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  • 1.
    Chen, Shiwei
    et al.
    Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    Feng, Kailun
    Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    A Simulation-Based Optimisation for Contractors in Precast Concrete Projects2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Purpose

    This paper aims to provide decision support for precast concrete contractors about both precastconcrete supply chain strategies and construction configurations.

    Design/Methodology/Approach

    This paper proposes a simulation-based optimisation for supplychain and construction (SOSC) during the planning phase of PC building projects. The discrete eventsimulation is used to capture the characteristics of supply chain and construction processes, and calculate construction objectives under different plans. Particle swarm optimisation is combined with simulation tofind optimal supply chain strategies and construction configurations.

    Findings

    The efficiency of SOSC is compared with the parametric simulation approach. Over 70 per centof time and effort used to simulate and compare alternative plans is saved owing to SOSC.

    Research Limitations/Implications

    Building simulation model costs a lot of time and effort. The data requirement of the proposed method is high.

    Practical Implications

    The proposed SOSC approach can provide decision support for PC contractorsby optimising supply chain strategies and construction configurations.

    Originality/Value

    This paper has two contributions: one is in providing a decision support tool SOSC tooptimise both supply chain strategies and construction configurations, while the other is in building aprototype of SOSC and testing it in a case study.

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  • 2.
    Chen, Shiwei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Dept. of Construction Management, Harbin Institute of Technology, Harbin 150000, China.
    Feng, Kailun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Dept. of Construction Management, Harbin Institute of Technology, Harbin 150000, China.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Wang, Yaowu
    Construction Management, Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology, Harbin Institute of Technology, Harbin, China 150000.
    Chen, Xue
    Construction Management, Harbin Institute of Technology, Harbin, China 150000.
    Wang, Shuo
    Zhonghuan Information College, Tianjin Univ. of Technology, Tianjin 300380, China.
    A Discrete Event Simulation-Based Analysis of Precast Concrete Supply Chain Strategies Considering Suppliers’ Production and Transportation Capabilities2019Ingår i: ICCREM 2019: Innovative Construction Project Management and Construction Industrialization: Proceedings of the International Conference on Construction and Real Estate Management 2019 / [ed] Yaowu Wang; Mohamed Al-Hussein; Geoffrey Q. P. Shen, American Society of Civil Engineers (ASCE), 2019, s. 12-24Konferensbidrag (Refereegranskat)
    Abstract [en]

    The production and transportation capabilities of a precast concrete (PC) component supplier have great impact on the construction of a PC building project. In China, the production and transportation capabilities of different PC suppliers can vary greatly, which will influence contractors’ selection of PC supply chain strategies. However, previous studies often considered the capabilities of PC suppliers to be ideal and failed to compare different PC supply chain strategies under different levels of suppliers capabilities. This study collects detailed data from a PC building project and uses discrete event simulation (DES) to compare different supply chain strategies under different production and transportation capability levels of PC suppliers. Construction duration, construction cost, and greenhouse gas emissions are selected as indicators to compare three different supply chain strategies: just-in-time, on-site storage, and off-site storage. The strengths and weaknesses of each strategy under different capabilities of PC suppliers are found. The results provides guidance for contractors in selecting supply chain strategies when considering PC suppliers’ production and transportation capabilities.  

  • 3.
    Chen, Shiwei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Dehghanimohammadabadi, Mohammad
    Northeastern University, Boston.
    Emborg, Mats
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Nilimaa, Jonny
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Wang, Yaowu
    Harbin Institute of Technology.
    Kailun, Feng
    Harbin Institute of Technology.
    Concrete Construction: How to Explore Environmental and Economic Sustainability in Cold Climates2020Ingår i: Sustainability, E-ISSN 2071-1050, Vol. 12, nr 9, artikel-id 3809Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In many cold regions around the world, such as northern China and the Nordic countries,on‐site concrete is often cured in cold weather conditions. To protect the concrete from freezing or excessively long maturation during the hardening process, contractors use curing measures. Different types of curing measures have different effects on construction duration, cost, and greenhouse gas emissions. Thus, to maximize their sustainability and financial benefits, contractors need to select the appropriate curing measures against different weather conditions. However, there is still a lack of efficient decision support tools for selecting the optimal curing measures, considering the temperature conditions and effects on construction performance. Therefore, the aim of this study was to develop a Modeling‐Automation‐Decision Support (MADS) framework and tool to help contractors select curing measures to optimize performance in terms of duration, cost, and CO2 emissions under prevailing temperatures. The developed framework combines a concrete maturity analysis (CMA) tool, a discrete event simulation (DES), and a decision support module to select the best curing measures. The CMA tool calculates the duration of concrete curing needed to reach the required strength, based on the chosen curing measures and anticipated weather conditions. The DES simulates all construction activities to provide input for the CMA and uses the CMA results to evaluate construction performance. To analyze the effectiveness of the proposed framework, a software prototype was developed and tested on a case study in Sweden. The results show that the developed framework can efficiently propose solutions that significantlyreduce curing duration and CO2 emissions.

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  • 4.
    Erikshammar, Jarkko
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Alestig, Erik
    Prolog AB.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Parametric Value Stream Mapping Framework: A Case Study of a Small Swedish Industrialized House-Building Supplier2014Ingår i: Proceedings of IGLC22: 22nd Annual Conference of the International Group for Lean Consruction : understanding and improving project based production / [ed] Bo Terje Kalsaas; Lauri Koskela; Tarcisio Abreu Saurin, Oslo, Norway: Akademika forlag, 2014, Vol. 1, s. 425-436Konferensbidrag (Refereegranskat)
    Abstract [en]

    Industrialized house-building is based on repetitive processes used in the supply, design, manufacturing and erection of pre-configured houses. Industrialized house-building contractors are dependent on many small suppliers and sub-contractors in their supply chain. These small suppliers, with limited resources and capabilities, need to be able to develop products and processes in order to deliver future customer value without wasting development resources on non-viable products. Our question is whether product development by small and medium-sized (SME) industrialized house-building suppliers could be supported by parametric Value Stream Mapping.The objective is to explore a process design framework in which Value stream Mapping (VSM) is used to identify improvements and to generate product development suggestions, based on a set of parameters defined as P1, P2..., Pn.The testing was carried out at a Swedish SME supplier to the industrialized house-building sector, using a newly-developed roofing board with an integrated membrane, with the parameters (P1) customer needs, (P2) waste on construction site and (P3) construction worker safety. Data were collected using interviews and video-recorded participant observations on two construction sites. Findings indicate that VSM cannot describe attributes of a product other than those associated with production flow. However, parametric VSM helped the case study company to stop current development and instead suggest valuable product attributes. The implications are that parametric VSM enhances the application of VSM. Parametric VSM can be used by SME suppliers as an input to product development in order to validate product attributes before launch. However, this is based on a single case study and further research is needed.

  • 5.
    Erikshammar, Jarkko
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Discrete Event Simulation Enhanced Value Stream Mapping: An Industrialized Construction Case Study2013Ingår i: Lean Construction Journal, E-ISSN 1555-1369, Vol. 10, s. 47-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research Question/Hypothesis: Can a production process design framework created by integrating Value Stream Mapping (VSM) and Discrete Event Simulation (DES) be used to assess the production system performance, as predicted by a future state design of small and medium sized enterprises (SMEs) working in industrialized construction?

    Purpose: To explore a production process design framework in which VSM is used to identify doable improvements and DES provides analytical evaluation of them.

    Research Method: The demonstration was carried out at a Swedish SME industrialized construction component manufacturer

    Findings: VSM is unable to evaluate analytically the performance of the future state design. This inability leads to unnecessary implementation iterations. VSM assumes a deterministic model and cannot describe the dynamic behaviors of a system. The dynamic behavior of the construction processes will result in the future state design not performing as expected. However, by analytically evaluating the future state with DES helped the case company to implement a new production process design.

