Wael El-Dakhakhni

McMaster University | McMaster · Department of Civil Engineering

This study presents an enhanced predictive model for the seismic shear strength of exterior beam-column joints (BCJs). Initially, the principles of strut-and-tie mechanism and variable selection procedures were first utilized to identify the most influential parameters. Subsequently, an evolutionary algorithm, specifically multigene genetic program...

During seismic events, reinforced concrete (RC) columns play a crucial role in maintaining buildings’ structural integrity. This motivated engineers and practitioners to search for key parameters that influence the load-carrying capacity and failure mechanisms of such columns. However, the complexity and nonlinearity of seismic effects along with t...

Unbonded post-tensioned concrete masonry (UPCM) shear walls present an effective seismic force resisting system due to their ability to mitigate expected damage risks through their self-centering capabilities. A few design procedures were proposed to predict the in-plane flexural response of UPCM walls, albeit following only basic mechanics and/or...

A number of regression-based models have been proposed to quantify the seismic shear strength of reinforced concrete (RC) columns. However, most of these models suffer from a high degree of uncertainty as a result of the limited datasets used in their development and/or the classic approaches used to capture the non-linear interrelationships betwee...

Climate change and a growing global population pose ongoing threats to critical resources. As resources required by the agriculture sector continue to diminish, it is critical to leverage the emerging technologies and new solutions within the sector. New cultivation practices have emerged over the years, allowing food to be grown within urban areas...

The growing global population and climate change threaten the availability of many critical resources, and have been directly impacting the food and agriculture sector. Therefore, new cultivation technologies must be rapidly developed and implemented to secure the world's future food needs. Closed-loop greenhouse agriculture systems provide an oppo...

Dynamic probabilistic risk assessment (DPRA) of nuclear power plants (NPPs) has become one of the most critical research areas, especially in the aftermath of the 2011 Fukushima Daiichi nuclear accident. Uncertainty in NPP behavior is key when considering its safety under different operating conditions. Such uncertainty typically results from opera...

The recent advances in artificial intelligence have led to the rapid development of computer-aided skin cancer diagnosis applications that perform on par with dermatologists. However, the black-box nature of such applications makes it difficult for physicians to trust the predicted decisions, subsequently preventing the proliferation of such applic...

In the last decade, injury statistics have not exhibited appreciable improvement within the construction industry, with current management strategies deployed reactively in response to typically safety lagging indicators (e.g., injury rates, lost workdays, and post-incident inspections). This situation suggests that proactive safety management appr...

The frequency of climate-induced disasters (CID) has exhibited a fivefold increase in the last five decades. In terms of CID global impact, around 1.7 billion people were affected in the last decade, and in 2020 alone, 30 million people were displaced due to CID. Furthermore, over the past two decades, 1 million deaths were reported and over $1.7 t...

A growing global population and climate change threaten the availability of many critical resources, and they are directly impacting the food and agriculture sector. Therefore, new cultivation technologies must be rapidly adopted and implemented to secure the world’s food needs. Closed-loop greenhouse agriculture systems provide an opportunity to d...

The Earth's subsurface consists of porous media (i.e., rocks, soils) with vastly varied internal structures and properties. Characterizing the physical properties of porous media is an important activity for geologists, geotechnical, structural, environmental, and petroleum engineers. For instance, porous media's fluid flow properties are essential...

The amount of data accumulated by utility companies is growing in volume and variety each year. Such data can be a very valuable asset to utilities, but because it is generally viewed only through traditional tables and charts, it has not yet been used to its full potential. A utility can make better use of its data by employing machine learning te...

In the past decades, the United States of America and Canada have witnessed a continuous increase in the frequency and magnitude of climate change-induced natural disasters. These events include droughts, floods, wildfires, and most recently, tornadoes. In 2016, climate change induced damage was estimated to be $8.6 billion in Canada, while in the...

The southern Saskatchewan region has been recognized for persistent droughts due to its continual rainfall deficiency. To estimate drought severity, a first-order and five-state Markov chain model is used in this study. Long-term daily precipitation records of three stations (Broadview, Last Mountain CS, and Swift Current CDA) were considered for t...

