Habibnezhad, M.; Puckett, J.; Fardhosseini, M.S.; Jebelli, H.; Stentz, T.; Pratama, L.A.. (2019). Experiencing Extreme Height for the First Time: The Influence of Height, Self-Judgment of Fear and a Moving Structural Beam on the Heart Rate and Postural Sway During the Quiet Stance. Arxiv, 9 pp.
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Abstract
Falling from elevated surfaces is the main cause of death and injury at construction sites. Based on the Bureau of Labor Statistics (BLS) reports, an average of nearly three workers per day suffer fatal injuries from falling. Studies show that postural instability is the foremost cause of this disproportional falling rate. To study what affects the postural stability of construction workers, we conducted a series of experiments in the virtual reality (VR). Twelve healthy adults, all students at the University of Nebraska were recruited for this study. During each trial, participants heart rates and postural sways were measured as the dependent factors. The independent factors included a moving structural beam (MB) coming directly at the participants, the presence of VR, height, the participants self-judgment of fear, and their level of acrophobia. The former was designed in an attempt to simulate some part of the steel erection procedure, which is one of the key tasks of ironworkers. The results of this study indicate that height increase the postural sway. Self-judged fear significantly was found to decrease postural sway, more specifically the normalized total excursion of the center of pressure (TE), both in the presence and absence of height. Also, participants heart rates significantly increase once they are confronted by a moving beam in the virtual environment (VE), even though they are informed that the beam will not hit them. The findings of this study can be useful for training novice ironworkers that will be subjected to height and steel erection for the first time.
Keywords
Biocontrol; Biomechanics; Construction Industry; Ergonomics; Injuries; Mechanoception; Medical Computing; Occupational Safety; Personnel; Statistical Analysis; Virtual Reality; Extreme Height; Moving Structural Beam; Heart Rate; Postural Sway; Injury; Construction Sites; Labor Statistics Reports; Fatal Injuries; Postural Instability; Foremost Cause; Disproportional Falling Rate; Postural Stability; Construction Workers; Participants Heart Rates; Height Increase; Moving Beam
Habibnezhad, M.; Puckett, J.; Fardhosseini, M.S.; Pratama, L.A. (2019). A Mixed VR and Physical Framework to Evaluate Impacts of Virtual Legs and Elevated Narrow Working Space on Construction Workers Gait Pattern. Arxiv, 7 pp.
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Abstract
It is difficult to conduct training and evaluate workers' postural performance by using the actual job site environment due to safety concerns. Virtual reality (VR) provides an alternative to create immersive working environments without significant safety concerns. Working on elevated surfaces is a dangerous scenario, which may lead to gait and postural instability and, consequently, a serious fall. Previous studies showed that VR is a promising tool for measuring the impact of height on the postural sway. However, most of these studies used the treadmill as the walking locomotion apparatus in a virtual environment (VE). This paper was focused on natural walking locomotion to reduce the inherent postural perturbations of VR devices. To investigate the impact of virtual height on gait characteristics and keep the level of realism and feeling of presence at their highest, we enhanced the first-person-character model with "virtual legs". Afterward, we investigated its effect on the gait parameters of the participants with and without the presence of height. To that end, twelve healthy adults were asked to walk on a virtual loop path once at the ground level and once at the 17th floor of an unfinished structure. By quantitatively comparing the participants' gait pattern results, we observed a decrease in the stride length and increase in the gait duration of the participants exposed to height. At the ground level, the use of the enhanced model reduced participants' average stride length and height. The results of this study help us understand users' behaviors when they were exposed to elevated surfaces and establish a firm ground for gait stability analysis for the future height-related VR studies. We expect this developed VR platform can generate reliable results of VR application in more construction safety studies.
