Kim, Tae-hyung; Lee, Hyun Woo; Hong, Seok-woo. (2016). Value Engineering for Roadway Expansion Project over Deep Thick Soft Soils. Journal Of Construction Engineering And Management, 142(2).
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Abstract
A roadway expansion that takes place on soft ground is susceptible to differential settlement because of the high consolidation of soft soils. Therefore, steps must be taken to lessen the risk of such settlement; yet, this often only results in costly drainage solutions. In that, applying a systematic value engineering (VE) process can be beneficial to develop cost-effective design alternatives. However, VE studies specifically targeting for this problem are absent from the field. Thus, the goal of this study is to supplement this knowledge gap by applying a systematic VE process to an expansion project on soft ground to demonstrate the benefits of performing VE. A case study was performed on an expansion project over a soft soil layer approximately 50m thick. Through the VE process, the original design was reviewed, problems were discussed, and three alternatives were proposed. Then value analysis techniques were applied to evaluate these alternatives in terms of cost saving, function improvement, and value improvement with respect to the original design. The VE process and design alternatives as applied in this study are expected to serve as a guideline for engineers and decision-makers in roadway expansion projects on soft ground. (C) 2015 American Society of Civil Engineers.
Keywords
Construction Industry; Costing; Project Management; Road Building; Soil; Value Engineering; Engineers; Decision-makers; Value Improvement; Function Improvement; Knowledge Gap; Cost-effective Design; Deep Thick Soft Soils; Soft Ground; Roadway Expansion Project; Systematic Value Engineering Process; Value Engineering (ve); Job Plan; Roadway Expansion; Deep Soft Ground; Differential Settlement; Cost Saving; Project Planning And Design
Schmiedeskamp, Peter; Zhao, Weiran. (2016). Estimating Daily Bicycle Counts in Seattle, Washington, from Seasonal and Weather Factors. Transportation Research Record, 2593, 94 – 102.
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Abstract
This paper examines the relationship between several seasonal and weather factors and bicycle ridership from 2 years of automated bicycle counts at a location in Seattle, Washington. The authors fitted a negative binomial model and then estimated quantities of interest using counterfactual simulation. The findings confirm the significance of season (+), temperature (+), precipitation (), as well as holidays (-), day of the week (+ for Monday through Saturday, relative to Sunday), and an overall trend (+). This paper improves on prior work by demonstrating the use of the negative binomial instead of a Poisson model, which is appropriate given the potential for overdispersion, as observed in these data. In addition to validating the significance of factors identified from the literature, this paper contributes methodologically through its intuitive visualization of effect sizes to nonstatistical audiences. The authors believe that the combination of model type and counterfactual simulation and visualization reflects a reasonable compromise between model complexity and interpretability. Results such as these can aid policy makers and planners in understanding bicycle travel demand elasticities and in guiding interventions aimed at increasing rates of bicycling. The methods presented are fully reproducible and invite adaptation to other locations.
Chaix, Basile; Duncan, Dustin; Vallee, Julie; Vernez-moudon, Anne; Benmarhnia, Tarik; Kestens, Yan. (2017). The Residential Effect Fallacy in Neighborhood and Health Studies Formal Definition, Empirical Identification, and Correction. Epidemiology, 28(6), 789 – 797.
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Abstract
Background: Because of confounding from the urban/rural and socioeconomic organizations of territories and resulting correlation between residential and nonresidential exposures, classically estimated residential neighborhood-outcome associations capture nonresidential environment effects, overestimating residential intervention effects. Our study diagnosed and corrected this residential effect fallacy bias applicable to a large fraction of neighborhood and health studies. Methods: Our empirical application investigated the effect that hypothetical interventions raising the residential number of services would have on the probability that a trip is walked. Using global positioning systems tracking and mobility surveys over 7 days (227 participants and 7440 trips), we employed a multilevel linear probability model to estimate the trip-level association between residential number of services and walking to derive a naive intervention effect estimate and a corrected model accounting for numbers of services at the residence, trip origin, and trip destination to determine a corrected intervention effect estimate (true effect conditional on assumptions). Results: There was a strong correlation in service densities between the residential neighborhood and nonresidential places. From the naive model, hypothetical interventions raising the residential number of services to 200, 500, and 1000 were associated with an increase by 0.020, 0.055, and 0.109 of the probability of walking in the intervention groups. Corrected estimates were of 0.007, 0.019, and 0.039. Thus, naive estimates were overestimated by multiplicative factors of 3.0, 2.9, and 2.8. Conclusions: Commonly estimated residential intervention-outcome associations substantially overestimate true effects. Our somewhat paradoxical conclusion is that to estimate residential effects, investigators critically need information on nonresidential places visited.
