463.
The current COVID-19 pandemic has demonstrated the vulnerability of healthcare systems worldwide. When combined with natural disasters, pandemics can further strain an already exhausted healthcare system. To date, frameworks for quantifying the collective effect of the two events on hospitals are nonexistent. Moreover, analytical methods for capturing the dynamic spatiotemporal variability in capacity and demand of the healthcare system posed by different stressors are lacking. Here, we investigate the combined impact of wildfire and pandemic on a network of hospitals. We combine wildfire data with varying courses of the spread of COVID-19 to evaluate the effectiveness of different strategies for managing patient demand. We show that losing access to medical care is a function of the relative occurrence time between the two events and is substantial in some cases. By applying viable mitigation strategies and optimizing resource allocation, patient outcomes could be substantially improved under the combined hazards.
Emad M. Hassan; Hussam N. Mahmoud. Orchestrating performance of healthcare networks subjected to the compound events of natural disasters and pandemic. Nature Communications 2021, 12, 1 -12.
AMA StyleEmad M. Hassan, Hussam N. Mahmoud. Orchestrating performance of healthcare networks subjected to the compound events of natural disasters and pandemic. Nature Communications. 2021; 12 (1):1-12.
Chicago/Turabian StyleEmad M. Hassan; Hussam N. Mahmoud. 2021. "Orchestrating performance of healthcare networks subjected to the compound events of natural disasters and pandemic." Nature Communications 12, no. 1: 1-12.
Healthcare and education systems have been identified by various national and international organizations as the main pillars of communities’ stability. Understanding the correlation between these main social services institutions is critical to determining the tipping point of communities following natural disasters. Despite being defined as social services stability indicators, to date, no studies have been conducted to determine the level of interdependence between schools and hospitals and their collective influence on their recoveries following extreme events. In this study, we devise an agent-based model to investigate the complex interaction between healthcare and education networks and their overall recovery, while considering other physical, social, and economic factors. We employ comprehensive models to simulate the functional processes within each facility and to optimize their recovery trajectories after earthquake occurrence. The results highlight significant interdependencies between hospitals and schools, including direct and indirect relationships, suggesting the need for collective coupling of their recovery to achieve full functionality of either of the two systems following natural disasters. Recognizing this high level of interdependence, we then establish a social services stability index, which can be used by policymakers and community leaders to quantify the impact of healthcare and education services on community resilience and social services stability.
Emad M. Hassan; Hussam Mahmoud. Healthcare and education networks interaction as an indicator of social services stability following natural disasters. Scientific Reports 2021, 11, 1 -15.
AMA StyleEmad M. Hassan, Hussam Mahmoud. Healthcare and education networks interaction as an indicator of social services stability following natural disasters. Scientific Reports. 2021; 11 (1):1-15.
Chicago/Turabian StyleEmad M. Hassan; Hussam Mahmoud. 2021. "Healthcare and education networks interaction as an indicator of social services stability following natural disasters." Scientific Reports 11, no. 1: 1-15.
The use of machine learning has grown in popularity in various disciplines. Despite the popularity, the apparent ‘black box’ nature of such tools continues to be an area of concern. In this article, we attempt to unravel the complexity of this black box by exploring the use of artificial neural networks (ANNs), coupled with graph theory, to model and interpret the spatial distribution of building damage from extreme wind events at a community level. Structural wind damage is a topic that is mostly well understood for how wind pressure translates to extreme loading on a structure, how debris can affect that loading and how specific social characteristics contribute to the overall population vulnerability. While these themes are widely accepted, they have proven difficult to model in a cohesive manner, which has led primarily to physical damage models considering wind loading only as it relates to structural capacity. We take advantage of this modelling difficulty to reflect on two different ANN models for predicting the spatial distribution of structural damage due to wind loading. Through graph theory analysis, we study the internal patterns of the apparent black box of artificial intelligence of the models and show that social parameters are key to predict structural damage.
Stephanie F. Pilkington; Hussam N. Mahmoud. Interpreting the socio-technical interactions within a wind damage–artificial neural network model for community resilience. Royal Society Open Science 2020, 7, 200922 .
AMA StyleStephanie F. Pilkington, Hussam N. Mahmoud. Interpreting the socio-technical interactions within a wind damage–artificial neural network model for community resilience. Royal Society Open Science. 2020; 7 (11):200922.