Keywords
Civil Engineering Computing; Construction Industry; Gait Analysis; Medical Computing; Occupational Safety; Virtual Reality; Construction Safety Studies; Mixed Vr; Virtual Legs; Construction Workers Gait Pattern; Immersive Working Environments; Postural Instability; Serious Fall; Postural Sway; Walking Locomotion Apparatus; Natural Walking Locomotion; Inherent Postural Perturbations; Vr Devices; Virtual Height; First-person-character Model; Gait Parameters; Virtual Loop Path; Stride Length; Gait Duration; Gait Stability Analysis; Safety Concerns; Vr Platform; Height-related Vr Studies
Gomez-Cunya, Luis-Angel; Fardhosseini, Mohammad Sadra; Lee, Hyun Woo; Choi, Kunhee. (2020). Analyzing Investments in Flood Protection Structures: A Real Options Approach. International Journal Of Disaster Risk Reduction, 43.
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Abstract
The soaring number of natural hazards in recent years due largely to climate change has resulted in an even higher level of investment in flood protection structures. However, such investments tend to be made in the aftermath of disasters. Very little is known about the proactive planning of flood protection investments that account for uncertainties associated with flooding events. Understanding the uncertainties such as when to invest on these structures to achieve the most optimal cost-saving amount is outmost important. This study fills this large knowledge gap by developing an investment decision-making assessment framework that determines an optimal timing of flood protection investment options. It combines real options with a net present value analysis to examine managerial flexibility in various investment timing options. Historical data that contain information about river water discharges were leveraged as a random variable in the modeling framework because it may help investors better understand the probability of extreme events, and particularly, flooding uncertainties. A lattice model was then used to investigate potential alternatives of investment timing and to evaluate the benefits of delaying investments in each case. The efficacy of the proposed framework was demonstrated by an illustrative example of flood protection investment. The framework will be used to help better inform decision makers.
Keywords
Decision-making; Flood Protection; Real Options Theory; Investment Decision-making
Habibnezhad, Mahmoud; Puckett, Jay; Jebelli, Houtan; Karji, Ali; Fardhosseini, Mohammad Sadra; Asadi, Somayeh. (2020). Neurophysiological Testing for Assessing Construction Workers’ Task Performance at Virtual Height. Automation In Construction, 113.
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Abstract
Falling from heights is the primary cause of death and injuries at construction sites. As loss of balance has a fundamental effect on falling, it is important to understand postural regulation behavior during construction tasks at heights, especially those that require precise focus in an upright standing position (therefore, a dual-task demand on focus). Previous studies examined body sway during a quiet stance and dual tasks to understand latent factors affecting postural balance. Despite the success of these studies in discovering underlying factors, they lack a comprehensive analysis of a task's simultaneous cognitive load, postural sway, and visual depth. To address this limitation, this paper aims to examine construction workers' postural stability and task performance during the execution of visual construction tasks while standing upright on elevated platforms. To that end, two non-intrusive neurophysiological tests, a hand-steadiness task (HST) and a pursuit task (PT), were developed for construction tasks in a virtual environment (VE) as performance-based means to assess the cognitive function of workers at height. Workers' postural stability was measured by recording the mapped position of the Center of Pressure (COP) of the body on a posturography force plate, and the postural sway metrics subsequently calculated. A laboratory experiment was designed to collect postural and task performance data from 18 subjects performing the two batteries of tests in the virtual environment. The results demonstrated a significant decrease in the Root-Mean Square (RMS) of COP along the anterior-posterior axis during the Randomized Pursuit Task (RPT) and maximum body sway of the center of pressure (COP) in the mediolateral direction during both tests. Also, subjects exposed to high elevation predominately exhibit higher accuracy for RPT (P-value = 0.02) and lower accuracy for HST (P-value = 0.05). The results show that the combination of elevation-related visual depth and low-complexity dual tasks impairs task performance due to the elevation-induced visual perturbations and anxiety-driven motor responses. On the other hand, in the absence of visual depth at height, high task complexity surprisingly improves the pursuit tracking performance. As expected, during both tasks, alterations in postural control were manifested in the form of a body sway decrement as a compensatory postural strategy for accomplishing tasks at high elevation.