Reinforced concrete block shear walls (RCBSWs) have been used as an effective seismic force resisting system in low- and medium-rise buildings for many decades. However, attributed to their complex nonlinear behavior and the composite nature of their constituent materials, accurate prediction of their seismic performance, relying solely on mechanic...

This study contributes to investigating the potential of using lightweight slag aggregates (SL) in structural applications, as well as exploring the near-optimal options of using fine and/or coarse SL to construct high-performance lightweight structural elements. Large-scale self-consolidating reinforced concrete beams were cast with different comb...

Bisphenol A (BPA) is one of the most common contaminants of emerging concerns (CECs), which pose a threat to human health. Conventional wastewater treatment plants (WWTPs) are considered as the major pathway of BPA entering the aqueous environment. To control and mitigate BPA contamination in the aquatic environment, predicting BPAs fate at WWTPs i...

Floods have been among the costliest hydrometeorological hazards across the globe for decades, and are expected to become even more frequent and cause larger devastating impacts in cities due to climate change. Digital twin technologies can provide decisionmakers with effective tools to rapidly evaluate city resilience under projected floods. Howev...

In this paper, a hybrid model is developed to simulate solute transport in discrete fracture networks (DFNs) considering mass exchange between the fracture and the surrounding matrix. The developed model considers three mechanisms: advection and dispersion along the fracture, molecular diffusion within the fracture and into the matrix, and adsorpti...

Increased severity and frequency of climate-induced disasters (CID) is affecting the resilience of cities worldwide. Canadian insurers are facing natural disaster-induced claims of approximately $1 billion annually, whereas it was closer to $400 million in the previous decade. Moreover, annual national liabilities of the Disaster Financial Assistan...

Complex by nature, infrastructure megaprojects rarely meet stakeholders' expectations. A key characteristic of such complexity is the interdependence among different project stakeholders (e.g., contractors) where disruption of one contractor's work may instigate (system-level) systemic risks, resulting in poor key performance indicators (KPIs) of t...

Background The lack of dark skin images in pathologic skin lesions in dermatology resources hinders the accurate diagnosis of skin lesions in people of color. Artificial intelligence applications have further disadvantaged people of color because those applications are mainly trained with light skin color images. Objective The aim of this study is...

Disruptions due to either natural or anthropogenic hazards can significantly impact the operation of critical infrastructure networks (e.g., transportation systems) as they may instigate network-level (cascade) systemic risks, thus impacting the overall city resilience. Recent relevant studies demonstrated the need to quantify the resilience of cit...

An effective infrastructure asset management (AM) system is crucial for utilities, city officers, government agencies, and other asset-owning organizations to facilitate navigating the numerous challenges associated with operating and managing infrastructure assets. In this paper, the AM system itself is represented as a complex network (comprised...

Despite the prevalence of bus transit networks in urban public transportation, they are very susceptible to disruptions that can have negative implications, accompanied by severe socioeconomic consequences and service quality consequences. In addition, since bus transit system is comprised of stops, routes, and passengers, any disruptions in the bu...

Climate change and the development of urban centers within flood-prone areas have significantly increased flood-related disasters worldwide. However, most flood risk categorization and prediction efforts have been focused on the hydrologic features of flood hazards, often not considering subsequent long-term losses and recovery trajectories (i.e.,...

The complexity of the shear buckling in tapered plate girders has motivated researchers to conduct experimental and numerical investigations to understand the underlying mechanisms controlling such phenomenon, and subsequently develop related design-oriented expressions. However, existing predictive models have been developed and validated using li...

Power infrastructure networks are susceptible to performance disruptions induced by natural or anthropogenic hazard events. Forexample, extreme weather events or cyberattacks can disrupt the functionality of multiple network components concurrently or sequentially,resulting in a chain of cascading failures throughout the network. Mitigating the imp...