Chicago/Turabian StyleStephanie F. Pilkington; Hussam N. Mahmoud. 2020. "Interpreting the socio-technical interactions within a wind damage–artificial neural network model for community resilience." Royal Society Open Science 7, no. 11: 200922.
Natural disasters may have catastrophic and long‐lasting impacts on communities' physical, economic, and social infrastructure. Slow recovery of educational services following such events is likely to cause traumatic stress in children, lead families to out‐migrate, and affect the community's overall social stability. Methods for quantifying and assessing the restoration process of educational systems and their dependencies on other supporting infrastructure have not received adequate attention. This study introduces, for the first time, a new framework to evaluate the functionality, recovery, and resilience of a school system following severe earthquake events. The framework considers both the quantity and quality of education services provided, school enrollment, and staff employment, as well as the interaction between various agents such as staff, students, parents, administration, and community. A virtual testbed community, Centerville, is utilized to highlight the application of this framework. The impact of school reopening policies on the number of students enrolled as well as the potential for homeschooling is also considered. The availability of various enrollment alternatives for students, backup classroom space and functioning utility systems, and facilitation of staff and supplies transfer between schools substantially increase the resilience of the education service.
Emad M. Hassan; Hussam N. Mahmoud; Bruce R. Ellingwood. Resilience of School Systems Following Severe Earthquakes. Earth's Future 2020, 8, 1 .
AMA StyleEmad M. Hassan, Hussam N. Mahmoud, Bruce R. Ellingwood. Resilience of School Systems Following Severe Earthquakes. Earth's Future. 2020; 8 (10):1.
Chicago/Turabian StyleEmad M. Hassan; Hussam N. Mahmoud; Bruce R. Ellingwood. 2020. "Resilience of School Systems Following Severe Earthquakes." Earth's Future 8, no. 10: 1.
Recent wildfire events, in the United States (USA) and around the world, have resulted in thousands of homes destroyed and many lives lost, leaving communities and policy makers, once again, with the question as to how to manage wildfire risk. This is particularly important given the prevalent trend of increased fire frequency and intensity. Current approaches to managing wildfires focus on fire suppression and managing fuel build-up in wildlands. However, reliance on these strategies alone has clearly proven inadequate. As such, focus should be shifted towards minimizing potential losses to communities. Achieving this goal, however, requires detailed understanding of the factors that contribute to community vulnerability and the interplay between probability of ignition, vulnerability and calculated risk. In this study, we evaluate wildfire risk for four different communities across the USA for the duration of May to September to communicate a different perspective of risk assessment. We show, for the first time, that community risk is closely related to wind speed and direction, pattern of surrounding wildland vegetation, and buildings layout. The importance of the findings lies in the need for exploring unique viable solutions to reduce risk for every community independently as opposed to embracing a generalized approach as is currently the case.
Hussam Mahmoud; Akshat Chulahwat. Assessing wildland–urban interface fire risk. Royal Society Open Science 2020, 7, 1 .
AMA StyleHussam Mahmoud, Akshat Chulahwat. Assessing wildland–urban interface fire risk. Royal Society Open Science. 2020; 7 (8):1.
Chicago/Turabian StyleHussam Mahmoud; Akshat Chulahwat. 2020. "Assessing wildland–urban interface fire risk." Royal Society Open Science 7, no. 8: 1.
In a seismic event, large number of aftershocks are generally triggered due to the complex interaction within and between tectonic plates. Even though aftershocks are typically smaller in magnitude than mainshocks, their ground-motion intensity, measured by peak ground acceleration, is not always smaller. Moreover, mainshocks can result in permanent damage to structural components. As a result, the vulnerability of structures to extensive damage and complete collapse due to aftershocks could increase. Despite their importance in evaluating the true risk of system failure and collapse, the inclusion of aftershocks in code provisions and guidelines for seismic risk assessment and performance-based engineering is lacking. In this study, three semi-rigid frames, with connection capacities of 50%, 60%, and 70% of the plastic moment of the beam, were designed and their performance under mainshock-aftershock sequences assessed. The objective of this study, pertaining to the seismic performance of the frames, is twofold. First, is to develop fragility functions for the subject frames under sequential mainshock-aftershock events. Second, is to evaluate the extent of spread of inelasticity and period elongation in the investigated frames as a result of the sequential events. A new method for selection and scaling of mainshock-aftershock sequences is proposed and non-linear time history analysis of the frames is conducted. The results show that the inclusion of the aftershocks increases the probability of reaching or exceeding a particular damage limit state in the frames, primarily due to the considerable period elongation resulting from the induced permanent damages.