Keywords
Task Performance; Construction Workers; Test Design; Cognitive Load; Standing Position; Sitting Position; Neurophysiological Test; Postural Stability; Virtual Reality; Workers' Safety At Height; Fall-risk; Reaction-time; Fear; Real; Acrophobia; Balance; Safety
Soltaninejad, Mostafa; Fardhosseini, Mohammad Sadra; Kim, Yong Woo. (2021). Safety Climate and Productivity Improvement of Construction Workplaces Through the 6S System: Mixed-Method Analysis of 5S and Safety Integration. International Journal Of Occupational Safety & Ergonomics, 28(3), 1811-1821.
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Abstract
The purpose of this study is to develop a framework for integrating essential safety practices (visualization, job safety analysis and plan-do-check-act) into 5S steps and validate it. First, 18 interviews with a snowball sample of construction workers, safety representatives, supervisors and site and project managers were conducted. A grounded theory method was utilized to code the interview data. The results revealed that the studied construction companies implement a systematic safety-based methodology to minimize construction work injuries. Second, to validate the proposed framework, a pre-test and post-test study was applied. The case and control groups (26 participants) answered a 6S questionnaire before the 6S system and 1 month after implementation. The results revealed that safety climate and productivity significantly increased for the case group but reduced for the control group during time.
Keywords
5s Method; 6s System; Grounded Theory; Lean Construction; Productivity; Safety Climate; Health; Management; Leadership; Culture; Impact
The Energy and Sustainability in Construction (ESC) Lab promotes energy efficiency and sustainability (EES) in the built environment through the development of sustainable design, innovative project delivery practices, and risk-based financial models for EES investments. Our work focuses on integrating advanced financial analysis, project development, and management strategies to enhance the delivery of energy-efficient buildings and sustainable infrastructure.
Through innovative solutions, the ESC Lab addresses complex challenges in current project development practices that slow the transition toward a more sustainable society. Our research spans a wide range of critical areas, including commercial energy retrofits, community solar projects, green datacenters, healthy commercial buildings, and electric vehicle (EV) charging infrastructure. By tackling these pressing issues, the ESC Lab is at the forefront of driving transformative changes in the built environment.
Financial and Management Questions that Lead to Sustainable Solutions
The ESC Lab targets to help project stakeholders evaluate the risks and rewards of energy efficiency and sustainability (EES) investments by addressing some of the industry’s most pressing financial and management challenges, including:
- What policies, financing mechanisms, and project delivery systems best support the advancement of EES?
- How can we categorize and accurately model the unique risks associated with EES investments?
- What analytical modeling methods can be applied to ensure the effective implementation of EES measures in projects?
- How can we optimize investment strategies to balance environmental benefits with financial returns?
- What best practices can enhance stakeholder engagement and collaboration to drive successful EES project outcomes?
Pursuing Innovative Solutions to Energy Efficiency and Sustainability
The ESC Lab has developed a series of analytical models and evaluation practices that facilitate the effective delivery of energy-efficient commercial buildings and sustainable infrastructure, including:
- Cost and power demand model for electric vehicle (EV) charging infrastructure
- Conceptual cost and carbon estimating model for mass timber structure
- Energy-Related Risk Management in Integrated Project Delivery
- Phased Investment for Energy Retrofit (PIER)
- Energy Retrofit Loan Analysis Model (ERLAM)
- An optimized portfolio analysis for community-based photovoltaic investment
ESC Research Funders and Selected Projects:
- UW Clean Energy Institute: “Equitable Public Electric Vehicle Charging Infrastructure Expansion—From the Tribal Community Perspective”
- King County Metro–Sound Transit–Seattle City Light: “Electrified Mobility Hubs: A Blueprint for the Future of Transit Infrastructure”
- UW Global Innovation Fund: “Mitigating Effects of Future Pandemics with the Use of Risk-Responsive Building Codes: A Developing Country Framework”
- King County Metro: “Evaluation of a Public/Private Partnership (P3) Model for Bus Base Electrification”
- UW CBE INSPIRE Fund: “Investigating the Health Requirements and Risk-Responsiveness Criteria in Office Building Codes for Mitigating COVID-19 and Future Airborne Diseases”
- UW CBE INSPIRE Fund: “Investigating Energy Justice in Washington State in Terms of Photovoltaic (PV) Systems and Electric Vehicle (EV) Chargers”
- Google: “A Proposal to Grow a Greener Data Center with Google”
- UW Population Health: “Economic Impact of Office Workplace Transformation due to COVID-19: How Can Buildings and Surrounding Areas Recover?”
