Choi, Kunhee; Lee, Hyun Woo; Bae, Junseo; Bilbo, David. (2016). Time-Cost Performance Effect of Change Orders from Accelerated Contract Provisions. Journal Of Construction Engineering And Management, 142(3).
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Abstract
Accelerated contract provisions (ACPs) such as cost-plus-time (A+B) and incentives/disincentives (I/D) are increasingly common, yet very little is known about their pure time-cost performance effects on change orders. To fill this large knowledge gap, a two-stage research methodology drawing on 1,372 highway improvement projects completed in California was adopted for this study. The Stage I study investigated the marginal change-order impacts of two ACPs, pure A+B and I/D combined with A+B. How ACP change orders affect projects' time-cost performance was numerically modeled and successfully validated over the Stage II study. The results clearly showed that both ACPs led to more schedule-change and cost-change orders than conventionally contracted projects, whereas I/D combined with A+B performed significantly better than pure A+B in terms of the magnitude of schedule-change orders. This conveys an important recommendation to state transportation agencies (STAs) that A+B be used with an I/D provision. The results and numerical models of this study would help STAs better assess and justify the impact of change orders on the duration and cost of projects, enabling them to more effectively use contingency amounts. Use of the models can also benefit contractors requesting a change order because the models can provide them with advanced knowledge of the probable time-cost growth rates specifically for the pursued ACP. (C) 2015 American Society of Civil Engineers.
Keywords
Construction Industry; Contracts; Costing; Incentive Schemes; Numerical Analysis; Order Processing; Performance Evaluation; Roads; Scheduling; Time Management; Transportation; Projects Time-cost Performance Effect; Cost-change Order; Accelerated Contract Provision; Knowledge Gap; California; Acp; Schedule-change Order; State Transportation Agency; Numerical Model; Sta; Incentive; Highway Improvement Project; Labor Productivity; Construction; Impact; Model; Projects; Change Order; Highway Rehabilitation; Decision Modeling; Regression; Validation; Contracting
Way, Thaisa. (2016). The Urban University’s Hybrid Campus. Journal Of Landscape Architecture, 11(1), 42 – 55.
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Abstract
With the growth of urban campuses in the twenty-first century, how can landscape architecture foster the innovation associated with cities and urban neighbourhoods? In Seattle, West Campus at the University of Washington serves as a good urban neighbour while engaging the traditional experiences of a campus. Additionally, the design suggests how an urban campus might generate the culture of an urban innovation district. The contribution of landscapes to innovation districts has rarely been considered in campus design because the focus has been on the architecture of the buildings and the culture of collaboration as social phenomena. This paper explores how the public landscapes of parks, courtyards, and streets shape the experience of an innovation district and contribute to fostering creativity and serendipity. As an extension, the paper suggests the importance of universities in the creation and stewardship of vibrant, creative, and resilient cities.
Keywords
City Planning; Innovation District; Student Residential Planning; University Landscape Design; Urban Campus
Bender, W.; Waytuck, D.; Wang, S.; Reed, D. A. (2018). In Situ Measurement of Wind Pressure Loadings on Pedestal Style Rooftop Photovoltaic Panels. Engineering Structures, 163, 281 – 293.
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Abstract
The installation of rooftop photovoltaic (PV) arrays is increasing throughout the US. Until recently, pedestal type PV framing systems for rooftops were basically designed using procedures from the ASCE7-10 Components and Cladding Standard for rooftop equipment. The 2011 Japanese Standard Load design guide on structures for photovoltaic arrays was useful in characterizing the pressure coefficients on rooftops, but the Standard employs different wind speed and importance factors, making its use in the US quite limited, Even the updated 2017 version is written for a different audience. Because rooftop pressure loadings are high due to flow separation, SEAOC and other organizations contracted boundary layer wind tunnel tests of panels attached to rooftops to ascertain if the ASCE7-10 equipment loadings were appropriate. The investigations resulted in new standards for pedestal-style arrays that appear in Chapter 29 of ASCE7-16. However, the new standards are limited to simple geometries and orientations, and the dynamics of the simply-supported thin PV plates do not appear to be considered. Questions regarding the ability of the boundary tunnels to simulate accurately the turbulence at the scale required for the attached panels have been raised. In response, very limited full-scale investigations in large-scale tunnels and in situ have been undertaken to calibrate the tunnel results. The results of this paper represent one of these calibration investigations. Specifically, in situ full-scale net wind pressure loadings on a rooftop PV array in a pedestal-style framing system located on the three story Hogue Technology Building of Central Washington University (CWU) in Ellensburg, Washington were measured. The CWU campus has a rural setting in a region with steady winds: Ellensburg is located in the Kittitas Breezeway portion of the Northwest wind power region. Indeed, the Wild Horse Wind and Solar Farm is located on the outskirts of town. The data described here were collected from April through August 2014. The measured net pressure coefficient time series were similar to those for rooftop pressure loadings for low-rise buildings described in the literature such as the Wind Engineering Research Field Laboratory at Texas Tech University (Ham and Bienkiewicz, 1998 [1]; Levitan and Mehta, 1992 [2]). The analysis of the net pressure time series data included an examination of the minimum, maximum, mean, and RMS values. Preliminary results suggest that the range of the values is larger than assumed in the ASCE7 Standard, and that the magnitude of the loadings vary considerably spatially over the multiple panel array. The pressure loading measurements are ongoing.