    Limitations: DES modeling is still time-consuming and needs skilled professionals, the cost of whom can be prohibitive for SMEs and demonstrated in one case study.

    Implications: The integration of DES and VSM provides a framework to evaluate and communicate the outcome, hence enhancing the application of VSM.

    Value for practitioners: A lean framework, which can be used, for industrialized construction processes especially by SMEs with very limited resources, to validate changes before implementing them.

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  • 6.
    Feng, Kailun
    et al.
    Harbin Institute of Technology Resources Engineering, Harbin, CHINA.
    Chen, Shiwei
    Harbin Institute of Technology Resources Engineering, Harbin, CHINA.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Machine learning based construction simulation and optimization2018Ingår i: Proceedings of the 2018 Winter Simulation Conference / [ed] M. Rabe; A.A. Juan; N. Mustafee; A. Skoogh; S. Jain; B. Johansson, IEEE, 2018, s. 2025-2036, artikel-id 8632290Konferensbidrag (Refereegranskat)
    Abstract [en]

    Building construction comprises interaction and interdependence among processes. Discrete-event simulation (DES) is widely applied to model these processes interaction. To find optimal construction plans, optimization technique is usually integrated with DES. However, present simulation-optimization integrated method directly invokes simulation model within optimization algorithms, which is found significantly computationally expensive. This study proposes a machine learning based construction simulation and optimization integrated method. After trained by DES, the machine learning model accelerates simulation-optimization integration by nearly real-time providing fitness evaluation within optimization. This method was implemented into a real construction project for construction time-cost-environment optimization. Results show that proposed machine learning based method significantly reduce computing time compared with original simulation-optimization integration. Less than 1% of construction cost and time improvement were miss, while greenhouse gas emissions obtained same performance. The new method could be a more effective DES and optimization integration approach for practical engineering application.

  • 7.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Construction Management, Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, Harbin, China; Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology, Harbin Institute of Technology, Harbin, China.
    Chen, Shiwei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Wang, Shuo
    Department of Construction Management, Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, Harbin, China; Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology, Harbin Institute of Technology, Harbin, China.
    Yang, Bin
    School of Energy and Safety Engineering, Tianjin Chengjian University, Tianjin, China; Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Sun, Chengshuang
    School of Urban Economics and Management, Beijing University of Civil Engineering and Architecture, Beijing, China.
    Wang, Yaowu
    Department of Construction Management, Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, Harbin, China; Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology, Harbin Institute of Technology, Harbin, China.
    Embedding ensemble learning into simulation-based optimisation: a learning-based optimisation approach for construction planning2023Ingår i: Engineering Construction and Architectural Management, ISSN 0969-9988, E-ISSN 1365-232X, Vol. 30, nr 1, s. 259-295Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose - Simulation-based optimisation (SO) is a popular optimisation approach for building and civil engineering construction planning. However, in the framework of SO, the simulation is continuously invoked during the optimisation trajectory, which increases the computational loads to levels unrealistic for timely construction decisions. Modification on the optimisation settings such as reducing searching ability is a popular method to address this challenge, but the quality measurement of the obtained optimal decisions, also termed as optimisation quality, is also reduced by this setting. Therefore, this study aims to develop an optimisation approach for construction planning that reduces the high computational loads of SO and provides reliable optimisation quality simultaneously.

    Design/methodology/approach - This study proposes the optimisation approach by modifying the SO framework through establishing an embedded connection between simulation and optimisation technologies. This approach reduces the computational loads and ensures the optimisation quality associated with the conventional SO approach by accurately learning the knowledge from construction simulations using embedded ensemble learning algorithms, which automatically provides efficient and reliable fitness evaluations for optimisation iterations.

    Findings - A large-scale project application shows that the proposed approach was able to reduce computational loads of SO by approximately 90%. Meanwhile, the proposed approach outperformed SO in terms of optimisation quality when the optimisation has limited searching ability.

    Originality/value - The core contribution of this research is to provide an innovative method that improves efficiency and ensures effectiveness, simultaneously, of the well-known SO approach in construction applications. The proposed method is an alternative approach to SO that can run on standard computing platforms and support nearly real-time construction on-site decision-making.

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  • 8.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Chen, Shiwei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Wang, Shuo
    Department of Construction Management, Harbin Institute of Technology.
    Yang, Bin
    Department of Applied Physics and Electronics, Umeå University.
    Sun, Chengshuang
    Beijing University of Civil Engineering and Architecture.
    Wang, Yaowu
    Department of Construction Management, Harbin Institute of Technology.
    Embedding Ensemble Learning into Construction Optimisation: A Computational Reduction Approach2020Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Simulation-based optimisation (SO), which combines simulation and optimisation technologies, is a popular approach for construction planning optimisation. However, in the framework of SO, the simulation is continuously invoked during the optimisation trajectory, which increases the computing loads to levels that are unrealistic to support the real-time construction decision. This study proposes ensemble learning embedded simulation optimisation (ESO) as an alternative approach for construction optimisation. The ensemble learning (EL) algorithm modifies the SO framework through establishing a connection between the simulation and optimisation technologies. This approach reduces the computing loads associated with the conventional SO framework by accurately learning from simulations and providing efficient fitness evaluations for optimisation. A large-scale project application shows that the proposed approach was able to reduce the computing loads of SO by approximately 90% yet still provide comparable optimisation quality. The proposed method is an alternative approach to SO that can be run on standard computing platforms and supports nearly real-time optimisation decisions.

  • 9.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Chen, Shiwei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    Wang, Yaowu
    Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    An Integrated Environment–Cost–Time Optimisation Method for Construction Contractors Considering Global Warming2018Ingår i: Sustainability, E-ISSN 2071-1050, Vol. 10, nr 11, artikel-id 4207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction contractors play a vital role in reducing the environmental impacts during the construction phase. To mitigate these impacts, contractors need to develop environmentally friendly plans that have optimal equipment, materials and labour configurations. However, construction plans with optimal environment may negatively affect the project cost and duration, resulting in dilemma for contractors on adopting low impacts plans. Moreover, the enumeration method that is usually used needs to assess and compare the performances of a great deal of scenarios, which seems to be time consuming for complicated projects with numerous scenarios. This study therefore developed an integrated method to efficiently provide contractors with plans having optimal environment-cost-time performances. Discrete-event simulation (DES) and particle swarm optimisation algorithms (PSO) are integrated through an iterative loop, which remarkably reduces the efforts on optimal scenarios searching. In the integrated method, the simulation module can model the construction equipment and materials consumption; the assessment module can evaluate multi-objective performances; and the optimisation module fast converges on optimal solutions. A prototype is developed and implemented in a hotel building construction. Results show that the proposed method greatly reduced the times of simulation compared with enumeration method. It provides the contractor with a trade-off solution that can average reduce 26.9% of environmental impact, 19.7% of construction cost, and 10.2% of project duration. The method provides contractors with an efficient and practical decision support tool for environmentally friendly planning.