Emad M. Hassan; Sushant Admuthe; Hussam Mahmoud. Response of semi-rigid steel frames to sequential earthquakes. Journal of Constructional Steel Research 2020, 173, 106272 .
AMA StyleEmad M. Hassan, Sushant Admuthe, Hussam Mahmoud. Response of semi-rigid steel frames to sequential earthquakes. Journal of Constructional Steel Research. 2020; 173 ():106272.
Chicago/Turabian StyleEmad M. Hassan; Sushant Admuthe; Hussam Mahmoud. 2020. "Response of semi-rigid steel frames to sequential earthquakes." Journal of Constructional Steel Research 173, no. : 106272.
Light-frame wood building construction dominates the single-family residential home market in the United States. Such buildings are susceptible to damage from extreme winds due to hurricanes in coastal areas and tornados in the Midwest. The consequences of extreme winds on the built environment and on social and economic institutions within the community can be severe and are likely to increase in the coming decades as a result of increases in urbanization and economic development and the potential impacts of changing climate in hazard prone areas. Current building practices provide minimum standards for occupant safety and health, including structural integrity, water and sanitation, lighting, ventilation, means of egress and fire protection. However, they generally do not consider building resilience, which includes robustness and an ability to recover following extreme natural hazard events. Nor do they address sustainability, the notion that building design, construction and rehabilitation should not adversely impact the environment. In this paper, we establish a generalized cost and carbon footprint life-cycle analysis methodology for examining the benefits of different building practices for residential light-frame wood construction subjected to tornado hazards. A multi-objective approach is used to reveal tradeoffs between resilient and sustainable practices for typical residential construction. We show that when the life cycle of a typical residence is considered, a balance between resilience, sustainability and cost might be achieved in design and rehabilitation of residential building construction for tornado hazards.
Pramodit Adhikari; Hussam N. Mahmoud; Aiwen Xie; Kathrina Simonen; Bruce R. Ellingwood. Life-cycle cost and carbon footprint analysis for light-framed residential buildings subjected to tornado hazard. Journal of Building Engineering 2020, 32, 101657 .
AMA StylePramodit Adhikari, Hussam N. Mahmoud, Aiwen Xie, Kathrina Simonen, Bruce R. Ellingwood. Life-cycle cost and carbon footprint analysis for light-framed residential buildings subjected to tornado hazard. Journal of Building Engineering. 2020; 32 ():101657.
Chicago/Turabian StylePramodit Adhikari; Hussam N. Mahmoud; Aiwen Xie; Kathrina Simonen; Bruce R. Ellingwood. 2020. "Life-cycle cost and carbon footprint analysis for light-framed residential buildings subjected to tornado hazard." Journal of Building Engineering 32, no. : 101657.
The risk of overwhelming healthcare systems from a second wave of COVID-19 is yet to be quantified. Here, we investigate the impact of different reopening scenarios of states around the U.S. on COVID-19 hospitalized cases and the risk of overwhelming the healthcare system while considering resources at the county level. We show that the second wave might involve an unprecedented impact on the healthcare system if an increasing number of the population becomes susceptible and/or if the various protective measures are discontinued. Furthermore, we explore the ability of different mitigation strategies in providing considerable relief to the healthcare system. The results can aid healthcare planners, policymakers, and state officials in making decisions on additional resources required and on when to return to normalcy.One Sentence SummaryA second wave of COVID-19 will have an unprecedented impact on the healthcare system.
Emad M. Hassan; Hussam Mahmoud. Impact of COVID-19 Second Wave on Healthcare Networks in the United States. 2020, 1 .
AMA StyleEmad M. Hassan, Hussam Mahmoud. Impact of COVID-19 Second Wave on Healthcare Networks in the United States. . 2020; ():1.
Chicago/Turabian StyleEmad M. Hassan; Hussam Mahmoud. 2020. "Impact of COVID-19 Second Wave on Healthcare Networks in the United States." , no. : 1.
The premise of community resilience hinges on preventing extreme events from becoming disasters through minimizing initial disruptions and ensuring quick recovery of the various community sectors. Recovery of critical facilities and public assemblies, such as the healthcare systems, is particularly important since they are vital for short-term and long-term functioning of communities. This article outlines a new framework for estimating full functionality and recovery of healthcare systems in a community following earthquake occurrence. The presented framework includes estimation of both quantity and quality components of the offered healthcare service overtime and quantification of patient demand on each healthcare facility while accounting for their interdependence as well as their interaction with other community infrastructure. When estimating the recovery of healthcare services, stochastic modeling and dynamic optimization are utilized to account for limited repair resources, repair sequences, and change in demand over time. The presented approach is applied to Centerville, a virtual testbed community, to highlight the capabilities of the proposed framework and the impact of decisions made on the recovery trajectory. It is observed that high level of interaction between the healthcare system components is essential to reduce patient demands on hospitals. It is also shown that proper allocation and distribution of repair resources are key to achieving the desired level of functionality for the hospitals.
Emad M. Hassan; Hussam Mahmoud. An integrated socio-technical approach for post-earthquake recovery of interdependent healthcare system. Reliability Engineering & System Safety 2020, 201, 106953 .
AMA StyleEmad M. Hassan, Hussam Mahmoud. An integrated socio-technical approach for post-earthquake recovery of interdependent healthcare system. Reliability Engineering & System Safety. 2020; 201 ():106953.
Chicago/Turabian StyleEmad M. Hassan; Hussam Mahmoud. 2020. "An integrated socio-technical approach for post-earthquake recovery of interdependent healthcare system." Reliability Engineering & System Safety 201, no. : 106953.
The direct physical loss from a tornado is one possible factor in considering resilience goals for a community. Estimating such loss has historically been achieved either through analysis of empirical data from historical events meant to then match future hypothetical events or through a cost analysis based on a building's damage state. These approaches provide a solid baseline for estimating loss from wind events; however, gathering data from historical events may assume all locations are the same, while analyses based solely on the building damage state may not include a building's contents. This study builds on work previously established in determining loss from building damage state fragilities, by including a loss to the building's interior (including contents) based on Federal Emergency Management Agency's (FEMA's) HAZUS equations. The approach laid out in this paper is then validated, showing what is deemed an acceptable level of accuracy, using the May 22, 2011 Joplin tornado that devastated the local community. Once validated, the same tornado path is relocated in different directions, ultimately crossing most of city of Joplin in four additional hypothetical scenarios. The results of both hindcasting the 2011 Joplin tornado and its hypothetical track variations show commercial (nonresidential) type buildings as key in contributing to the direct physical loss of a wind event. Ultimately, this provides decision makers with a point of consideration when evaluating their community's resilience goals.
Stephanie F. Pilkington; Hussam N. Mahmoud; John W. Van De Lindt; Maria Koliou; Steve Smith. Hindcasting Loss and Evaluating Implications of Track Location for the 2011 Joplin, Missouri Tornado. ASCE-ASME J Risk and Uncert in Engrg Sys Part B Mech Engrg 2020, 6, 1 .
AMA StyleStephanie F. Pilkington, Hussam N. Mahmoud, John W. Van De Lindt, Maria Koliou, Steve Smith. Hindcasting Loss and Evaluating Implications of Track Location for the 2011 Joplin, Missouri Tornado. ASCE-ASME J Risk and Uncert in Engrg Sys Part B Mech Engrg. 2020; 6 (2):1.
Chicago/Turabian StyleStephanie F. Pilkington; Hussam N. Mahmoud; John W. Van De Lindt; Maria Koliou; Steve Smith. 2020. "Hindcasting Loss and Evaluating Implications of Track Location for the 2011 Joplin, Missouri Tornado." ASCE-ASME J Risk and Uncert in Engrg Sys Part B Mech Engrg 6, no. 2: 1.
