scholarly journals Special-Length-Priority Algorithm to Minimize Reinforcing Bar-Cutting Waste for Sustainable Construction

2020 ◽  
Vol 12 (15) ◽  
pp. 5950
Author(s):  
Dongho Lee ◽  
Seunghyun Son ◽  
Doyeong Kim ◽  
Sunkuk Kim
Keyword(s):  
Co2 Emissions ◽  
Cost Savings ◽  
Construction Cost ◽  
Sustainable Construction ◽  
Unit Weight ◽  
Emissions Reduction ◽  
Reinforcing Bars ◽  
Minimization Method ◽  
Reinforcing Bar ◽  
Carbon Dioxide Co2

Reinforcing bars (rebar), which have the most embodied carbon dioxide (CO2) per unit weight in built environments, generate a significant amount of cutting waste during the construction phase. Excessive cutting waste not only increases the construction cost but also contributes to a significant amount of CO2 emissions. The objective of this paper is to propose a special-length-priority cutting waste minimization (CWM) algorithm for rebar, for sustainable construction. In the proposed algorithms, the minimization method by special and stock lengths was applied. The minimization by special length was performed first, and then the combination by stock length was performed for the remaining rebar. As a result of verifying the proposed algorithms through a case application, it was confirmed that the quantity of rebar was reduced by 6.04% compared with the actual quantity used. In the case building, a CO2 emissions reduction of 406.6 ton-CO2 and a cost savings of USD 119,306 were confirmed. When the results of this paper are applied in practice, they will be used as a tool for sustainable construction management as well as for construction cost reduction.

scholarly journals Cradle-to-Site Carbon Emissions Assessment of Prefabricated Rebar Cages for High-Rise Buildings in China

2018 ◽  
Vol 11 (1) ◽  
pp. 42 ◽  
Author(s):  
Boya Jiang ◽  
Hongxian Li ◽  
Ling Dong ◽  
Yu Wang ◽  
Yiqi Tao
Keyword(s):  
Co2 Emissions ◽  
Carbon Emissions ◽  
Sustainable Construction ◽  
The Sustainable Development ◽  
Reinforcing Bar ◽  
High Rise ◽  
Construction Methods ◽  
Three Stages ◽  
Material Preparation

Construction industrialization is growing rapidly and has received significant attention worldwide in recent years. The industrialization of construction results in several benefits, including the promotion of sustainable construction and the development and application of prefabrication techniques. The Prefabricated Rebar Cage (PRC) is an emerging solution applied to high-rise buildings as a replacement of the In-situ Reinforcing Bar (ISRB) construction method. This paper investigates the cradle-to-site carbon emissions of PRC, and compares the results with those of conventional in-situ rebar construction methods for high-rise buildings. The cradle-to-site cycle is divided into three stages, namely, material preparation, transportation, and on-site construction. For the material preparation stage, it is found that CO2 emissions are increased by 3% when using PRC due to the operation of machinery during the prefabrication process. In the transportation stage, CO2 emissions are found to increase by 3.3 times for PRC, as there is more transportation required for PRCs than for conventional construction methods. During the on-site construction stage, the PRC method demonstrates its advantages by reducing CO2 emissions by 44.7%, which is attributed to decreased hoisting frequency and lower mechanical utilization for fewer joining activities. Overall, CO2 emissions can be reduced by 1.24% by adopting the PRC method for high-rise buildings, and it is therefore recommended to adopt PRCs for this purpose. This research studies carbon emissions of PRC and contributes to promoting the sustainable development of prefabricated building techniques.

scholarly journals Empirical Explanations of Carbon Mitigation during Periods of Economic Growth

2019 ◽  
Author(s):  
Ranran Wang ◽  
Valentina A. Assenova ◽  
Edgar Hertwich
Keyword(s):  
Economic Growth ◽  
Co2 Emissions ◽  
Economic Efficiency ◽  
Low Income ◽  
Empirical Relationship ◽  
Energy System ◽  
Emissions Reduction ◽  
Emissions Reductions ◽  
Reduce Emissions ◽  
Carbon Dioxide Co2