  • 10.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Construction Management, Harbin Institute of Technology, Harbin, 150001, China.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Chen, Shiwei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Department of Construction Management, Harbin Institute of Technology, Harbin, 150001, China.
    Yan, Hui
    School of Civil Engineering and Transportation, South China University of Technology, Guangzhou, 510641, China.
    Wang, Yaowu
    Harbin Institute of Technology, Information Technology Institute, Harbin, China.
    A predictive environmental assessment method for construction operations: Application to a Northeast China case study2018Ingår i: Sustainability, E-ISSN 2071-1050, Vol. 10, nr 11, artikel-id 3868Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction accounts for a considerable number of environmental impacts, especially in countries with rapid urbanization. A predictive environmental assessment method enables a comparison of alternatives in construction operations to mitigate these environmental impacts. Process-based life cycle assessment (pLCA), which is the most widely applied environmental assessment method, requires lots of detailed process information to evaluate. However, a construction project usually operates in uncertain and dynamic project environments, and capturing such process information represents a critical challenge for pLCA. Discrete event simulation (DES) provides an opportunity to include uncertainty and capture the dynamic environments of construction operations. This study proposes a predictive assessment method that integrates DES and pLCA (DES-pLCA) to evaluate the environmental impact of on-site construction operations and supply chains. The DES feeds pLCA with process information that considers the uncertain and dynamic environments of construction, while pLCA guides the comprehensive procedure of environmental assessment. A DES-pLCA prototype was developed and implemented in a case study of an 18-storey building in Northeast China. The results showed that the biggest impact variations on the global warming potential (GWP), acidification potential (AP), eutrophication (EP), photochemical ozone creation potential (POCP), abiotic depletion potential (ADP), and human toxicity potential (HTP) were 5.1%, 4.1%, 4.1%, 4.7%, 0.3%, and 5.9%, respectively, due to uncertain and dynamic factors. Based on the proposed method, an average impact reduction can be achieved for these six indictors of 2.5%, 21.7%, 8.2%, 4.8%, 32.5%, and 0.9%, respectively. The method also revealed that the material wastage rate of formwork installation was the most crucial managing factor that influences global warming performance. The method can support contractors in the development and management of environmentally friendly construction operations that consider the effects of uncertainty and dynamics.

  • 11.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Wang, Yaowu
    Department of Construction Management, Harbin Institute of Technology, Harbin, China. Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, Harbin, China. Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology, Harbin Institute of Technology, Harbin, China.
    Assessing environmental performance in early building design stage: An integrated parametric design and machine learning method2019Ingår i: Sustainable cities and society, ISSN 2210-6707, Vol. 50, artikel-id 101596Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Decisions made at early design stage have major impacts on buildings’ life-cycle environmental performance. However, when only a few parameters are determined in early design stages, the detailed design decisions may still vary significantly. This may cause same early design to have quite different environmental impacts. Moreover, default settings for unknown detailed design parameters clearly cannot cover all possible variations in impact, and Monte Carlo analysis is sometimes not applicable as parameters’ probability distributions are usually unknown. Thus, uncertainties about detailed design make it difficult for existing environmental assessment methods to support early design decisions.

    Thus, this study developed a quantitative method using parametric design technology and machine learning algorithms for assessing buildings’ environmental performance in early decision stages, considering uncertainty associated with detailed design decisions. The parametric design technology creates design scenarios dataset, then associated environmental performances are assessed using environmental assessment databases and building performance simulations. Based on the generated samples, a machine learning algorithm integrating fuzzy C-means clustering and extreme learning machine extracts the case-specific knowledge regarding designed buildings’ early design associated with environmental uncertainty. Proposed method is an alternative but more generally applicable method to previous approaches to assess building's environmental uncertainty in early design stages.

  • 12.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Wang, Shuo
    Department of Construction Management, Harbin Institute of Technology.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Uncertainty Analysis Approach for Construction under Deep Uncertainty2020Ingår i: Journal of construction engineering and management, ISSN 0733-9364, E-ISSN 1943-7862Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction processes usually occur under uncertain conditions, such as uncertain labour work productivity, equipment failure rate, weather situation and off-site transport condition. These uncertain factors can significantly affect project outcomes. However, for projects lacking a full understanding of uncertain factors, uncertainty analysis approaches relying on prior probability distribution or reasonable range are no longer applicable. Situations in which uncertain factors cannot be fully understood in decision-making are defined as deep uncertainty problems.

    This study proposes an uncertainty analysis approach that integrates process simulation and data mining to be a data-driven method for decision-making in construction projects under deep uncertainty. In process simulation, a Latin Hypercube Sampling (LHS) generates the samples of uncertainty scenario, and Discrete-Event Simulation (DES) quantifies robustness of alternative schemes under uncertain scenarios. In data mining, the Patient Rule Induction Method (PRIM) algorithm reveals the vulnerability of decisions that lead to unacceptable project performance. A real construction case was used to test the presented approach, with the results revealing that the approach is valuable for decision-makers who need to analyse uncertainty without reliable prior probability distributions and reasonable range of certain uncertain factors. It quantified the robustness of various construction schemes, as well as identified the vulnerable scenarios that could jeopardise project completion. The developed approach is an applicable uncertainty analysis approach to support decision-making of construction project under deep uncertainty.

  • 13.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Construction Management, Harbin Institute of Technology.
    Wang, Yaowu
    Department of Construction Management, Harbin Institute of Techn.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    The Environmental Performance of Prefabricated Building and Construction: A Critical Review2017Ingår i: ICCREM 2017: Project Management and Construction Technology : Proceedings of the International Conference on Construction and Real Estate Management 2017 / [ed] Yaowu Wang, Yongshi Pang, Geoffrey Q. P. Shen, and Yimin Zhu,, American Society of Civil Engineers (ASCE), 2017, s. 18-42Konferensbidrag (Refereegranskat)
    Abstract [en]

    The building industry consumes a large amount of nature resources and generates significant environment impacts around the world. To mitigate the resource consumption and associated environmental impacts, prefabricated building and construction has been proven to be one of the solutions. Several studies have been published in the past decade to explore the potential environmental benefits of prefabrication. However, a systematic and holistic review in the context of environmental impacts of prefabrication is still lacking. The research aims to reveal state-of-the-art and identify the research trends regarding environmental performance of prefabricated building and construction. To do so, a 4-stage literature retrieval and integrated analysis framework is designed to efficiently capture and examine the subject of interest. The results revealed that the most focused research subjects in this field are environmental and energy performances assessment, and carbon and energy are most used metrics to evaluate these performances. Almost all reviewed research demonstrated that prefabrication was better than conventional building on environmental performance. Nevertheless, the most frequently used assessment method is process based life cycle assessment developed from previous conventional building analysis, which may not be the proper method for prefabrication building. Operation, maintenance, and demolition obtain less study attention and it may worsen the final decision. Present data source that usually based on other research may invalid the final results. The revealed trends and gaps can serve as in-depth information and motivation for researchers to make further progress in prefabricated building study

  • 14.
    Feng, Kailun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Wang, Yaowu
    Harbin Institute of Technology.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Li, Xiaodong
    Department of Construction Management, Harbin Institute of Technology.
    Weakness of Embodied Energy Assessment on Construction: A Literature Review2016Ingår i: ICCREM 2016: BIM Applications and offsite construction : Proceedings of the 2016 International Conference on Construction and Real Estate Management / [ed] Yaowu Wang, Mohamed Al-Hussein. Geoffrey Q. P. Shen, Yimin Zhu, American Society of Civil Engineers (ASCE), 2016, s. 547-559Konferensbidrag (Refereegranskat)
    Abstract [en]

    Construction industry consumes a large amount of energy and resources in both developed and developing countries. The opportunities for improving energy efficiency of construction could be research considering energy assessment and thereby providing suggestions for practical action. The research on embodied energy (EE) is an important endeavor of this orientation. The aim of this review paper is to investigate and analyze research weakness of present embodied energy study on construction. To do so, a professional searching tool called Academic 2.0 was employed to collect relevant publications from multiple databases in this research field. After obtaining relevant studies, paper elimination and information collection are performed based on predefined criteria. Data analysis was then performed and showed that assessment method, data sources, and research boundary differed dramatically amongst present study. And, they are weaknesses of current study. These results could help researchers deeply understand present study weakness and then overcome it in further study

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  • 15.
    Haller, Martin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Jansson, Gustav
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    An indicator for superfluous iteration in offsite building design processes2015Ingår i: Architectural Engineering and Design Management, ISSN 1745-2007, E-ISSN 1752-7589, Vol. 11, nr 5, s. 360-375Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Enhancement of iteration management in the design phase is important for successful offsite building projects. Design iteration has two aspects. Although iteration is necessary to deal with design requirements when solving complex problems (i.e. increasing quality through iteration), it has also been identified in numerous studies to be one of the main causes of design errors and time and cost overruns (i.e. superfluous iteration), as it increases scheduling and design complexity. Current building project management tools do not provide a means to control the reduction of superfluous iteration. One problem is that existing research has difficulty precisely relating the effects of specific management actions to superfluous iteration. The idea of this study is to develop an indicator, the sequence deviation quotient (SDQ), which reflects the amount of superfluous design iteration in a project. It can be thought of as a tool supporting project managers to make systematic and continuous (from project to project) design process improvement. A premise is that the impact of varying project conditions on the process structure of design processes, i.e. the precedence relationships between the design activities, is only small. In this paper, we provide a definition of superfluous iteration. We tested the feasibility of the SDQ by subjecting it to project variation and input perturbation by means of a Monte Carlo simulation. The simulations are based on the data from a real offsite design building process, the designing of a 1100 m2 residential building in Sweden.