Flood risk to urban communities is increasing significantly as a result of the integrated effects of climate change and socio‐economic development. The latter effect is one of the main drivers of rising flood risk has received less attention in comparison to climate change. Economic development and population growth are major causes of urban expansion in flood‐prone areas, and a comprehensive understanding of the impact of urban growth on flood risk is an essential ingredient of effective flood risk management. At the same time, planning for community resilience has become a national and worldwide imperative in recent years. Enhancements to community resilience require well‐integrated and enormous long‐term public and private investments. Accordingly, comprehensive urban growth plans should take rising flood risk into account to ensure future resilient communities through careful collaboration between engineers, geologists, socialists, economists, and urban planners within the framework of life‐cycle analysis. This paper highlights the importance of including urban growth in accurate future flood risk assessment and how planning for future urbanization should include measurement science‐based strategies in developing policies to achieve more resilient communities.
Mona Hemmati; Bruce R. Ellingwood; Hussam N. Mahmoud. The Role of Urban Growth in Resilience of Communities Under Flood Risk. Earth's Future 2020, 8, 1 .
AMA StyleMona Hemmati, Bruce R. Ellingwood, Hussam N. Mahmoud. The Role of Urban Growth in Resilience of Communities Under Flood Risk. Earth's Future. 2020; 8 (3):1.
Chicago/Turabian StyleMona Hemmati; Bruce R. Ellingwood; Hussam N. Mahmoud. 2020. "The Role of Urban Growth in Resilience of Communities Under Flood Risk." Earth's Future 8, no. 3: 1.
Terrorism has become a major challenge for the world. Terrorist organizations have raised their activities and their attacks in the last years using explosives. These attacks have left numerous numbers of victims, wreaked massive havoc to basic infrastructure, and increased global concern about the nature of these attacks. Blast wall protection systems can provide a required safety level to reduce injuries/casualties in different attack scenarios. Furthermore, installation and procurement costs could be greatly reduced using readily available materials. This paper investigates the performance of a composite wood-sand-wood blast wall by estimating the probability of exceeding a performance limit state for the wall for a suicide vest threat scenario. Fragility curves were devised using direct Monte Carlo simulations to predict the probability of failure of an equivalent simplified single degree-of-freedom system. The simplified model, calibrated to a 3D finite element analysis of the prototype wall, was used to determine the horizontal displacement at the back center of the wall. The analysis framework was developed to probabilistically evaluate the performance of the proposed blast wall in the presence of uncertainties in structural properties and blast load parameters under increasing intensity of the blast. Uncertainties in the random variables were modeled using appropriate statistical distributions. The analyses results show that under certain conditions the wall can provide the required level of protection for the considered threat scenarios.
Assal Hussein; Hussam Mahmoud; Paul Heyliger. Probabilistic analysis of a simple composite blast protection wall system. Engineering Structures 2019, 203, 109836 .
AMA StyleAssal Hussein, Hussam Mahmoud, Paul Heyliger. Probabilistic analysis of a simple composite blast protection wall system. Engineering Structures. 2019; 203 ():109836.
Chicago/Turabian StyleAssal Hussein; Hussam Mahmoud; Paul Heyliger. 2019. "Probabilistic analysis of a simple composite blast protection wall system." Engineering Structures 203, no. : 109836.
Bridges in America are aging and deteriorating, causing substantial financial strain on federal resources and tax payers' money. Of the various deterioration issues in bridges, one of the most common and costly is malfunctioning of expansion joints, connecting two bridge spans, due to accumulation of debris and dirt in the joint. Although expansion joints are small components of bridges' superstructure, their malfunction can result in major structural problems and when coupled with thermal stresses, the demand on the structural elements could be further amplified. Intuitively, these additional demands are expected to even worsen if one considers potential future temperature rise due to climate change. Indeed, it has been speculated that climate change is likely to have negative effect on bridges worldwide. However, to date there has been no serious attempts to quantify this effect on a larger spatial scale with no studies pertaining to the integrity of the main load carrying girders. In this study, we attempt to quantify the effect of clogged joints and climate change on failure of the superstructure of a class of steel bridges around the U.S. We surprisingly find that potentially most of the main load carrying girders, in the analyzed bridges, could reach their ultimate capacity when subjected to service load and future climate changes. We further discover that out of nine U.S. regions, the most vulnerable bridges, in a descending order, are those located in the Northern Rockies & Plains, Northwest and Upper Midwest. Ultimately, this study proposes an approach to establish a priority order of bridge maintenance and repair to manage limited funding among a vast inventory in an era of climate change.