Keywords
Building Integrated Photovoltaics; Buildings (structures); Calibration; Design Engineering; Pressure Measurement; Roofs; Solar Cell Arrays; Standards; Time Series; Turbulence; Wind Tunnels; Japanese Standard Load Design Guide; Wind Pressure Loading Measurements; Asce7-10 Components-cladding Standard; Tunnel Calibration; Texas Tech University; Kittitas Breezeway Portion; Wild Horse Wind And Solar Farm; Ellensburg; Central Washington University; Hogue Technology Building; Boundary Layer Wind Tunnel Test; Flow Separation; Multiple Panel Array; Wind Engineering Research Field Laboratory; Net Pressure Coefficient Time Series; Northwest Wind Power Region; Pedestal-style Framing System; Pv Plates; Rooftop Equipment; Pedestal Style Rooftop Photovoltaic Panels; Solar-arrays; Loads; Simulation; Wind Engineering; Photovoltaic Modules; Solar Energy; Full-scale Measurements; Wind Loadings; Photovoltaic Cells; Roofing; Wind Power; Structural Engineering; Boundary Layers; Cladding; Wind Tunnel Testing; Solar Cells; In Situ Measurement; Framing; Photovoltaics; Engineering Research; Wind Measurement; Pressure; Panels; Wind Pressure; Design Standards; Fluid Dynamics; Low Rise Buildings; Colleges & Universities; Wind Speed; United States--us
Abdirad, Hamid; Dossick, Carrie S. (2019). Normative and Descriptive Models for COBie Implementation: Discrepancies and Limitations. Engineering, Construction And Architectural Management, 26(8), 1820 – 1836.
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Abstract
Purpose The purpose of this paper is to inquire into the reasons why Construction Operation Building Information Exchange (COBie) has not become mainstream across the construction industry despite the significant attempts to promote it. Design/methodology/approach This paper framed and compared the normative model of COBie to a descriptive model of COBie. The normative model was based on the assumptions and planned procedures outlined in the COBie documentation. The descriptive model was developed through a case study of COBie implementation, with ethnographic observations, interviews and artifact analysis as the data collection methods and thematic analysis as the data analysis method. Findings The comparative analysis of the normative and descriptive models showed that the underlying normative assumptions of COBie can be challenged in its implementation. In the case study, implementing COBie disrupted the conventional practice of few participating firms as the data requirements and the expected sequences and timelines of tasks were not aligned with the industry norms for exchanging data. Furthermore, the normative model of COBie could not account for the unanticipated variability in the internal routines of firms for submittal production. Practical implications - COBie, as an instruction-based model, may not provide enough flexibility for some firms to adapt to its requirements such that COBie tasks become integrated with their existing workflows. COBie tasks may become additional efforts, and at times, conflict with the industry norms and firms' routines, and therefore, disrupt the efficiency goals. Originality/value This paper provides empirical evidence to clarify why implementing COBie has not been as efficient for all industry players as expected.
Keywords
Construction Industry; Information Dissemination; Information Systems; Cobie; Hand Over; Information And Communication Technologies; Information Exchanges; Operations; Facilities Management; Bim; Construction; Case Study; Information Exchange; Information And Communication Technology (ict) Applications; Project Hand Over
Prakash, Vikramaditya. (2019). Dhāranā: The Agency of Architecture in Decolonization. Future Anterior, 16(2), 87 – 120.