Global warming has been observed for decades, and associated climate change is expected to increase the frequency of rare severe events. In Canada, floods are the costliest climate change-induced disasters. For example, the damage cost due to the 2013 flood in Calgary was around $5 billion. Similar devastating floods occurred in other Canadian regi...

Flood is one of the disastrous events in Canada, affecting both the sustenance of people and the country’s economy. A short-term flood warning system can be beneficial for small cities as it requires less data and helps different stakeholders to take preventive measures to lessen flood damages. This study developed a first-order Markovian model (MC...

With the increasing impact of climate change, the expansive urbanization within flood prone areas is causing a significant increase in flood-related disasters worldwide. In the past decades, the United States of America and Canada have witnessed a continuous increase in the frequency and magnitude of climate change-induced natural disasters. These...

Power infrastructure is essential for the operation of almost all other critical infrastructure systems, including water, transportation, and telecommunications. Recently, there has been an increase in forced power outage frequency and extent due to infrastructure aging, extreme weather events, and deliberate attacks. To combat forced power outage...

The rocking response of a freestanding rigid block depends on two parameters: its size and slenderness. In nuclear power plants, seismic qualification test reports for one component (the reference) can be utilized to seismically qualify another (the candidate) component by following item equivalency procedures based on form, fitness, and function o...

Subsurface characterization is critical in understanding and controlling many natural and industrial processes including groundwater movement, oil extraction, and geological carbon dioxide sequestration. While recent advances in three‐dimensional (3D) imaging of core samples have enabled digital subsurface characterization, the exorbitant computati...

The superior performance of steel fibers (SFs) in enhancing the shear capacity of reinforced concrete (RC) beams supports their use in regions that would otherwise require minimum shear reinforcement (stirrups). Subsequently, several researchers proposed different predictive models to capture the contribution of SFs to the shear capacity of RC beam...

The frequency and magnitude of Climate-Induced Disasters (CID) has been increasing consistently over the past few decades. Alleviating the impacts of such disasters is thus critically important. Hence, a systematic data-driven framework is developed to predict CID-related damages. The framework encompasses four phases: (1) Data Collection and Fusio...

The ever-increasing investment gap for deteriorating infrastructure has necessitated the development of more effective asset management (AM) strategies. However, information asymmetry among AM stakeholder silos has been recognized as a key challenge in implementing effective AM strategies. The connectivity within the AM system introduces systemic r...

Construction is a key pillar in the global economy, but it is also an industry that has one of the highest fatality rates. The goal of the current study is to employ machine learning in order to develop a framework based on which better-informed and interpretable injury-risk mitigation decisions can be made for construction sites. Central to the fr...

The importance of ensuring the resilience (rapid adaptation to and recovery from disruptions) of infrastructure projects in modern societies can be hardly overstated. However, relying solely on currently available tools, managing such projects continues to be challenging because of their intrinsic complexities and dynamic spatiotemporal interdepend...

We defined the concept of a common-knowledge network of authors in a research institution and used it to identify communities of authors using a new heuristic algorithm for clustering editing problem on weighted similarity measure networks. We analyzed the possible dominating research topics based on the most frequent keywords, publication and coll...

Continuous monitoring of wastewater treatment processes is key to mitigate the risk of inadequately treated wastewater on the environment and public health. However, effective control of wastewater treatment processes is challenging because of the numerous relevant variables and their complex physio-chemical-biological interdependence. Most publish...

The design provisions of current blast protection standards are primarily focused on the response of single components and do not provide adequate tools to quantify the overall performance of critical infrastructure systems (CIS), let alone the interdependence of such systems. Methodologies that can translate blast-induced damage into information a...

Hydropower dams are critical infrastructure systems characterized by their complex, dynamic, and stochastic behaviors. The frequent variation in the hydrological and meteorological variables poses a higher probability of dam failure, highlighting the need to improve pertinent risk assessment approaches to predict failure risks, considering the unce...

Hydropower dams are critical infrastructure systems characterized by their complex, dynamic, and stochastic behaviors. The frequent variation in the hydrological and meteorological variables poses a higher probability of dam failure, highlighting the need to improve pertinent risk assessment approaches to predict failure risks, considering the unce...