Susan Palu; Hussam Mahmoud. Impact of climate change on the integrity of the superstructure of deteriorated U.S. bridges. PLOS ONE 2019, 14, e0223307 .
AMA StyleSusan Palu, Hussam Mahmoud. Impact of climate change on the integrity of the superstructure of deteriorated U.S. bridges. PLOS ONE. 2019; 14 (10):e0223307.
Chicago/Turabian StyleSusan Palu; Hussam Mahmoud. 2019. "Impact of climate change on the integrity of the superstructure of deteriorated U.S. bridges." PLOS ONE 14, no. 10: e0223307.
Modeling the recovery process of a community’s infrastructure after the occurrence of extreme events is now at the forefront of research. Estimating post-disaster recovery of either single or multiple infrastructure in a community requires proper flow and interaction of information of the physical, economic and social components of the involved sectors. Understanding this recovery process is essential, particularly for critical infrastructure, such as a hospital, which is vital for a community’s well-being. In this study, the full seismic functionality and recovery process of a six-story hospital, located in Memphis, TN, is quantified and assessed using a comprehensive 3-D finite element model with soil-structure interaction. The hospital functionality assessment encompasses both the quantity and the quality of the hospitalization service. To account for hospital dependency on other infrastructure during the recovery process, a virtual community is assumed, and five additional lifelines are included in the analysis. The model accounts for limitation in resources within the community, expected economic return for each lifeline, and interdependencies between the different lifelines. The introduced framework is implemented using data gathered from historical earthquakes as well as assumed data as needed. Recoveries of the different lifelines are estimated using continuous Markov chain process, where the community resources are distributed among the different lifelines using dynamic optimization to either obtain the most economic return for the whole community or the fastest recovery of the hospital. In addition, the effect of including infrastrcture interdependence on the recovery of the hospital is evaluated. The results are further utilized to estimate the seismic resilience of the hospital.
Emad M. Hassan; Hussam Mahmoud. Full functionality and recovery assessment framework for a hospital subjected to a scenario earthquake event. Engineering Structures 2019, 188, 165 -177.
AMA StyleEmad M. Hassan, Hussam Mahmoud. Full functionality and recovery assessment framework for a hospital subjected to a scenario earthquake event. Engineering Structures. 2019; 188 ():165-177.
Chicago/Turabian StyleEmad M. Hassan; Hussam Mahmoud. 2019. "Full functionality and recovery assessment framework for a hospital subjected to a scenario earthquake event." Engineering Structures 188, no. : 165-177.
Bridge expansion joints are a particularly troublesome component of bridges, and many DOTs are seeking maintenance solutions for deteriorating expansion joints. Bridge expansion joints create a break in the structural continuity of a bridge, allowing clogging gravels and corroding chlorides to enter. To prevent deterioration of other bridge elements, the joints must be cleaned regularly and replaced promptly after failure. Unfortunately, limited time and resources hinder most DOTs from properly maintaining expansion joints, which eventually leads to deterioration of bridge elements. To reduce maintenance problems, some DOTs have started to move away from the practice of repeatedly replacing the joints upon failure in favor of retrofitting bridges to remove joints altogether. Life cycle cost analysis (LCCA) provides a formal way to compare alternative approaches for dealing with bridge expansion joints. This paper presents an LCCA for existing bridge expansion joint alternatives, including the practices of routine joint replacement and removal of joints. Three different cost scenarios are considered, including the consequences of leaking expansion joints. All scenarios indicate that the removal of all bridge expansion joints in favor of a continuous bridge deck is a cost-effective maintenance solution.
Aura Lee Kelly; Rebecca A. Atadero; Hussam N. Mahmoud. Life Cycle Cost Analysis of Deteriorated Bridge Expansion Joints. Practice Periodical on Structural Design and Construction 2019, 24, 04018033 .
AMA StyleAura Lee Kelly, Rebecca A. Atadero, Hussam N. Mahmoud. Life Cycle Cost Analysis of Deteriorated Bridge Expansion Joints. Practice Periodical on Structural Design and Construction. 2019; 24 (1):04018033.
Chicago/Turabian StyleAura Lee Kelly; Rebecca A. Atadero; Hussam N. Mahmoud. 2019. "Life Cycle Cost Analysis of Deteriorated Bridge Expansion Joints." Practice Periodical on Structural Design and Construction 24, no. 1: 04018033.