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Lee, Wonil; Migliaccio, Giovanni C.; Lin, Ken-Yu; Seto, Edmund Y. W. (2020). Workforce Development: Understanding Task-Level Job Demands-Resources, Burnout, and Performance in Unskilled Construction Workers. Safety Science, 123.
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Abstract
This study examines how task demands and personal resources affect unskilled construction worker productivity and safety performance. It extends the job demands-resources (JD-R) burnout model to show how job characteristics interact with burnout to influence performance. A modified model was designed to measure burnout, with exhaustion and disengagement among unskilled construction workers taken into consideration. An observational study was conducted in a laboratory environment to test the research hypotheses and assess the prediction accuracies of outcome constructs. Twenty-two subjects participated in multiple experiments designed to expose them to varying levels of task-demands and to record their personal resources as they performed common construction material-handling tasks. Specifically, both surveys and physiological measurements using wearable sensors were used to operationalize the model constructs. Moreover, partial least squares structural equation modeling was applied to analyze data collected at the task and individual levels. Exhaustion and disengagement exhibited different relationships with productivity and safety performance outcomes as measured by unit rate productivity and ergonomic behavior, respectively. Subjects with high burnout and high engagement showed high productivity but low safety performance. Thus, exhausted workers stand a greater chance of failing to comply with safety. As the sample and the task performed in the experiment do not cover the experience and trade of all construction workers, our findings are limited in their application to entry-level and unskilled workers, whose work is mainly manual material-handling tasks.
Keywords
Construction Workers; Structural Equation Modeling; Job Descriptions; Labor Productivity; Labor Supply; Burnout; Job Demand-resources Model; Partial Least Squares Structural Equation Modeling; Productivity; Safety; Wearable Sensors; Biomechanics; Construction Industry; Ergonomics; Occupational Health; Occupational Safety; Occupational Stress; Personnel; Statistical Analysis; Workforce Development; Understanding Task-level Job Demands-resources; Unskilled Construction Workers; Task Demands; Personal Resources; Unskilled Construction Worker Productivity; Job Demands-resources Burnout Model; Job Characteristics Interact; Exhaustion; Disengagement; Outcome Constructs; Varying Levels; Task-demands; Common Construction Material-handling Tasks; Physiological Measurements; Model Constructs; Individual Levels; Unit Rate Productivity; High Burnout; Low Safety Performance; Exhausted Workers; Entry-level; Unskilled Workers; Manual Material-handling Tasks; Heart-rate-variability; Labor Productivity Trends; Physiological Demands; Emotional Exhaustion; Safety Climate; Role Stress; Engagement; Fatigue; Workload; Task Analysis; Workforce; Level (quantity); Construction Materials; Personnel Management; Materials Handling; Multivariate Statistical Analysis
Choi, Kunhee; Bae, Junseo; Yin, Yangtian; Lee, Hyun Woo. (2021). Act(2): Time Cost Tradeoffs from Alternative Contracting Methods. Journal Of Management In Engineering, 37(1).
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Abstract
Incentive/disincentive (I/D) and cost-plus-time (A+B) are two of the most widely used alternative contracting methods (ACMs) for accelerating the construction of highway infrastructure improvement projects. However, little is known about the effects of trade-offs in terms of project schedule and cost performance. This study addresses this problem by creating and testing a stochastic decision support model called accelerated alternative contracting cost-time trade-off (ACT(2)). This model was developed by a second-order polynomial regression analysis and validated by the predicted error sum of square statistic and paired comparison tests. The results of a descriptive trend analysis based on a rich set of high-confidence project data show that I/D is effective at reducing project duration but results in higher cost compared to pure A+B and conventional methods. This cost-time trade-off effect was confirmed by the ACT(2) model, which determines the level of cost-time trade-off for different ACMs. This study will help state transportation agencies promote more effective application of ACMs by providing data-driven performance benchmarking results when evaluating competing acceleration strategies and techniques. (C) 2020 American Society of Civil Engineers.
Keywords
Highway; Construction; Model; Alternative Contracting Methods; Cost-plus-time; A Plus B; Incentive; Infrastructure Trend; Time-cost Trade-off
Zuidema, Christopher; Austin, Elena; Cohen, Martin A.; Kasner, Edward; Liu, Lilian; Isaksen, Tania Busch; Lin, Ken-Yu; Spector, June; Seto, Edmund. (2022). Potential Impacts Of Washington State’s Wildfire Worker Protection Rule On Construction Workers. Annals Of Work Exposures & Health, 66(4), 419 – 432.
