Min, Yohan; Lee, Hyun Woo. (2023). Characterization of Vulnerable Communities in Terms of the Benefits and Burdens of the Energy Transition in Pacific Northwest Cities. Journal of Cleaner Production.
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Abstract
Energy transition to renewable sources has occurred along with the development of various clean energy policies aimed at decarbonization and electrification. However, the transition can inadvertently lead to social inequity resulting in increasing burdens on vulnerable communities. Although many studies have tried to define and identify vulnerable communities, there has been no study specifically aimed at characterizing vulnerable communities in terms of the benefits and burdens of such energy transition. In response, the objective of this study is to characterize vulnerable communities by examining rooftop solar adoption and energy expenditure using spatial and mixed-effect models. Rooftop solar adoption operationalizes energy resilience and benefits, and energy expenditure operationalizes energy dependence and burdens of the transition. The study also investigates the link between rooftop solar adoption and energy expenditure by considering city-level variability in three Pacific Northwest cities. The results show that Bellevue has 50.4% less rooftop solar adoption than Portland, while Portland has 16.1% or $223 more energy expenditure than Seattle. On average, an increase in annual energy expenditure of $431 is associated with 29% increase in rooftop solar adoption, specifically Bellevue, Seattle, and Portland by 21.4%, 39.1%, and 26.2%, respectively, but not vice versa. Furthermore, the group of communities more vulnerable in housing attributes has 15.2% less rooftop solar adoption than the group of more vulnerable communities in socioeconomic attributes. In addition, the city centers, commercial areas, or mid-rise and high-rise zones are found to have lower rooftop solar adoption and energy expenditure than other areas. The results suggest that policymakers should consider between-city variability when identifying vulnerable communities. Policies should also be tailored to local communities based on their attributes as communities with similar attributes tend to cluster together. Furthermore, policymakers should focus more on housing and built environment attributes to promote resilient communities.
Ottesen, Jeffrey L., & Migliaccio, Giovanni (2023). Use of Predictive Models for Labor-Productivity Loss in Settling Disputes. Journal of Legal Affairs and Dispute Resolution in Engineering and Construction, 15(1).
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Abstract
Given inherent difficulties in construction, optimizing labor efficiencies is paramount to project success. Research described in this article conducted demonstrates that an analysis of planned activities in a critical path methodology (CPM) schedule may be used to forecast future productivity inefficiencies. Specifically, this study relies on the concept of CPM schedule’s density, which is defined as the number of overlapping like-trade activities on any given workday. This metric is directly related to the required labor resources required to complete that work within the activities’ planned durations. Schedule density increases where more planned activities overlap with each other; for instance, occurrence of such increases is common when the schedule is accelerated. Regression models were derived using metrics drawn from CPM schedule updates’ activities and durations and compared to actual labor productivity experienced. Strong correlation findings support development of predictive models that quantify potential labor inefficiencies before they occur. However, the question remains as to the strength and applicability of predictive models in formal litigation. This paper presents findings of this research and discusses how such findings may be used to facilitate settlement in dispute resolution procedures.
Keywords
Migliaccio, Giovanni C., Gebken, Richard J., Fernandez, Luis R., & Osmanbhoy, Natasha (2022). Emergent Subcontracting Models in the US Construction Industry. Journal of Legal Affairs and Dispute Resolution in Engineering and Construction, 14(4).
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Abstract
Prime contracting models for engineering and construction projects are described extensively in the literature, but models between prime contractors and subcontractors are less well known. This study examined the established and evolving subcontracting models in the US construction industry to not only document their utilization but also investigate their advantages and disadvantages when employed. The research followed a two-phase/two-step approach. During Phase 1, the authors completed a regionally based study to identify subcontracting practices in the Pacific Northwest. As part of Phase 2, the study was expanded across the United States to gain a greater understanding of each of the identified subcontracting models, including advantages, disadvantages, and variations. Both phases were organized into two steps: (1) an online survey instrument was sent to professionals with either general or specialty contracting firms, and (2) follow-up semistructured interviews were conducted with selected survey respondents to better evaluate each subcontracting model. The authors found that five subcontracting models address the most common scenarios and the characteristics of each are familiar to the nationwide participant sample. There are subtle variations to the main five models that are being employed to varying degrees across the country. The impetus for these variations appears to be founded on the need to find better contractual arrangements and that subcontracting practices are dynamic by nature. Although most of the participants were from western and central divisions of the US Census Bureau geographical classification, participants from all geographic areas participated in the study. Increasing knowledge on how project delivery systems may affect disputes and claims or conflicts and legal issues of procurement systems, this article uniquely contributes to defining a taxonomy of subcontracting models while giving insights into the current and emerging trends in subcontracting practices, including how subcontractors are integrated into a project team.
