Change search
Refine search result
1 - 38 of 38
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Chen, Shiwei
    et al.
    Feng, Kailun
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    A Simulation-Based Optimisation for Contractors in Precast Concrete Projects2019Conference paper (Refereed)
    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.

  • 2.
    Erikshammar, Jarkko
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Alestig, Erik
    Prolog AB.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Parametric Value Stream Mapping Framework: A Case Study of a Small Swedish Industrialized House-Building Supplier2014In: 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, p. 425-436Conference paper (Refereed)
    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.

  • 3.
    Erikshammar, Jarkko
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Discrete event simulation enhanced value stream mapping: an industrialized construction case study2013In: Lean Construction Journal, ISSN 1555-1369, E-ISSN 1555-1369, Vol. 10, p. 47-65Article in journal (Refereed)
    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 manufacturerFindings: 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.

  • 4.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Machine learning based construction simulation and optimization2018In: Proceedings of the 2018 Winter Simulation Conference / [ed] M. Rabe; A.A. Juan; N. Mustafee; A. Skoogh; S. Jain; B. Johansson, IEEE, 2018, p. 2025-2036, article id 8632290Conference paper (Refereed)
    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.

  • 5.
    Feng, Kailun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Chen, Shiwei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. 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 Warming2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 11, article id 4207Article in journal (Refereed)
    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.

  • 6.
    Feng, Kailun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Department of Construction Management, Harbin Institute of Technology, Harbin, 150001, China.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Chen, Shiwei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. 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 study2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 11, article id 3868Article in journal (Refereed)
    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.

  • 7.
    Feng, Kailun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Department of Construction Management, Harbin Institute of Technology, Harbin, China.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    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 method2019In: Sustainable cities and society, ISSN 2210-6707, Vol. 50, article id 101596Article in journal (Refereed)
    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.

  • 8.
    Feng, Kailun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Department of Construction Management, Harbin Institute of Technology.
    Wang, Yaowu
    Department of Construction Management, Harbin Institute of Techn.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    The Environmental Performance of Prefabricated Building and Construction: A Critical Review2017In: 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, p. 18-42Conference paper (Refereed)
    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

  • 9.
    Feng, Kailun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Wang, Yaowu
    Harbin Institute of Technology.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Li, Xiaodong
    Department of Construction Management, Harbin Institute of Technology.
    Weakness of Embodied Energy Assessment on Construction: A Literature Review2016In: 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, p. 547-559Conference paper (Refereed)
    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

  • 10.
    Haller, Martin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jansson, Gustav
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    An indicator for superfluous iteration in offsite building design processes2015In: Architectural Engineering and Design Management, ISSN 1745-2007, E-ISSN 1752-7589, Vol. 11, no 5, p. 360-375Article in journal (Refereed)
    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.

  • 11.
    Jassim, Hassanean
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Krantz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    A Cradle-to-Gate Framework for Optimizing Material Production in Road Construction2016In: 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, no 19, p. 758-764Conference paper (Refereed)
    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.

  • 12.
    Jassim, Hassanean
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Krantz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Luleå University of Technology.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    A Model to Reduce Earthmoving Impacts2019Article in journal (Refereed)
  • 13.
    Jassim, Hassanean
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Determining the environmental impact of material hauling with wheel loaders during earthmoving operations2019In: Journal of the Air and Waste Management Association, ISSN 1096-2247, E-ISSN 2162-2906, Vol. 69, no 10, p. 1195-1214Article in journal (Refereed)
    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.

  • 14.
    Jassim, Hassanean
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Predicting energy consumption and CO2 emissions of excavators in earthwork operations: An artificial neural network model2017In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 9, no 7, article id 1257Article in journal (Refereed)
    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.

  • 15.
    Jassim, Hassanean
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Babylon University.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Quantification of Energy Consumption and Carbon Dioxide Emissions During Excavator Operations2018In: Advanced Computing Strategies for Engineering: 25th EG-ICE International Workshop 2018, Lausanne, Switzerland, June 10-13, 2018, Proceedings, Part I, Cham, 2018, p. 431-453Conference paper (Refereed)
    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

  • 16.
    Jassim, Hassanean S. H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    A Practical Method for Assessing the Energy Consumption and CO2 Emissions of Mass Haulers2016In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 9, no 10, article id 802Article in journal (Refereed)
    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.

  • 17.
    Jassim, Hassanean S.H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction. Department of Civil Engineering, College of Engineering, University of Babylon.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Assessing energy consumption and carbon dioxide emissions of off-highway trucks in earthwork operations: an artificial neural network model2018In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 198, p. 364-380Article in journal (Refereed)
    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.

  • 18.
    Krantz, Jan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Larsson, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Assessing Embodied Energy and Greenhouse Gas Emissions in Infrastructure Projects2015In: Buildings, ISSN 2075-5309, E-ISSN 2075-5309, Vol. 5, no 4, p. 1156-1170Article in journal (Refereed)
    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.