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Abstract
Driven by climate change, wildfires are increasing in frequency, duration, and intensity across the Western United States. Outdoor workers are being exposed to increasing wildfire-related particulate matter and smoke. Recognizing this emerging risk, Washington adopted an emergency rule and is presently engaged in creating a permanent rule to protect outdoor workers from wildfire smoke exposure. While there are growing bodies of literature on the exposure to and health effects of wildfire smoke in the general public and wildland firefighters, there is a gap in knowledge about wildfire smoke exposure among outdoor workers generally and construction workers specifically-a large category of outdoor workers in Washington totaling 200,000 people. Several data sources were linked in this study-including state-collected employment data and national ambient air quality data-to gain insight into the risk of PM2.5 exposure among construction workers and evaluate the impacts of different air quality thresholds that would have triggered a new Washington emergency wildfire smoke rule aimed at protecting workers from high PM2.5 exposure. Results indicate the number of poor air quality days has increased in August and September in recent years. Over the last decade, these months with the greatest potential for particulate matter exposure coincided with an annual peak in construction employment that was typically 9.4-42.7% larger across Washington counties (one county was 75.8%). Lastly, the 'encouraged' threshold of the Washington emergency rule (20.5 mu g m(-3)) would have resulted in 5.5 times more days subject to the wildfire rule on average across all Washington counties compared to its 'required' threshold (55.5 mu g m(-3)), and in 2020, the rule could have created demand for 1.35 million N-95 filtering facepiece respirators among construction workers. These results have important implications for both employers and policy makers as rules are developed. The potential policy implications of wildfire smoke exposure, exposure control strategies, and data gaps that would improve understanding of construction worker exposure to wildfire smoke are also discussed.
Keywords
Particulate Matter; Industrial Safety; Occupational Exposure; Rules; Smoke; Construction Industry; Employment; Occupational Hazards; Descriptive Statistics; Industrial Hygiene; Wildfires; N95 Respirators; Washington (state); Forest Fires; Pm 2.5; Respirator; Wildfire Smoke Protection Rule; Wildland Fire; Pm2 5; Health Impacts; Climate-change; Forest-fire; Exposure; Firefighters; Infiltration
Dossick, Carrie S.; Neff, Gina. (2010). Organizational Divisions in BIM-Enabled Commercial Construction. Journal Of Construction Engineering And Management-asce, 136(4), 459 – 467.
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Abstract
Proponents claim that the adoption of building information modeling (BIM) will lead to greater efficiencies through increased collaboration. In this paper, we present research that examines the use of BIM technologies for mechanical, electrical, plumbing, and fire life safety systems (often referred to as MEP) coordination and how the introduction of BIM influences collaboration and communication. Using data from over 12 months of ethnographic observations of the MEP coordination process for two commercial construction projects and interviews with 65 industry leaders across the United States, we find that BIM-enabled projects are often tightly coupled technologically, but divided organizationally. This means that while BIM makes visible the connections among project members, it is not fostering closer collaboration across different companies. We outline the competing obligations to scope, project, and company as one cause for this division. Obligations to an individual scope of work or to a particular company can conflict with project goals. Individual leadership, especially that of the MEP coordinator in the teams we studied, often substitutes for stronger project cohesion and organization. Organizational forces and structures must be accounted for in order for BIM to be implemented successfully.
Keywords
Technology; Implementation; Viewpoint; Integrated Systems; Construction Industry; Leadership; Information Systems; Information Technology; Communication; Constructability; Mechanical Systems; Electrical Systems
Streatfield, David C. (2012). The San Francisco Peninsula’s Great Estates: Part I. Eden, 15(1), 1 – 14.
Abstract
The article presents a historical background of several great estates in San Francisco Peninsula in California known for their unique landscaping and special garden designs in the late 19th and early 20th centuries. It discusses the climate and settlement styles in the area and offers information on the earliest estates such as the El Cerrito created by merchant William Davis Merry Howard and the notable mid-Victorian estates such as the Millbrae estate of banker Darius Ogden Mills.
Keywords
Garden Design; Landscape Design; Landscape Gardening; San Francisco Peninsula (calif.); California