Migliaccio, Giovanni C., & Shrestha, Pramen P. (Eds.). (2023). Building a Body of Knowledge in Construction Project Delivery, Procurement and Contracting. World Scientific.
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Abstract
This book aims to consolidate, structure and articulate collective knowledge on construction project delivery, procurement and contracting, so that it can serve as a gateway to the contiguous topics of construction project delivery. In addition to supporting the education of student researchers, as well as broadening and deepening the knowledge of practitioners, the book is also intended to serve as a foundation for future education and as a reference book. Academicians can use it to benchmark and support their research and also as a textbook for an undergraduate or graduate course on the topics of project delivery, procurement and contracting.
Keywords
Construction; Engineering; Project Delivery; Procurement; Contracting
The American Institute of Architects (AIA) recently published a supplement to the AIA Guides for Equitable Practice titled “Equity in Architectural Education.” Renée Cheng, dean of the College of Built Environments, served as the project lead for the research and writing team, which included Laura Osburn, research scientist in construction management. The supplement argues that organizational culture is critical to achieving goals of equity, diversity, and inclusion, and is intended to inspire discussion within individual institutions, and among thought leaders…
Emami, Anahita; Sah, Hos Narayan; Aguayo, Federico; Khaleghian, Seyedmeysam. (2022). Experimental Investigations and Empirical Modeling of Rubber Wear on Concrete Pavement. Journal of Engineering Tribology.
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Abstract
Material loss due to wear plays a key role in the service life of rubber components in various tribological applications, such as tires, shoe soles, wiper blades, to name a few. It also adversely affects energy consumption, economy, and CO2 emissions around the globe. Therefore, understanding and modeling the wear behavior of rubbers are important in the design of economic and environment-friendly rubber compounds. In this study, we investigated the effect of normal load and sliding velocity on the wear rate of rubber compounds widely used in the tire treads and evaluated the wear models previously proposed for rubbers to determine the best model to predict the rubber wear rate. The sliding wear rates of different types of Styrene-Butadiene Rubber (SBR) and Isoprene Rubber (IR) compounds on a broom finish concrete slab were measured for different sliding velocities and normal loads. The experimental results were used to evaluate and discuss different wear models proposed in the literature. A new empirical model was proposed to predict the wear rate by considering mechanical properties associated with rubber wear. The experimental results revealed that the wear rate of rubber compounds non-linearly depends on the normal load or friction force, while the effect of sliding velocity on the wear rate is not significant in the 20–100 mm/s range. Moreover, traces of both mechanical (abrasion) and chemical (smearing) wear were observed on all rubber compounds.
Keywords
Tire tread compounds, rubber wear, rubber-concrete interaction, smearing wear and abrasion, wear model
Okechi, Ikechukwu K.; Aguayo, Federico; Torres, Anthony. (2022). Coefficient of Thermal Expansion of Concrete Produced with Recycled Concrete Aggregates. Journal of Civil Engineering and Construction, 11(2), 65-74.
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Abstract
This study presents a comparison between the coefficient of thermal expansion (CTE) of concrete produced with natural aggregate and that of concrete produced with recycled concrete aggregate. In order to achieve this, natural aggregate concrete (NAC) specimens were produced, tested, then crushed and sieved in the laboratory to obtain recycled concrete aggregates, which was then used in the production of recycled aggregate concrete (RAC) specimens. The RAC samples were then tested and compared to the NAC samples. The CTE testing was carried out using a AFTC2 CTE measurement system produced by Pine Instrument Company. In addition to CTE testing, the water absorption, specific gravity, and unit weight of the aggregates was determined. A vacuum impregnation procedure was used for the water absorption test. The recycled aggregate properties showed a significantly higher absorption capacity than that of the natural aggregates, while the unit weight and specific gravity of the recycled aggregate were lower than that of the natural aggregates. The average CTE results showed that both the NAC and the RAC samples expanded similarly. The results show that the CTE of RAC depends on the natural aggregate used in the NAC, which was recycled to produce the RAC. Also, there was no significant difference between the average CTE values of the RAC and that of NAC that could discredit the use of recycled aggregate in concrete.