Keywords
Self-rated Health; Record Cohort; Physical-activity; Transportation Modes; Built Environment; Activity Spaces; Research Agenda; Risk-factors; Associations; Exposure
Nazari, Ahad; Vandadian, Shaghayegh; Abdirad, Hamid. (2017). Fuzzy AHP Model for Prequalification of Engineering Consultants in the Iranian Public Procurement System. Journal Of Management In Engineering, 33(2).
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Abstract
Prequalification of engineering consultants in the Iranian public procurement system is suffering from arbitrary processes and criteria that cannot effectively shortlist the increasing number of potential bidders. This study aims to develop a prequalification model that can serve as the basis for revising the existing regulations and criteria. The authors conducted interviews among experts to localize a framework of prequalification criteria. Fuzzy analytical hierarchy process (FAHP), accompanied by a survey among industry participants, was used to determine the importance level of decision criteria. The results confirmed that the existing guidelines cannot meet the expectations of the industry due to the overemphasis on the past performance of consultants and disregarding their current capabilities. For the international audience, this study clarifies that (1)the working culture of industry participants impacts their judgments on the importance level of intangible and tangible criteria used for prequalification processes, (2)short-listing consultants for long-term and fragmented data collection in national registration or project prequalification should be avoided, and (3)researchers must test FAHP models with different fuzzy scales because the success of the widely used fuzzy extent analysis method is highly dependent on the scale of fuzzy functions and judgments of decision makers.
Keywords
Analytic Hierarchy Process; Fuzzy Set Theory; Organisational Aspects; Procurement; Project Management; Public Relations; Tendering; Fuzzy Ahp Model; Project Prequalification Criteria; Iranian Public Procurement System; Bidders; Fuzzy Analytical Hierarchy Process; Industry Participants; International Audience; National Registration; Fuzzy Scales; Fuzzy Extent Analysis Method; Decision Makers; Engineering Consultants; Working Culture; Decision-making Model; Extent Analysis Method; Selection; Qualification; Contractors; Criteria; Consultants; Prequalification; Fuzzy; Analytical Hierarchy Process (ahp)
Dannenberg, Andrew L.; Burpee, Heather. (2018). Architecture for Health Is Not Just for Healthcare Architects. Health Environments Research & Design Journal (herd) (sage Publications, Ltd.), 11(2), 8 – 12.
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Keywords
Building Design & Construction; Public Health; Quality Of Life; Built Environment; Public Spaces
Mooney, Stephen J.; Lemaitre, Rozenn N.; Siscovick, David S.; Hurvitz, Philip; Goh, Charlene E.; Kaufman, Tanya K.; Zulaika, Garazi; Sheehan, Daniel M.; Sotoodehnia, Nona; Lovasi, Gina S. (2018). Neighborhood Food Environment, Dietary Fatty Acid Biomarkers, and Cardiac Arrest Risk. Health & Place, 53, 128 – 134.
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Abstract
We explored links between food environments, dietary intake biomarkers, and sudden cardiac arrest in a population-based longitudinal study using cases and controls accruing between 1990 and 2010 in King County, WA. Surprisingly, presence of more unhealthy food sources near home was associated with a lower 18:1 trans-fatty acid concentration ( - 0.05% per standard deviation higher count of unhealthy food sources, 95% Confidence Interval [CI]: 0.01, 0.09). However, presence of more unhealthy food sources was associated with higher odds of cardiac arrest (Odds Ratio [OR]: 2.29, 95% CI: 1.19, 4.41 per standard deviation in unhealthy food outlets). While unhealthy food outlets were associated with higher cardiac arrest risk, circulating 18:1 trans fats did not explain the association.
Keywords
Fatty Acids; Biological Tags; Cardiac Arrest; Food Contamination; Standard Deviations; Food Supply; Out-of-hospital Cardiac Arrest; Residence Characteristics; Sudden Cardiac Death; Trans Fatty Acids; New-york-city; Acute Myocardial-infarction; Low Socioeconomic-status; United-states; Vascular Inflammation; Cardiovascular Health; Older-adults; Death; Epidemiology; Arrhythmias; Dietary Supplements; Biomarkers; Heart Attacks; Risk Factors; Diet; Heart; Healthy Food; Fats; Dietary Intake; Food Sources; Food; Confidence Intervals; Biological Markers; Myocardial Infarction; Population Studies; Food Intake; Correlation Analysis; Neighborhoods
Acolin, Arthur; Goodman, Laurie; Wachter, Susan M. (2019). Accessing Homeownership with Credit Constraints. Housing Policy Debate, 29(1), 108 – 125.