Prior research on the empirical relationship between anthropogenic carbon dioxide (CO2) emissions and economic growth, as measured by increases in gross domestic product (GDP), indicate that a 1% growth in GDP can lead to anything between an increase in emissions by 2.5% to a decline by 0.3%. Studies have paid little attention to independent mechanisms that reduce emissions. Statistical properties of the data undermine the estimation techniques used in many studies. To address these shortcomings, we used novel methods and panel data integrating emissions, economic, and energy-system characteristics across 70 economies over 1970-2013 to derive a universal GDP-emissions relationship and identify key emissions-reduction mechanisms. We found that, robust to a variety of estimation procedures, every 1% increase in GDP was associated with a 1% increase in CO2 emissions when controlling for other mechanisms. Emissions reductions were mainly driven by four mechanisms: (i) energy system decarbonization, (ii) increased economic efficiency, (iii) electrification, and (iv) deindustrialization. A 1% increase in these factors was associated with 0.2-1.8% reductions in CO2 emissions per year; together, these factors contributed to 18 petagrams of emissions reduction globally over 1970-2013. Decarbonization contributed most to emissions reductions in high-income economies, while economic efficiency and electrification contributed most to reductions in low-income economies.

scholarly journals The impact of COVID-19 on CO2 emissions in the Los Angeles and Washington DC/Baltimore metropolitan areas 

2021 ◽  
Author(s):  
Anna Karion ◽  
Vineet Yadav ◽  
Subhomoy Ghosh ◽  
Kimberly Mueller ◽  
Geoffrey Roest ◽  
...  
Keyword(s):  
Los Angeles ◽  
Co2 Emissions ◽  
Atmospheric Co2 ◽  
Emissions Reduction ◽  
Washington Dc ◽  
Gas Consumption ◽  
Model Dependency ◽  
Carbon Dioxide Co2 ◽  
Urban Emissions ◽  
The Impact

<div> <div> <div> <p>Responses to COVID-19 have resulted in unintended reductions of city-scale carbon dioxide (CO2) emissions. Here we detect and estimate decreases in CO2 emissions in Los Angeles and Washington DC/Baltimore during March and April 2020. Our analysis uses three lines of evidence with increasing model dependency. The first detects the timing of emissions declines using the variability in atmospheric CO2 observations, the second assesses the continuation of reduced emissions using CO2 enhancements, and the third employs an inverse model to estimate the relative emissions changes in 2020 compared to 2018 and 2019. Emissions declines began in mid-March in both cities. The March decrease (25%) in Washington DC/Baltimore is largely supported by a drop in natural gas consumption associated with a warm spring whereas the decrease in April (33%) correlates with changes in gasoline fuel sales, a proxy for vehicular emissions. In contrast, only a fraction of the March (17%) and April (34%) reduction in Los Angeles is explained by traffic declines, while the remainder of the emissions reduction remains unexplained. To help diagnose such observed changes in emissions, more reliable, publicly available emission information from all significant sectors needs to be made available. Methods and measurements used herein highlight the advantages of atmospheric CO2 observations for providing timely insights into rapidly changing urban emissions patterns that can empower cities to course-correct mitigation activities more efficiently.</p> </div> </div> </div>

scholarly journals Estimating the Potential of Electric Vehicles for Travelling to Work and Education in Melbourne, Victoria

2021 ◽  
Vol 1 (3) ◽  
pp. 737-746
Author(s):  
Mahmut Gezmish ◽  
Long T. Truong
Keyword(s):  
Carbon Dioxide ◽  
Co2 Emissions ◽  
Electric Vehicles ◽  
Operating Cost ◽  
Cost Savings ◽  
Average Operating ◽  
Carbon Dioxide Co2 ◽  
Car Travel

This paper aims to estimate the potential of electric vehicles (EVs) in Melbourne, Victoria, using the Victorian Integrated Survey of Travel and Activity (VISTA) data. The investigation of whether EVs with different all-electric ranges (AERs) can replace car travel to work and education is the focus of this paper. The results showed that EVs would be able to replace most car travel to work (68.5% to 97.1%) and car travel to education (71.9% to 96.9%), with AERs increasing from 40 km to 100 km, assuming car drivers are willing to use an EV. It is estimated that the average operating cost savings per person would be up to AUD 3.12 and AUD 2.79 each day, regarding travel to work and education, respectively. Considering both travel to work and education, EVs could replace up to 33.8 million kilometres of car travel, consuming around 7.6 GWh and resulting in a reduction in carbon dioxide (CO2) emissions of about 610 tons each day.