  • 16.
    Jassim, Hassanean
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Krantz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    A Cradle-to-Gate Framework for Optimizing Material Production in Road Construction2016Ingår i: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, nr 19, s. 758-764Konferensbidrag (Refereegranskat)
    Abstract [en]

    Abstract

    In road construction, large quantities of raw materials are extracted and transported duringseveral stages of its life cycle. Consequently, processing and preparation of raw materials fordifferent purposes inevitably result in considerable amount of energy use and emissions of airpollutants. The Swedish Transportation Administration has an ambition to minimizeenvironmental impacts from transport infrastructure projects by, for instance, reducing the energyuse and emissions of greenhouse gases. This can be achieved by implementing specific strategiesand techniques during various stages throughout the life cycle of the project. In this paper aframework is proposed to manage the energy use and greenhouse gases emissions from rawmaterials extraction processes in road construction projects. A prototype is developed based onthe framework and demonstrated in a small case study.

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  • 17.
    Jassim, Hassanean
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Civil Engineering, College of Engineering, University of Babylon, Babylon, Iraq.
    Krantz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    A Model to Reduce Earthmoving Impacts2020Ingår i: Journal of Civil Engineering and Management, ISSN 1392-3730, E-ISSN 1822-3605, Vol. 26, nr 6, s. 490-512Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Meeting increasingly ambitious carbon regulations in the construction industry is particularly challenging for earthmoving operations due to the extensive use of heavy-duty diesel equipment. Better planning of operations and balancing of competing demands linked to environmental concerns, costs, and duration is needed. However, existing approaches (theoretical and practical) rarely address all of these demands simultaneously, and are often limited to parts of the process, such as earth allocation methods or equipment allocation methods based on practitioners’ past experience or goals. Thus, this study proposes a method that can integrate multiple planning techniques to maximize mitigation of project impacts cost-effectively, including the noted approaches together with others developed to facilitate effective decision-making. The model is adapted for planners and contractors to optimize mass flows and allocate earthmoving equipment configurations with respect to tradeoffs between duration, cost, CO2 emissions, and energy use. Three equipment allocation approaches are proposed and demonstrated in a case study. A rule-based approach that allocates equipment configurations according to hauling distances provided the best-performing approach in terms of costs, CO2 emissions, energy use and simplicity (which facilitates practical application at construction sites). The study also indicates that trucks are major contributors to earthmoving operations’ costs and environmental impacts.

  • 18.
    Jassim, Hassanean
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Determining the environmental impact of material hauling with wheel loaders during earthmoving operations2019Ingår i: Journal of the Air and Waste Management Association, ISSN 1096-2247, E-ISSN 2162-2906, Vol. 69, nr 10, s. 1195-1214Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A method has been developed to estimate the environmental impact of wheel loaders used in earthmoving operations. The impact is evaluated in terms of energy use and emissions of air pollutants (CO2, CO, NOx, CH4, VOC, and PM) based on the fuel consumption per cubic meter of hauled material. In addition, the effects of selected operational factors on emissions during earthmoving activities were investigated to provide better guidance for practitioners during the early planning stage of construction projects. The relationships between six independent parameters relating to wheel loaders and jobsite conditions (namely loader utilization rates, loading time, bucket payload, horsepower, load factor, and server capacity) were analyzed using artificial neural networks, machine performance data from manufacturer’s handbooks, and discrete event simulations of selected earthmoving scenarios. A sensitivity analysis showed that the load factor is the largest contributor to air pollutant emissions, and that the best way to minimize environmental impact is to maximize the wheel loaders’ effective utilization rates. The new method will enable planners and contractors to accurately assess the environmental impact of wheel loaders and/or hauling activities during earthmoving operations in the early stages of construction projects.

    Implications: There is an urgent need for effective ways of benchmarking and mitigating emissions due to construction operations, and particularly those due to construction equipment, during the pre-construction phase of construction projects. Artificial Neural Networks (ANN) are shown to be powerful tools for analyzing the complex relationships that determine the environmental impact of construction operations and for developing simple models that can be used in the early stages of project planning to select machine configurations and work plans that minimize emissions and energy consumption. Using such a model, it is shown that the fuel consumption and emissions of wheel loaders are primarily determined by their engine load, utilization rate, and bucket payload. Moreover, project planners can minimize the environmental impact of wheel loader operations by selecting work plans and equipment configurations that minimize wheel loaders’ idle time and avoid bucket payloads that exceed the upper limits specified by the equipment manufacturer.

  • 19.
    Jassim, Hassanean
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Predicting energy consumption and CO2 emissions of excavators in earthwork operations: An artificial neural network model2017Ingår i: Sustainability, E-ISSN 2071-1050, Vol. 9, nr 7, artikel-id 1257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Excavators are one of the most energy-intensive elements of earthwork operations. Predicting the energy consumption and CO2 emissions of excavators is therefore critical in order to mitigate the environmental impact of earthwork operations. However, there is a lack of method for estimating such energy consumption and CO2 emissions, especially during the early planning stages of these activities. This research proposes a model using an artificial neural network (ANN) to predict an excavator's hourly energy consumption and CO2 emissions under different site conditions. The proposed ANN model includes five input parameters: digging depth, cycle time, bucket payload, engine horsepower, and load factor. The Caterpillar handbook's data, that included operational characteristics of twenty-five models of excavators, were used to develop the training and testing sets for the ANN model. The proposed ANN models were also designed to identify which factors from all the input parameters have the greatest impact on energy and emissions, based on partitioning weight analysis. The results showed that the proposed ANN models can provide an accurate estimating tool for the early planning stage to predict the energy consumption and CO2 emissions of excavators. Analyses have revealed that, within all the input parameters, cycle time has the greatest impact on energy consumption and CO2 emissions. The findings from the research enable the control of crucial factors which significantly impact on energy consumption and CO2 emissions.

  • 20.
    Jassim, Hassanean
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Babylon University.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Quantification of Energy Consumption and Carbon Dioxide Emissions During Excavator Operations2018Ingår i: Advanced Computing Strategies for Engineering: 25th EG-ICE International Workshop 2018, Lausanne, Switzerland, June 10-13, 2018, Proceedings, Part I, Cham, 2018, s. 431-453Konferensbidrag (Refereegranskat)
    Abstract [en]

    A number of studies have assessed the energy consumed and carbon dioxide emitted by construction machinery during earthwork operations. However, little attention has been paid to predicting these variables during planning phases of such operations, which could help efforts to identify the best options for minimizing environmental impacts. Excavators are widely used in earthwork operations and consume considerable amounts of fuel, thereby generating large quantities of carbon dioxide. Therefore, rigorous evaluation of the energy consumption and emissions of different excavators during planning stages of project, based on characteristics of the excavators and projects, would facilitate selection of optimal excavators for specific projects, thereby reducing associated environmental impacts. Here we describe use of artificial neural networks (ANNs), developed using data from Caterpillar’s handbook, to model the energy consumption and CO2 emissions of different excavators per unit volume of earth handled. We also report a sensitivity analysis conducted to determine effects of key parameters (utilization rate, digging depth, cycle time, bucket payload, horsepower, load factor, and hauler capacity) on excavators’ energy consumption and CO2 emissions. Our analysis shows that environmental impacts of excavators can be most significantly reduced by improving their utilization rates and/or cycle times, and reducing their engine load factor. We believe our ANN models can potentially improve estimates of energy consumption and CO2 emissions by excavators. Their use in planning stages of earthworks projects could help planners make informed decisions about optimal excavator(s) to use, and contractors to evaluate environmental impacts of their activities. Finally, we describe a case study, based on a road construction project in Sweden, in which we use empirical data on the quantities and nature of the materials to be excavated, to estimate the environmental impact of using different excavators for the project