In lieu of process-based models, evolutionary artificial intelligence techniques can yield accurate expressions describing complex phenomena. In the current study, closed-form expressions are developed to predict solute transport in a fracture-matrix system as a function of the parameters that describe relevant physical and chemical processes. The...

Background: The paucity of dark skin images in dermatological textbooks and atlases is a reflection of racial injustice in medicine. The underrepresentation of dark skin images makes diagnosing skin pathology in people of color challenging. In conditions when early diagnosis makes a difference between life and death, such as skin cancer, people of...

BACKGROUND The paucity of dark skin images in dermatological textbooks and atlases is a reflection of racial injustice in medicine. The underrepresentation of dark skin images makes diagnosing skin pathology in people of color challenging. For conditions such as skin cancer, in which early diagnosis makes a difference between life and death, people...

A computationally efficient analytical network (AN) model simulating solute transport in discrete fracture networks (DFNs) is developed. The model simulates two-dimensional spatial and temporal distribution of a solute considering advection and hydrodynamic dispersion within the fractures, matrix diffusion, sorption onto the fracture walls and in t...

Power infrastructure networks continue to be at risk under natural and anthropogenic hazard events. Cyberattacks targeting power grids aim at magnifying the impacts through damage propagation to other dependent infrastructure network. In this respect, the current study focuses on the “draw-down” phase of power infrastructure network resilience cons...

The failure of uranium mine tailings dams results in the infiltration and spreading of tailings in the subsurface. The fate and transport of radionuclides in the subsurface depends on several confounding, complex interdependent factors that describe the elements of the integrated system (i.e., meteorological; hydrological; hydrogeological; and, soi...

The current blast response limits for reinforced masonry (RM) walls in North American blast standards are based on parameters that neither account for the wall ductility capacities nor the influence of different design configurations on the wall damage tolerance levels. Specifically, ASCE (2011) and CSA (2012) currently assign a support chord rotat...

Although highway bridges are among the most critical components in transportation infrastructure systems, different jurisdictions typically allocate only limited annual budgets to address issues pertaining to aging and deteriorating bridges. In addition, most published studies have focused only on component-by-component risk analysis (i.e., risk of...

Coupled with climate change, the expansive developments of urban areas are causing a significant increase in flood-related disasters worldwide. However, most flood risk analysis and categorization efforts have been focused on the hydrologic features of flood hazards (e.g., inundation depth, extent, and duration), rarely considering the resulting lo...

Decentralized decision-making is becoming more ubiquitous in different organizations that often follow a hierarchical structure. To model these problems, multi-level programming has been suggested as a suitable methodology for modeling the interaction between the different levels of decisions. However, multi-level programming, even for the case of...

The amount of data accumulated by utility companies is growing in volume and variety each year. Such data can be a very valuable asset to utilities, but because it is generally viewed only through traditional tables and charts, it has not yet been used to its full potential. A utility can make better use of its data by employing machine learning te...

Rapid or unexpected bridge deterioration can lead to partial collapse, which can subsequently hinder transportation activities and result in economic and human losses. Heavily adopted by the research community, Markov chain-based deterioration models assume that bridge conditions exhibit stationary transitions over time. This assumption requires a...

Global warming has been observed for decades, and associated climate change is expected to increase the frequency of rare severe events. In Canada, floods are the costliest climate change-induced disasters. For example, the damage cost due to the 2013 flood in Calgary was around $5 billion. Similar devastating floods occurred in other Canadian regi...

In the past decades, the United States of America and Canada have witnessed a continuous increase in the frequency and magnitude of climate change-induced natural disasters. These events include droughts, floods, wildfires, and most recently, tornadoes. In 2016, climate change induced damage was estimated to be $8.6 billion in Canada, while in the...

Although boundary elements have been demonstrated to enhance the in-plane performance of reinforced concrete block shear walls under seismic loading, research evaluating their effect on the walls' out-of-plane performance (e.g., due to earth pressure, wind loading, or blast loading) is very scarce. As such, current blast standards do not assign uni...

The increased severity and frequency of Climate-Induced Disasters (CID) including those attributed to hydrological, meteorological, and climatological effects have been testing the resilience of cities worldwide. The World Economic Forum highlighted—in its 2020 Global Risk Report—that from 2018 to 2020, three of the top five risks with respect to l...

The implication of optimal low impact development (LID) implementations has been attracting researchers' attention, aiming to alleviate the detrimental impacts of urbanization and climate change and enhance resilience. The increasing number of publications on LID optimization over the recent years makes it one of the leading-edge research areas in...

A Nuclear Power Plant (NPP) is a complex dynamic system-of-systems with highly nonlinear behaviors. In order to control the plant operation under both normal and abnormal conditions, different systems in NPPs (e.g., the reactor core components, primary and secondary coolant systems) are usually monitored continuously, resulting in very large amount...

The increases in accidental explosion events over the past two decades have demonstrated the urgent need to evaluate the behavior of blast-vulnerable structural components and develop subsequent risk mitigation strategies. In this context, several studies have focused on the out-of-plane behavior of either unreinforced masonry walls or non-load bea...

Subsurface fluid flow prediction is critical in many natural and industrial processes such as groundwater movement, oil extraction, and geological carbon dioxide sequestration. These processes are controlled by the permeability of the underground porous media (i.e., soil, rock, etc.). Traditionally, the permeability of porous media is determined vi...

The Earth's subsurface consists of porous media (i.e., rocks, soils) with vastly varied internal structures and properties. Characterizing the physical properties of porous media is an important activity for geologists, geotechnical, structural, environmental, and petroleum engineers. For instance, porous media's fluid flow properties are essential...

Reinforced masonry shear wall (RMSW) systems constructed using concrete blocks are widely used within the current North American construction practices. The limited research carried out on the performance of RMSWs under blast loading has reviled their high vulnerability. This study evaluates the blast performance of such loadbearing and non-loadbea...

Subsurface fluid flow prediction is critical in many natural and industrial processes such as ‎groundwater ‎movement, oil extraction, and geological carbon dioxide sequestration. These processes ‎are controlled by ‎the permeability of the underground porous media (i.e., soil, rock, etc.). ‎Traditionally, the permeability of ‎porous media is determi...

The frequency of Climate-induced Disasters (CID) has tripled in the last three decades, driving the World Economic Forum to identify them as the most likely and most impactful risks worldwide. With more than 70% of the world population expected to be living in cities by 2050, ensuring the resilience of urban infrastructure systems under CID is cruc...

Several approaches are commonly applied to modeling fractured aquifers, including stochastic continuum (SC) and discrete fracture network (DFN) models. While DFN models provide a more realistic representation of the system, their development necessitates an accurate characterization of the fracture network. Extensive, and often prohibitive, resourc...

Objectives Irreversible colloid deposition in groundwater-saturated fractures is typically modeled using a lumped deposition coefficient (κ) that reflects the system physiochemical conditions. A mathematical relationship between this coefficient and the physicochemical conditions controlling deposition has not yet been defined in the literature; th...

The performance of nonstructural components in nuclear power plants (NPPs), which is primarily based on experience and historical data, has been attracting increased interest from researchers following the Fukushima Daiichi nuclear disaster in 2011. This disaster demonstrated the importance of using batteries in NPPs as an auxiliary power system, w...

Squat reinforced concrete shear walls with boundary elements (SRCSW-BE) are used in special structures (e.g., nuclear facilities) to resist lateral seismic loads. However, several studies have demonstrated the inaccuracy of the relevant current shear strength prediction expressions (e.g., ASCE/SEI 43-05). Specifically, expressions originally develo...

Given the unforeseen events that take continue to place worldwide, cities are experiencing rapid transformations. To maintain their basic functions, cities have to be resilient– possess the ability to bounce back to their original state following extreme events. Unfortunately, the behavior of cities is complex because of the interdependence among t...