- UW Transportation: “UW Transportation Electrification and Solar Study”
- RERI–LBNL–DOE: “Effect of Energy Benchmarking and Disclosure on Office Building Marketability”
- Pankow–Skanska–Oregon DEQ: “Life Cycle Assessment (LCA) for Low Carbon Construction Commercial Office Building MEP & Interiors Data”
- BE Innovation: “Impact of Energy Benchmarking and Disclosure on the Performance of Office Buildings”
Selected Journal Publications:
- Min, Y. and Lee, H.W. (2024). “Adoption Inequalities and Causal Relationship between Residential Electric Vehicle Chargers and Heat Pumps.” ASCE Journal of Construction Engineering and Management, 04024025.
- Min, Y. and Lee, H.W. (2024). “Quantifying Clean Energy Justice: Impact of Solarize Programs on Rooftop Solar Disparities in the Pacific Northwest.” Sustainable Cities and Society, 105287.
- Shang, L., Dermisi, S., Choe, Y., Lee, H.W., and Min, Y. (2023). “Assessing the Office Building Marketability Before and After the Implementation of Energy Benchmarking and Disclosure Policies – Lessons Learned from Major US Cities.” Sustainability, 15(11), 8883.
- Min, Y. and Lee, H.W. (2023). “Characterization of Vulnerable Communities in Terms of the Benefits and Burdens of the Energy Transition in Pacific Northwest Cities.” Journal of Cleaner Production, 135949.
- Min, Y., Lee, H.W., and Hurvitz, P.M. (2023). “Clean Energy Justice: Different Adoption Characteristics of Underserved Communities in Rooftop Solar and Electric Vehicle Chargers in Seattle.” Energy Research and Social Science, 96(1), 102931.
- Su, S., Li, X., Zhu, C., Lu, Y., and Lee, H.W. (2021). “Dynamic Life Cycle Assessment: A Review of Research for Temporal Variations in Life Cycle Assessment Studies.” Environmental Engineering Science, 38(11).
- Droguett, B. X. R., Huang, M., Lee, H.W., Simonen, K., and Ditto, J. (2020). “Mechanical, Electrical, Plumbing and Tenant Improvements Over the Building Lifetime: Estimating Material Quantities and Embodied Carbon for Climate Change Mitigation.” Energy and Buildings, 226, 110324.
- Ho, C., Lee, H.W., and Gambatese, J. (2020). “Application of Prevention through Design (PtD) to Improve the Safety of Solar Installations on Small Buildings.” Safety Science, 125, 104633.
- Gomez Cunya, L.A., Fardhosseini, M.S., Lee, H.W., and Choi, K. (2020). “Analyzing Investments in Flood Protection Structures: A Real Options Approach.” International Journal of Disaster Risk Reduction, 43(2), 101377.
- Shang, L., Lee H.W., Dermisi, S., and Choe, Y., (2020). “Impact of Energy Benchmarking and Disclosure Policy on Office Buildings.” Journal of Cleaner Production, 250, 119500.
- Shakouri, M., Lee, H.W., and Kim, Y.-W. (2017). “A Probabilistic Portfolio-based Model for Financial Valuation of Community Solar.” Applied Energy, 191(1), 709-726.
- Shakouri, M. and Lee, H.W. (2016). “Mean-Variance Portfolio Analysis Data for Optimizing Community-based Photovoltaic Investment.” Data in Brief, 6(1), 840-842.\
Current and Former Lab Members:
- Abdul-Razak Alidu
- Byungju Jeon
- Chitika Vasudeva
- Yohan Min
- Matt Wiggins
- Novi T.I. Bramono
- Yong-Hyuk Oh
- Chuou Zhang
- Jonghyeob Kim
- Wenqi Zhu
- Julie Knorr
- Zhila Mohammady