  • 21.
    Jassim, Hassanean S. H.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    A Practical Method for Assessing the Energy Consumption and CO2 Emissions of Mass Haulers2016Ingår i: Energies, E-ISSN 1996-1073, Vol. 9, nr 10, artikel-id 802Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mass hauling operations play central roles in construction projects. They typically use many haulers that consume large amounts of energy and emit significant quantities of CO2. However, practical methods for estimating the energy consumption and CO2 emissions of such operations during the project planning stage are scarce, while most of the previous methods focus on construction stage or after the construction stages which limited the practical adoption of reduction strategy in the early planning phase. This paper presents a detailed model for estimating the energy consumption and CO2 emissions of mass haulers that integrates the mass hauling plan with a set of predictive equations. The mass hauling plan is generated using a planning program such as DynaRoad in conjunction with data on the productivity of selected haulers and the amount of material to be hauled during cutting, filling, borrowing, and disposal operations. This plan is then used as input for estimating the energy consumption and CO2 emissions of the selected hauling fleet. The proposed model will help planners to assess the energy and environmental performance of mass hauling plans, and to select hauler and fleet configurations that will minimize these quantities. The model was applied in a case study, demonstrating that it can reliably predict energy consumption, CO2 emissions, and hauler productivity as functions of the hauling distance for individual haulers and entire hauling fleets.

  • 22.
    Jassim, Hassanean S.H.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Civil Engineering, College of Engineering, University of Babylon.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Assessing energy consumption and carbon dioxide emissions of off-highway trucks in earthwork operations: an artificial neural network model2018Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 198, s. 364-380Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Methods capable of predicting the energy use and CO2 emissions of off-highway trucks, especially in the initial planning phase, are rare. This study proposed an artificial neural networks (ANN) model to assess such energy use and CO2 emissions for each unit volume of hauled materials associated with each hauling distance. Data from discrete event simulations (DES), an off-highway truck database, and different site conditions were simultaneously analyzed to train and test the proposed ANN model. Six independent quantities (i.e., truck utilization rate, haul distance, loading time, swelling factor, truck capacity, and grade horsepower) were used as the input parameters for each model. The developed model is an efficient tool capable of assessing the energy use and CO2 emissions of off-highway trucks in the initial planning stage. The results revealed that the grade horsepower and haul distances yield a significant increase in the environmental impact of the trucks. In addition, the results demonstrated that, for a given set of project conditions, the environmental impact of trucks can reduced by improving their utilization rate and reducing the loading time.

  • 23.
    Krantz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Larsson, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Assessing Embodied Energy and Greenhouse Gas Emissions in Infrastructure Projects2015Ingår i: Buildings, E-ISSN 2075-5309, Vol. 5, nr 4, s. 1156-1170Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Greenhouse gas (GHG) emissions from construction processes are a serious concern globally. Of the several approaches taken to assess emissions, Life Cycle Assessment (LCA) based methods do not just take into account the construction phase, but consider all phases of the life cycle of the construction. However, many current LCA approaches make general assumptions regarding location and effects, which do not do justice to the inherent dynamics of normal construction projects. This study presents a model to assess the embodied energy and associated GHG emissions, which is specifically adapted to address the dynamics of infrastructure construction projects. The use of the model is demonstrated on the superstructure of a prefabricated bridge. The findings indicate that Building Information Models/Modeling (BIM) and Discrete Event Simulation (DES) can be used to efficiently generate project-specific data, which is needed for estimating the embodied energy and associated GHG emissions in construction settings. This study has implications for the advancement of LCA-based methods (as well as project management) as a way of assessing embodied energy and associated GHG emissions related to construction.

  • 24.
    Krantz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johansson, Tim
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    An Energy Model for Sustainable Decision-Making in Road Construction Projects2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Road construction operations often require considerable amounts of energy in the form of fossil fuels, thus generating considerable greenhouse gas (GHG) emissions. While fuel efficiency of the heavy construction equipment is extensively studied, limited attention is given to how the construction process can be planned in order to reduce energy use and GHG-emissions. In this paper a conceptual model is proposed for the assessment of energy use and GHG-emission in road construction projects. When applied to a case study the conceptual energy model is a useful tool to asses and evaluate project alternatives in the early planning stages of road construction projects. As a result both the energy use and GHG-emissions in road construction projects can be reduced.

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  • 25.
    Krantz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Johansson, Tim
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Analysis of alternative road construction staging approaches to reduce carbon dioxide emissions2017Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 143, s. 980-988Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite many studies focusing on assessing energy use and carbon dioxide emissions in road projects, limited attention has been given to practical methods for mitigating environmental impacts at the project planning stage. Our study addresses this issue by proposing a model incorporating a step-by-step guide for calculating carbon dioxide emissions in the project. This model is practically applied to a road construction project where two major supply chain alternatives are evaluated and compared. The findings suggest that major reductions of carbon dioxide emissions can be achieved by (1) identifying and comparing a set of realistic project alternatives, and (2) conducting this at an early stage of the project planning process so that favorable alternatives can be implemented during construction.

  • 26.
    Krantz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Shadram, Farshid
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Larsson, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    A Model for Assessing Embodied Energy and GHG Emissions in Infrastructure Projects2015Ingår i: ICCREM 2015: Environment and the Sustainable Building : proceedings of the 2015 international conference on construction and real estate management : August 11-12, 2015 Luleå, Sweden / [ed] Yaowu Wang; Thomas Olofsson; Geoffrey Qiping Shen; Yong Bai, Reston, Va: American Society of Civil Engineers (ASCE), 2015, s. 1070-1077Konferensbidrag (Refereegranskat)
    Abstract [en]

    Construction and operation of buildings and infrastructure is a main contributor to emissions of greenhouse gases (GHG) in Sweden. The embodied energy of construction, meaning all the energy that is used until the completion of the construction project (see Figure 1), cause roughly 10 million tones of CO2 equivalent emissions each year which equals to the emissions from all cars in Sweden (IVA 2014). About 6 million tones of CO2 equivalent emissions are attributed to the embodied energy of roads, railroads and other civil works while the remaining 4 million tones are attributed to the embodied energy of buildings (IVA 2014). Although reducing energy use and associated GHG-emissions in road and railroad construction is prioritized by the Swedish Transport Administration (Trafikverket 2012), the GHG-emissions from such construction projects have increased in recent years (Boverket 2014). Many of the existing efforts to reduce energy use and associated GHG-emissions focus on individual phases of the life cycle and don’t take into consideration the effects at other stages during the whole life cycle of a project (Boverket 2011). A crucial step in the assessment of energy use and associated GHG-emissions is to clarify and categorize the different phases of a life cycle. Figure 1 shows a proposed categorization of life cycles phases and use of energy based on previous research (Davies et al. 2014). Buildings’ main use of energy happens during its operational phase from e.g. heating, lighting and use of electrical appliances (Sartori and Hestnes 2007). In infrastructure projects such as road construction the embodied energy is roughly equal to the operational energy for roads with lighting, or in fact considerably higher if the road lacks lighting (Stripple 2001).