Keywords
Coefficient of thermal expansion; Recycled concrete aggregate; Natural concrete aggregate.
Kim, Minju; Lee, Dongmin; Kim, Taehoon; Oh, Sangmin; Cho, Hunhee. (2023). Automated Extraction of Geometric Primitives with Solid Lines from Unstructured Point Clouds for Creating Digital Buildings Models. Automation In Construction, 145.
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Abstract
Point clouds produced by laser scanners are an invaluable source of data for reconstructing multi-dimensional digital models that reflect the as-is conditions of built facilities. However, previous studies aimed to reconstruct models by overlaying the dataset on top of ground-truth reference models to manually adjust the accuracy of the output. Therefore, this paper describes the extraction of geometric primitives with solid lines—the simplest form of objectified data that computer-aided design systems can handle—from unorganized data points and creation of digital models of built facilities in a form of floor plan. The geometric primitives are extracted from 3D points by hybridizing machine learning algorithms, which are mean-shift clustering, non-convex hull, and random sample and consensus (RANSAC). This paper provides a solution for creating a new form of as-built model with high accuracy and robustness from scratch without the involvement of ground-truth solutions or manual adjustments. © 2022 Elsevier B.V.
Keywords
Computer Aided Design; Geometry; Laser Applications; Learning Algorithms; Machine Learning; Scanning; As-build Model Creation; Build Facility; From-point-to-line; Geometric Primitives; Laserscanners; Model Creation; Outline Extractions; Point-clouds; Point-to-line; Solid Lines
Osburn, Laura; Lee, Hyun Woo; Gambatese, John A. (2022). Formal Prevention through Design Process and Implementation for Mechanical, Electrical, and Plumbing Worker Safety. Journal Of Management In Engineering, 38(5).
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Abstract
There are many studies that focus on Prevention through Design (PtD) for construction workers and developing formalized PtD processes for construction projects. However, few studies have aimed at developing a formalized PtD process for mechanical/electrical/plumbing (MEP) worker safety. A formal process for implementing PtD for MEP worker safety is badly needed because MEP work onsite and during operation and maintenance (O&M) can lead to injury and death. To address this knowledge gap, our research team aimed to create a formalized PtD process for MEP safety and developed case studies that detail how the process can be implemented in the field. The formalized process and case studies would then be used in an implementation guide created specifically for the industry. This project was completed through expert interviews, six case studies, and ongoing discussion and review by an Industry Advisory Council. Using these methods, the team identified factors for implementation success and developed a formalized PtD process specific to the MEP worker context. The process consists of five phases: (1) hazard identification, (2) risk assessment, (3) design review, (4) implementation, and (5) learning. We anticipate that this study will contribute to the field of PtD research through creating one of the first formalized PtD processes for MEP construction and O&M worker safety, and through a cross-case analysis of the six PtD cases that indicated not only the importance of stakeholder engagement and cross-disciplinary dialogue, but that effective PtD implementation can occur even outside of a collaborative project delivery context at any point during design and construction.
Keywords
Construction Safety; Health; Attitude; Prevention Through Design (ptd); Construction Worker Safety; Mechanical; Electrical; Plumbing (mep)
Asl, Bita Astaneh; Dossick, Carrie Sturts. (2022). Immersive VR Versus BIM for AEC Team Collaboration in Remote 3D Coordination Processes. Buildings, 12(10).
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Abstract
Building Information Modeling (BIM) and Virtual Reality (VR) are both tools for collaboration and communication, yet questions still exist as to how and in what ways these tools support technical communication and team decision-making. This paper presents the results of an experimental research study that examined multidisciplinary Architecture, Engineering, and Construction (AEC) team collaboration efficiency in remote asynchronous and synchronous communication methods for 3D coordination processes by comparing BIM and immersive VR both with markup tools. Team collaboration efficiency was measured by Shared Understanding, a psychological method based on Mental Models. The findings revealed that the immersive experience in VR and its markup tool capabilities, which enabled users to draw in a 360-degree environment, supported team communication more than the BIM markup tool features, which allowed only one user to draw on a shared 2D screenshot of the model. However, efficient team collaboration in VR required the members to properly guide each other in the 360-degree environment; otherwise, some members were not able to follow the conversations.
Keywords
Mental Models; Virtual-reality; Performance; Virtual Reality (vr); Building Information Modeling (bim); 3d Coordination; Clash Resolution; Remote Collaboration; Multidisciplinary Aec Team