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Abstract
The tightening of mortgage credit in the aftermath of the global financial crisis has been identified as a factor in the decline of homeownership in the United States to 50-year lows. In this article, we review findings about the role of borrowing constraints and tightened credit in lowering access to homeownership. We also discuss how institutional changes could hinder or support this access going forward.
Keywords
Borrowing Constraints; Home Ownership; Mortgage; Model; Race; Homeownership; Credit Access; International Finance; Economic Crisis; Property; Aftermath; Access; Credit; Access To Credit; Economic Models; United States--us
Jon, Ihnji. (2019). Resilience and ‘Technicity’: Challenges and Opportunities for New Knowledge Practices in Disaster Planning. Resilience-International Policies Practices and Discourses, 7(2), 107 – 125.
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Abstract
With increasing exposure to environmental catastrophes and natural hazards, the terminology of 'resilience' is becoming ubiquitous in the planning field. As a part of this continuing discussion, this paper examines how the concept of resilience has been used in disaster planning, especially with a focus on the creation and use of knowledge to 'build resilience' in response to potential future natural hazard events. In discussing the practice of creating and using knowledge in disaster planning, I draw insights from the interdisciplinary critical studies of science and technology literature, which has been developing rich discussions on the challenges we face in producing geographical knowledge. I demonstrate in this paper how resilience theory can be linked with the concept of 'technicity' used in the virtual geography literature, and how that association can have meaningful implications for the production and application of knowledge in disaster planning.
Keywords
Community Resilience; Adaptive Capacity; Vulnerability; Hazard; Risk; Sustainability; Participation; Geographies; Uncertainty; Complexity; Resilience; Technicity; Disaster Planning; Virtual Geography; Knowledge Practice
Pierobon, Francesca; Huang, Monica; Simonen, Kathrina; Ganguly, Indroneil. (2019). Environmental Benefits of Using Hybrid CLT Structure in Midrise Non-Residential Construction: An LCA Based Comparative Case Study in the U.S. Pacific Northwest. Journal Of Building Engineering, 26.
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Abstract
In this study, the cradle-to-gate environmental impact of a hybrid, mid-rise, cross-laminated timber (CLT) commercial building is evaluated and compared to that of a reinforced concrete building with similar functional characteristics. This study evaluates the embodied emissions and energy associated with building materials, manufacturing, and construction. Two alternative designs are considered for fire protection in the hybrid CLT building: 1) a 'fireproofing design', where gypsum wallboard is applied to the structural wood; and 2) a 'charring design', where two extra layers of CLT are added to the panel. The life cycle environmental impacts are assessed using TRACI 2.1 and the total primary energy is evaluated using the Cumulative Energy Demand impact method. Results show that an average of 26.5% reduction in the global warming potential is achieved in the hybrid CLT building compared to the concrete building, excluding biogenic carbon emissions. Except ozone depletion, where the difference in impact between scenarios is < 1%, replacing fireproofing with charring is beneficial for all impact categories. The embodied energy assessment of the building types reveals that, on average, the total primary energy in the hybrid CLT buildings and concrete building are similar. However, the non-renewable energy (fossil-based) use in the hybrid CLT building is 8% lower compared to that of the concrete building. As compared to the concrete building, additional 1,556 tCO(2)(e) and 2,567 tCO(2e) are stored in the wood components of the building (long-term storage of biogenic carbon) in the scenario with fireproofing and with charring, respectively.
Keywords
Wood; Concrete; Energy; Buildings; Impacts; Cross-laminated Timber; U.s. Pacific Northwest; Life Cycle Assessment; Cumulative Energy Demand; Biogenic Carbon; Carbon Storage
Adhikari, Pramodit; Mahmoud, Hussam; Xie, Aiwen; Simonen, Kathrina; Ellingwood, Bruce. (2020). Life-Cycle Cost and Carbon Footprint Analysis for Light-framed Residential Buildings Subjected to Tornado Hazard. Journal Of Building Engineering, 32.
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Abstract
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 multiobjective 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.
Keywords
Performance; Risk; Fragility; Residential Buildings; Life-cycle Analysis; Resilience; Optimal Decisions; Sustainable Construction; Tornadoes