  • 27.
    Larsson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Krantz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Discrete Event Simulation Analysis of Product and Process Platforms: A Bridge Construction Case Study2016Ingår i: Journal of construction engineering and management, ISSN 0733-9364, E-ISSN 1943-7862, Vol. 142, nr 4, artikel-id 4015097Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Product and process platforms have been promoted as possible enablers of increased productivity in civil engineering. However, such platforms are traditionally applied in mass manufacturing industries where production assets are employed in continuous production of uniform products, which strongly facilitates continuous improvement. The discontinuous nature of project-based production in civil engineering restricts such possibilities. Thus, if platforms are implemented there is a need for methods capable of evaluating the performance of integrated product and production process configurations in specific projects. A possibility, explored in this paper, is to use database-driven simulation. As a case study, a configurable simulation model, based on standardized process patterns and values stored in a platform, has been developed of the production for a bridge concept. The presented results provide evidence that database-driven simulation can support efficient platform evaluation and development by integrating product and process information, even in discontinuous, project-based industrial sectors. The results specifically demonstrate that this approach can be used to evaluate effects of different configurations of construction methods on working time requirements without time-consuming updates of models.

  • 28.
    Larsson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Platform concepts in bridge construction2014Ingår i: Computing in civil and building engineering: proceedings of the 2014 International Conference on Computing in Civil and Building Engineering : June 23-25, 2014, Orlando, Florida / [ed] Raymond Issa; Ian Flood, Reston, VA: American Society of Civil Engineers (ASCE), 2014, s. 1473-1480Konferensbidrag (Refereegranskat)
    Abstract [en]

    Improving productivity and innovation is a central challenge in all industries, but particularly in construction where improvements have been slow. The Swedish Transportation Administration, the largest public client in Sweden, has launched a research and innovation program to increase productivity by foster an industrial approach and identify ways to increase the standardization of products and processes. The use of customizable platforms in bridge construction is in this paper explored as a tool for increasing the standardization. Especially the connection between the product and process platforms is exemplified using a developed bridge concept by a Swedish contractor. The development of modular platforms needs to consider which components and processes that can be specified (standardized) in advance and which that needs to be uniquely adapted to the specific project. Also, the encapsulation of knowledge in standardized design and construction modules in supporting platforms and configuration tools turn tacit personal know-how into formal explicit knowledge that can be managed and continuously improved by the construction company.

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  • 29.
    Lu, Weizhuo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Erikshammar, Jarkko
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Integrating design and production: A component-oriented framework for industrialized housing2011Ingår i: Proceedings of the 2011 eg-ice Workshop / [ed] Timo Hartmann; Pieter de Wilde; Yaqub Rafiq, Twente: University of Twente , 2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This research proposes a component-oriented framework integrating design and production, which enables customer and designer together to customize housing design and avoid ad-hoc design in order to industrialize and standardize housing production. The component-oriented framework facilitates the reuse of components, quickly configures and assesses of alternative housing designs. The developed visualization-simulation modelling provides a consistent and transparent communication platform for customers, designers and builders, where components flow intelligently according to specific sequences, resource requirements, order numbers and durations. A case study of industrialized doors production is used to illustrate proposed component-oriented framework.

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  • 30.
    Lu, Weizhuo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Feng, Kailun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Department of Construction Management, Harbin Institute of Technology, Harbin 150009, China; Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, Harbin 150090, China; Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology, Harbin Institute of Technology, Harbin 150090, China.
    Big-data driven building retrofitting: An integrated Support Vector Machines and Fuzzy C-means clustering method2020Ingår i: WSBE 20 - World Sustainable Built Environment - Beyond2020 2-4 November 2020, Gothenburg, Sweden / [ed] Holger Wallbaum; Alexander Hollberg; Liane Thuvander; Paula Femenias; Izabela Kurkowska; Kristina Mjörnell; Colin Fudge, Institute of Physics (IOP), 2020, artikel-id 042013Konferensbidrag (Refereegranskat)
    Abstract [en]

    It has become a mainstream to use physical models to quantify expected energy savings from alternative retrofit methods and technologies. However, they are not suitable for predicting energy use of buildings when detailed and specified input parameters are unavailable. The overall purpose of the research is to support the stakeholders in taking decisions on refurbishments options when not all of physical information is available, in order to achieve the Swedish Energy Agency's measurements of near-zero energy buildings. The research will transfer big data from Swedish Energy Performance Certificates for building retrofitting. A Support Vector Machines and Fuzzy C-means clustering (SVM-FCM) integrated machine learning algorithm is used directly to extract the case-specific knowledge from EPC big data regarding building characteristics and energy saving of retrofit measures. It enables to prioritize retrofit measures and compute their expected energy savings for buildings. This proposed data driven method is an attempt of taking advantage of big data for practical building retrofit selection.

  • 31. Lu, Weizhuo
    et al.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    A continuous flow simulation model for probability repetitive projects2009Ingår i: Proceedings of 5th Nordic Conference on Construction Economics and Organisation: Reykjavík University, Iceland 10-12 June 2009, Reykjavik: University of Reykjavik , 2009, Vol. 1Konferensbidrag (Refereegranskat)
    Abstract [en]

    Continuous flow is one of the main focuses of scheduling repetitive projects. Construction practitioners and researchers have proposed approaches to maintain continuous flows. However, many of these approaches only consider deterministic activity durations or have some other methodological limitations. Accordingly, a continuous flow simulation model is presented in this paper in order to overcome aforementioned limitations. The proposed model integrates simulation and buffering to consider the probability of activities durations and for proper sizing of buffers. Instead of having the same activity duration distribution on different units as is common, the proposed model allows for different activity duration distribution between units. The proposed model is tested and validated on a case study and the results show that the model can provide practical contributions in scheduling that effectively maintain continuous flow for probability repetitive project. Possible further research directions in this regard are also discussed in the paper.

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  • 32.
    Lu, Weizhuo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Building information modeling and discrete event simulation: towards an integrated framework2014Ingår i: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 44, s. 73-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of a realistic Discrete Event Simulation (DES) model needs the complete specification of the interdependencies between activities and resources. Also, the maintenance of an existing DES model is challenging especially when changes in the logical relationships between activities, resource allocation and design need to be considered. The process of development and maintenance is time-consuming, error-prone and it restricts the application of DES within the construction industry. In this research, a Building Information Modeling (BIM) and DES framework is proposed to enable the implementation and integration of DES in the planning and follow-up of construction activities. The framework consists of: (1) A building information modeling process that exports material quantity take-offs, schedules and required resources to a relational database and (2) An intelligent simulation engine that automatically reads information from the database at the start of each simulation run. This implies that changes in the building information modeling process, such as design modification, different resource allocations and alternative construction methods can be explored without manually checking and re-formalizing the simulation model. A preliminary prototype has been developed using the proposed BIM-DES framework. The initial results show that the proposed BIM-DES framework reinforces both elements by providing valuable additional information. BIM provides the product and process information to DES, facilitating the building and maintenance of the DES model; the DES model evaluates the construction performances and provides valuable feedback to the BIM process for decision support.

  • 33.
    Lu, Weizhuo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Jensen, Patrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Simonsson, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    BIM-based lean-agile supply chain for industrialized housing2011Ingår i: CONVR 2011: Proceedings of the 11th International Conference on Construction Applications of Virtual Reality / [ed] Hans-Joachim Bargstädt; Karin Ailland, Bauhaus-Universität Weimar , 2011, s. 262-270Konferensbidrag (Refereegranskat)
    Abstract [en]

    From 1990 to 2002, approximately 74% single-family detached houses in Sweden are prefabricated by industrialized housing builders. To fulfill the benefits of industrialization, the design specifications have to be worked out from a list of predefined standardized components and elements. On the other hand, the requirements of client (diversity, cost and delivery time) make design specification process seems to be complex and paradoxical situation, which may lead to the ad-hoc design customization and slow response to potential client’s enquiry. This research therefore presents a BIM-based configuration design, in which lean-agile supply chain is used to balance and manage the trade-off between builders and clients, standardization and customization. Furthermore, integrating discrete event simulation (DES) with building information model (BIM) enables an enriched information model including cost and delivery time. The research argues that the industrialized housing is the systematic trade-off and balancing the values of all stakeholders and BIM-based lean-agile industrialized configuration design provides an effective trade-off platform.

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  • 34.
    Lu, Weizhuo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Segerstedt, Anders
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Application of discrete event simulation and CONWIP on inventory control2010Ingår i: Proceedings of the CIB W78 2010: 27th International Conference - Cairo, Egypt, 16-18 November, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Simulation is an effective quantitative analysis tool to compare and evaluate different system design. However, the application of simulation in construction industry has been limited to relatively restricted research fields. This paper presents a discrete event simulation (DES) model using Simphony.net in which quantitative performance evaluation between constant work-in-progress (CONWIP), a pull method that limits the work-in-progress (WIP) level in the production system according to the status of system, and push are provided. A card element in the simulation model is used to authorize the production, collect cards and limit work-in-progress (WIP) level in the system. The purpose of such comparison and evaluation is to explore the utilization of DES and CONWIP on inventory control.Uncertainty and variation in construction process has an important influence on project performance. The common practice to deal with variation is the holding of inventory. As demonstrated in developed simulation model in this research, suitable inventory improves the performance of project. However, excessive inventory induces no-added value. Simulation experiments show that application of DES and CONWIP provides an effective way of inventory control, simultaneously, maintain throughput and cycle time compared to push system. The research will be of interest to those evaluating the impacting of lean base method on construction project performance with simulation.Keywords: DES, inventory control, lean, CONWIP

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  • 35. Lu, Weizhuo
    et al.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    A lean-agile model of homebuilders' production systems2011Ingår i: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 29, nr 1, s. 25-35Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A lean-agile model of homebuilders' production systems is proposed in this research. Value stream mapping is utilized to clarify the proposed lean-agile model, in which pull and Kanban are used to ensure smooth production upstream of the de-coupling point, while fluctuating market demands in terms of variety of homes and variability of volumes are managed by the agile process downstream of the de-coupling point. The decoupling point is used to provide components to downstream agile process and shield upstream smooth production from market fluctuations. A simulation model is developed to evaluate and validate the effectiveness of the proposed lean-agile model. Simulation experiments show that the lean-agile model prevents the accumulation of high inventory levels and thus provides better customization opportunities for clients compared to even-flow-construction. It also provides a more stable process with shorter cycle times compared to sales-driven production. The proposed lean-agile model offers new possibilities for homebuilders to manage the balance between meeting fluctuating market demands and stabilizing the production system.Keywords: Agile, housing construction, lean, simulation.

  • 36.
    Man, Quingpeng
    et al.
    School of Management. Harbin Institute of Technology.
    Sun, Chengshuang
    School of Management. Harbin Institute of Technology.
    Fei, Yuesheng
    YueshengFei, Industrial Securities Co.,Ltd.
    Skitmore, Martin
    School of Civil Engineering and Built Environment, Queensland University of Technology.
    Bai, Yong
    Department of Construction Management and Engineering, North Dakota State University, Fargo, ND.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Government motivation-embedded return guarantee for urban infrastructure projects based on real options2016Ingår i: Journal of Civil Engineering and Management, ISSN 1392-3730, E-ISSN 1822-3605, Vol. 22, nr 7, s. 954-966Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Governments usually guarantee the amount of investment income to private sector partners to encourage their participation in Public-Private Partnership urban infrastructure development projects, with the ‘float return on investment guarantee’ being the main method in use by the Chinese government today. The current problems with the float return on investment guarantee are analysed and a guarantee approach with embedded motivatio nal behaviour is presented as an alternative. A pricing method option is then introduced as the motivation-embedded return guarantee has similar characteristics to real options. From this, a valuation model is developed that provides the basis of a new systematic method for calculating the government guarantee value

  • 37.
    Olofsson, Thomas
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Jensen, Patrik
    Design Evolution.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Larsson, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Product and Process Platforms in Transport Infrastructure Projects2016Ingår i: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, s. 529-536Konferensbidrag (Refereegranskat)
    Abstract [en]

    Construction is traditionally a trade that produces unique, one-off products designed specifically according to the project requirements. However, recently developed flexible product and process platforms in industrialized house building based on the theory of mass customisation offer products that can be customized to a large extent with affordable costs. In this paper we present a framework for how a product and process platform can be developed and used in a traditional engineer-to-order design and construction of transport infrastructure products. The framework is exemplified in a case study, where a typical concrete bridge type is modularised and customized using a product configurator.  A database driven simulation model using process patterns and values stored in the platform, is then constructed to test the buildability of the bridge configuration. The results presented provide evidence that product and process platforms can support the design, and planning process of transport infrastructure projects, by integrating product and process information. The results specifically demonstrate how product configuration and database-driven simulation can be used to evaluate the effects of design alternatives and construction methods on performance measures such as productivity and environmental impact.

  • 38.
    Sandberg, Marcus
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Gerth, Robert
    Design Evolution Scandinavia AB.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Jansson, Gustav
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Mukkavaara, Jani
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Design automation in construction: An overview2016Ingår i: Proceedings of the 33rd CIB W78 Conference 2016, Oct. 31st – Nov. 2nd 2016, Brisbane, Australia, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    As the construction industry continues its digital journey the applications within design automation is growing, making development processes less time-demanding and more organized. Design automation applications can show design impact on e.g. cost, equipment availability, staff capabilities and buildability. It can also facilitate reuse of successful solutions instead of reinventing the wheel for every project. Thanks to automation it becomes easier to generate several solutions and trying different what-if-conditions. The field has many different approaches but an overview for construction where the connections between the different approaches are indicated is needed. The purpose of this paper is to describe our view of how the design automation fields of building information modelling, master models,  nowledge-based engineering, configuration, modularization, platforms and simulation are  onnected and to provide input to the design automation discussion in construction. Each of  hese areas are introduced and then they are analyzed in relation to each other and presented as an overview. These results will serve as a base for future studies.

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  • 39.
    Segerstedt, Anders
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Pettersen, Jan-Arne
    Industriell teknologi, Norges Arktiske Universitet, Narvik, Norway.
    Holmbom, Martin
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi. Gestamp Hardtech AB, Luleå, Sweden.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Zhang, Qinhong
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi. Sino-US Global Logistics Institute, Shanghai Jiao Tong University, P. China.
    Order quantities in a production line: influences on production output and lead-time2020Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    This article tests the effect of different order quantities and setup times and its dependence of maximum Work-in-Process (WIP). The main studied supply chain consists of five linked machines with a fixed setup time for every batch in every machine, and stochastic operation times for every item in the batch. Additionally three linked machines with a clear bottleneck are studied. Production management can only control maximum WIP and not average WIP. Average WIP is a consequence of released work, variations, capacity and maximum WIP. A number of test cases are made where the number of units in the machines and the buffer areas are restricted. Previous studies have shown the dominance of CONWIP over Kanban, so only situations where maximum WIP is restricted in the total production line is studied. – The results show that increased maximum WIP leads to longer average lead-time but also that its coefficient of variation increases, independent of setup time and order quantity. A literature review confirms our assumption and opinion that large variations in lead-times are worse than long lead-times. A smaller order quantity leads to a lower production rate if not the setup time is decreased proportionally. A reduction of the order quantity can also increase the lead-time and its variation. A decrease of the order quantity requires a reduction of maximum WIP to implement its advantages. Therefore, reducing order quantities but still use the same parameters in in the companies’ computer system for material- and production control will prevent improvements. It is always favourable to reduce setup times and/or variation in operation times.

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  • 40.
    Shadram, Farshid
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johansson, Tim
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    An Integrated BIM-based framework for energy assessment of the building upstream flow2015Ingår i: ICCREM 2015: Environment and the Sustainable Building : proceedings of the 2015 international conference on construction and real estate management : August 11-12, 2015 Luleå, Sweden / [ed] Yaowu Wang; Thomas Olofsson; Geoffrey Qiping Shen; Yong Bai, Reston, Va: American Society of Civil Engineers (ASCE), 2015, s. 107-118Konferensbidrag (Refereegranskat)
    Abstract [en]

    The construction and operation of buildings account for a significant part of the energy use and greenhouse gas emissions. Most design approaches to reduce the use of energy are focusing on the operational phase of a building’s life. Consequently, the embodied energy from the upstream flow, including production of building material and components, transport and assembly on-site, is often disregarded in the development of energy-efficient buildings. The purpose of this research is to propose a method to facilitate the assessment of the embodied energy and carbon footprint during the design and planning stage from the production of building material and components including the transportation to site. The framework makes use of Environmental Product Declaration (EPD) and supply chain information stored in a relational database of building materials and components, Building Information Models (BIM) for the assessment of the embedded energy in the building. Further, the feature manipulation engine (FME) is used to track transportation distances and transportation times from Google Map (GM) for the assessment of embedded energy from supplier to the construction site. Finally, a prototype is developed to demonstrate the practical application of the framework and to observe possible limitations and barriers.

  • 41.
    Shadram, Farshid
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Johansson, Tim
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Schade, Jutta
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    An integrated BIM-based framework for minimizing embodied energy during building design2016Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 128, s. 592-604Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Assessment of the embodied energy associated with the production and transportation of materials during the design phase of building provides great potential to profoundly affect the building’s energy use and sustainability performance. While Building Information Modeling (BIM) gives opportunities to incorporate sustainability performance indicators in the building design process, it lacks interoperability with the conventional Life Cycle Assessment (LCA) tools used to analyse the environmental footprints of materials in building design. Additionally, many LCA tools use databases based on industry-average values and thus cannot account for differences in the embodied impacts of specific materials from individual suppliers. To address these issues, this paper presents a framework that supports design decisions and enables assessment of the embodied energy associated with building materials supply chain based on suppliers’ Environmental Product Declarations (EPDs). The framework also integrates Extract Transform Load (ETL) technology into the BIM to ensure BIM-LCA interoperability, enabling an automated or semi-automated assessment process. The applicability of the framework is tested by developing a prototype and using it in a case study, which shows that a building’s energy use and carbon footprint can be significantly reduced during the design phase by accounting the impact of individual material in the supply chain.

  • 42.
    Shadram, Farshid
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Assessment of the Energy Use and CO2 Emissions from a Construction Site: An Integrated BIM-DES-LCA Framework2017Ingår i: ICCREM 2016: BIM Application and Offsite Construction - Proceedings of the 2016 International Conference on Construction and Real Estate Management 2016 / [ed] Wang Y.,Al-Hussein M.,Shen G.Q.P.,Zhu Y., Reston, VA: American Society of Civil Engineers (ASCE), 2017, s. 518-526Konferensbidrag (Refereegranskat)
    Abstract [en]

    The building sector contributes significantly to the energy use and related greenhouse gas (GHG) emissions. Prior research has mainly focused on the impacts associated with material selection and building operation, thereby the embodied impact of the construction phase has got limited attention. The construction phase usually suffers from an inherent uncertainty in which construction operations, activities, and resources interact with each other in a complex manner. The discrete event simulation (DES) has been recognized to be a consistent simulation approach to capture these uncertainties and interactions. DES can also complement conventional life cycle assessment (LCA) tools, used for sustainable design and environmental strategies. However, the major challenge has been the implementation of the DES into practice which needs significant effort and work in order to create a realistic model of the construction process. To overcome this obstacle, this paper proposes a framework that integrates building information modeling (BIM), DES, and LCA in order to support the environmental evaluation and also facilitate implementation of the DES model by utilizing the data-rich BIM. Finally, the practical application of the proposed BIM-DES-LCA framework is demonstrated in a preliminary prototype and the areas where further development is required have been highlighted to address in future research

  • 43.
    Wallström, Peter
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    The Interaction of Contractor’s Cost Flow with Operational Practice: A Simulation Study2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The construction companies are struggling for cost control in construction projects. This is often based on cost estimation of scheduled activities. A project may fail due to lack of cash even if it is profitable. The cash flow presents dynamic characteristic which is changing with time progress and it is influenced by the uncertainty project environment, such as supply chain variation, equipment failure and the deviation of working efficiency.At the same time, the increasing market competition forces these companies to transfer from the traditional practice to more advanced and efficient practices, such as lean or flexible production. However, to use lean or flexible production might not prove successful unless the practices are introduced in the right environment. The resources are used in a very efficient way concerning lean, but the practice demand a high degree of predictability. The opposite is true for a flexible production. The resources are not used as efficient but can then on the other hand handle variation better than lean. The research is based on the question: How does managerial operational practices and variation in production influence the cash flow? A model is proposed to simulate and forecast the cash flow considering the uncertainty project environment and selected operational practice. A case study including six scenarios (high and low variation, three operation practices) is used to illustrate the proposed model. A conclusion is that it is important to consider both managerial aspects as well as operational aspects in order to avoid sub-optimization in production. From the cash flow management perspective, the proposed model can assist the contractor to forecast the cash flow and synchronize the operational practices with project environment

  • 44.
    Wang, Yaowu
    et al.
    Department of Construction Management, Harbin Institute of Techn.
    Feng, Kailun
    Department of Construction Management, Harbin Institute of Technology.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    An environmental assessment and optimization method for contractors2016Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 142, nr 4, s. 1877-1891Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction-related environmental impacts have increased with the rapid urbanization in China. Contractors could mitigate the environmental impacts of a building's construction phase by developing an environmentally-friendly construction scheme. However, a construction scheme that performs well on one environmental metric may perform poorly on others. Moreover, it becomes challenging to select the best plan when various construction schemes and diverse environmental metrics need to be considered.

    This research explores how a multi-objective optimization method can provide Pareto optimal solutions that will help the contractor select a construction scheme that performs well on all environmental metrics. A quantitative environmental assessment and optimization method (EAOM) was established to evaluate and optimize the construction environmental performance using a combination of Life Cycle Assessment (LCA) and Particle Swarm Optimization (PSO). Assessment and optimization were implemented as two integrated and interactively functional modules to complement LCA in multi-objective decision support. In a case of reinforced concrete project, EAOM generated four Pareto construction schemes within 864 possible solutions in a remarkably short time. The results indicate that EAOM is an effective and efficient decision support tool that contractors can implement to improve the environmental performance of construction processes. 

  • 45.
    Yang, Bin
    et al.
    School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Wang, Faming
    Institute of Textiles and Clothing, The Hong Kong Polytechnic University.
    Lu, Weizhuo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Thermal comfort in primary school classrooms: A case study under subarctic climate area of Sweden2018Ingår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 135, s. 237-245Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Limited studies were focused on primary school buildings especially under subarctic climate. Thermal comfort of children was assumed to be similar as that of adults, which may cause inaccuracy. To fill data blank and enrich global database, a field study was performed from late fall 2016 to early spring 2017 covering whole heating period in north part of Sweden. Indoor CO2 concentration was continuously monitored to evaluate indoor ventilation. Thermal comfort related parameters were continuously measured and predicted mean vote (PMV) was calculated. Subjective questionnaire surveys were performed every week except holidays. Subjective thermal sensation value (TSV) was always higher than objective PMV, which reflected thermal adaptation. The thermal adaptation became not obvious in middle and late winter because of long term exposure to heating environments. Heating system should be intensified gradually in early heating period, operated based on actual outdoor climate instead of experience in middle and late heating periods, extended under part load operation in early spring if necessary. The new 13─point TSV scale was pointed out by other researchers and tested inthis study, which can explore tiny TSV deviations from thermally neutral status and reflect more accurate thermal sensations.

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