scholarly journals Opportunities and Challenges of Green-Lean: An Integrated System for Sustainable Construction

2020 ◽  
Vol 12 (11) ◽  
pp. 4460 ◽  
Author(s):  
Mohammadsoroush Tafazzoli ◽  
Ehsan Mousavi ◽  
Sharareh Kermanshachi
Keyword(s):  
Cost Savings ◽  
Integrated Approach ◽  
Integrated System ◽  
Waste Minimization ◽  
Sustainable Construction ◽  
Future Research ◽  
Safety Improvement ◽  
The Individual ◽  
High Level ◽  
Industry Professionals

Although the two concepts of lean and sustainable construction have been developed due to different incentives, and they do not pursue the same exact goals, there exists considerable commonality between them. This paper discusses the potentials for integrating the two approaches and their practices and how the resulting synergy from combining the two methods can potentially lead to higher levels of fulfilling the individual goals of each of them. Some limitations and challenges to implementing the integrated approach are also discussed. Based on a comprehensive review of existing papers related to sustainable and lean construction topics, the commonality between the two approaches is discussed and grouped in five categories of (1) cost savings, (2) waste minimization, (3) Jobsite safety improvement, (4) reduced energy consumption, and (5) customers’ satisfaction improvement. The challenges of this integration are similarly identified and discussed in the four main categories of (1) additional initial costs to the project, (2) difficulty of providing specialized expertise, (3) contractors’ unwillingness to adopt the additional requirements, and (4) challenges to establish a high level of teamwork. Industry professionals were then interviewed to rank the elements in each of the two categories of opportunities and challenges. The results of the study highlight how future research can pursue the development of a new Green-Lean approach by investing in the communalities and meeting the challenges of this integration.

scholarly journals Study on the Bending and Joint Performances of Reinforced Concrete Beams Using High-Strength Rebars

2021 ◽  
Vol 13 (6) ◽  
pp. 3482
Author(s):  
Seoungho Cho ◽  
Myungkwan Lim ◽  
Changhee Lee
Keyword(s):  
Yield Strength ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
High Yield ◽  
Performance Tests ◽  
Reinforcing Bars ◽  
Joint Performance ◽  
Lap Splice ◽  
Reinforcing Bar ◽  
Nominal Strength

High-strength reinforcing bars have high yield strengths. It is possible to reduce the number of reinforcing bars placed in a building. Accordingly, as the amount of reinforcement decreases, the spacing of reinforcing bars increases, workability improves, and the construction period shortens. To evaluate the structural performance of high-strength reinforcing bars and the joint performance of high-strength threaded reinforcing bars, flexural performance tests were performed in this study on 12 beam members with the compressive strength of concrete, the yield strength of the tensile reinforcing bars, and the tensile reinforcing bar ratio as variables. The yield strengths of the tensile reinforcement and joint methods were used as variables, and joint performance tests were performed for six beam members. Based on this study, the foundation for using high-strength reinforcing bars with a design standard yield strength equal to 600 MPa was established. Accordingly, mechanical joints of high-strength threaded reinforcing bars (600 and 670 MPa) can be used. All six specimens were destroyed under more than the expected nominal strength. Lap splice caused brittle fractures because it was not reinforced in stirrup. Increases of 21% to 47% in the loads of specimens using a coupler and a lock nut were observed. Shape yield represents destruction—a section must ensure sufficient ductility after yielding. Therefore, a coupler and lock nut are effective.

Measuring energy and environmental efficiency interactions towards CO2 emissions reduction without slowing economic growth in central and western Europe

2021 ◽  
Vol 279 ◽  
pp. 111704
Author(s):  
Jijian Zhang ◽  
Ataul Karim Patwary ◽  
Huaping Sun ◽  
Muhammad Raza ◽  
Farhad Taghizadeh-Hesary ◽  
...  
Keyword(s):  
Economic Growth ◽  
Co2 Emissions ◽  
Western Europe ◽  
Environmental Efficiency ◽  
Emissions Reduction
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