  • 19.
    Krantz, Jan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Johansson, Tim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    An Energy Model for Sustainable Decision-Making in Road Construction Projects2014Conference paper (Refereed)
    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.

  • 20.
    Krantz, Jan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Johansson, Tim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Analysis of alternative road construction staging approaches to reduce carbon dioxide emissions2017In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 143, p. 980-988Article in journal (Refereed)
    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.

  • 21.
    Krantz, Jan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Shadram, Farshid
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Larsson, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    A Model for Assessing Embodied Energy and GHG Emissions in Infrastructure Projects2015In: 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, p. 1070-1077Conference paper (Refereed)
    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).

  • 22.
    Larsson, Johan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Krantz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Discrete Event Simulation Analysis of Product and Process Platforms: A Bridge Construction Case Study2016In: Journal of construction engineering and management, ISSN 0733-9364, E-ISSN 1943-7862, Vol. 142, no 4, article id 4015097Article in journal (Refereed)
    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.

  • 23.
    Larsson, Johan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Platform concepts in bridge construction2014In: 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, p. 1473-1480Conference paper (Refereed)
    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.

  • 24.
    Lu, Weizhuo
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Erikshammar, Jarkko
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Integrating design and production: A component-oriented framework for industrialized housing2011In: Proceedings of the 2011 eg-ice Workshop / [ed] Timo Hartmann; Pieter de Wilde; Yaqub Rafiq, Twente: University of Twente , 2011Conference paper (Other academic)
    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.

  • 25. Lu, Weizhuo
    et al.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    A continuous flow simulation model for probability repetitive projects2009In: Proceedings of 5th Nordic Conference on Construction Economics and Organisation: Reykjavík University, Iceland 10-12 June 2009, Reykjavik: University of Reykjavik , 2009, Vol. 1Conference paper (Refereed)
    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.

  • 26.
    Lu, Weizhuo
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Building information modeling and discrete event simulation: towards an integrated framework2014In: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 44, p. 73-83Article in journal (Refereed)
    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.

  • 27.
    Lu, Weizhuo
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jensen, Patrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Simonsson, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    BIM-based lean-agile supply chain for industrialized housing2011In: CONVR 2011: Proceedings of the 11th International Conference on Construction Applications of Virtual Reality / [ed] Hans-Joachim Bargstädt; Karin Ailland, Bauhaus-Universität Weimar , 2011, p. 262-270Conference paper (Refereed)
    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.

  • 28.
    Lu, Weizhuo
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Segerstedt, Anders
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Application of discrete event simulation and CONWIP on inventory control2010In: Proceedings of the CIB W78 2010: 27th International Conference - Cairo, Egypt, 16-18 November, 2010Conference paper (Refereed)
    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

  • 29. Lu, Weizhuo
    et al.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    A lean-agile model of homebuilders' production systems2011In: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 29, no 1, p. 25-35Article in journal (Refereed)
    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.

  • 30.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Government motivation-embedded return guarantee for urban infrastructure projects based on real options2016In: Journal of Civil Engineering and Management, ISSN 1392-3730, E-ISSN 1822-3605, Vol. 22, no 7, p. 954-966Article in journal (Refereed)
    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

  • 31.
    Olofsson, Thomas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Jensen, Patrik
    Design Evolution.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Larsson, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Product and Process Platforms in Transport Infrastructure Projects2016In: 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, p. 529-536Conference paper (Refereed)
    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.

  • 32.
    Sandberg, Marcus
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Gerth, Robert
    Design Evolution Scandinavia AB.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Jansson, Gustav
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Mukkavaara, Jani
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Design automation in construction: An overview2016In: Proceedings of the 33rd CIB W78 Conference 2016, Oct. 31st – Nov. 2nd 2016, Brisbane, Australia, 2016Conference paper (Refereed)
    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.

  • 33.
    Shadram, Farshid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Johansson, Tim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    An Integrated BIM-based framework for energy assessment of the building upstream flow2015In: 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, p. 107-118Conference paper (Refereed)
    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.

  • 34.
    Shadram, Farshid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Johansson, Tim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Schade, Jutta
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    An integrated BIM-based framework for minimizing embodied energy during building design2016In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 128, p. 592-604Article in journal (Refereed)
    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.

  • 35.
    Shadram, Farshid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Assessment of the Energy Use and CO2 Emissions from a Construction Site: An Integrated BIM-DES-LCA Framework2017In: 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, p. 518-526Conference paper (Refereed)
    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

  • 36.
    Wallström, Peter
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    The Interaction of Contractor’s Cost Flow with Operational Practice: A Simulation Study2013Conference paper (Refereed)
    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

  • 37.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    An environmental assessment and optimization method for contractors2016In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 142, no 4, p. 1877-1891Article in journal (Refereed)
    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. 

  • 38.
    Yang, Bin
    et al.
    School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Wang, Faming
    Institute of Textiles and Clothing, The Hong Kong Polytechnic University.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Thermal comfort in primary school classrooms: A case study under subarctic climate area of Sweden2018In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 135, p. 237-245Article in journal (Refereed)
    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.

1 - 38 of 38
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf