Modular and Offsite Construction (MOC) Summit Proceedings
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Design Breakdown in Industrialized Construction: Supporting Lean Manufacturing
Get PDFA turn-key commitment towards the client compels the contractor to optimize the entire supply chain from design to delivery of the finished building. Industrialization of residential construction can be accomplished using either an open or a closed platform. In the case of an open platform, the client can greatly affect design solutions and the subsequent production phase. The aim of this research is to explain how design process breakdown into activities and deliveries supports Lean manufacturing in an open platform situation. The most successful industrialized contractor in Sweden was studied through mapping their design process of modular buildings using their visual planning display. Describing the improvement strategy, the visual content, and the standardization efforts in design revealed the support for Lean manufacturing. Analyzing each activity for repetitive elements identified the base for standardization. The conclusion is that design breakdown is a successful method that effectively supports Lean manufacturing and provides a base for standardization in an open platform context
An Application of Fuzzy Ergonomic Assessment for Human Motion Analysis in Modular Construction
Get PDFWork-related Musculoskeletal Disorders (WMSDs) account for about 34% of non-fatal injuries resulting in days away from work in the construction industry. Particularly in modular construction, due to the repetitive nature of the manual tasks, workers are highly exposed to ergonomic risks. To identify workers’ awkward postures that potentially lead to WMSDs, ergonomic assessment tools have been developed and widely used by ergonomists and Occupational Health and Safety (OHS) practitioners. However, the accuracy of these methods is highly affected by the subjectiveness towards the user’s inputs (e.g., body joint angles), which are difficult to accurately determine in given observation time. Consequently, the imprecise estimates of worker postures may result in inaccurate final results and risk intervention plans. In an effort to address this issue, this study applies fuzzy logic techniques to ergonomic evaluation tools—e.g., Rapid Upper Limb Assessment (RULA). By modelling the range of input values using fuzzy sets rather than discrete boundaries, the imprecision inherit in the inputs has less impact on the final RULA score. As a result, an automated fuzzy expert system has been developed by using membership functions and rules created based on the existing RULA method. An experiment is carried out in order to study the amount of imprecision in joint angle values from human estimations while observing a posture, and also to compare the sensitivity of RULA and the developed fuzzy RULA system to input imprecision. The results reveal that although the fuzzy RULA model has high correlation with RULA, it is more accurate and less sensitive to the variance in input values. The developed model presents a methodology to improve the accuracy of ergonomic assessment methods and handle the uncertainty inherent in ergonomic evaluation, providing the construction industry practitioners with an automated technique to evaluate the ergonomic safety of workers
An Analytical Investigation of Modular Concrete-filled Square Steel Tubes based on the Strain Compatibility
Get PDFConcrete-filled square steel tubes demonstrating good structural resistance against vertical and lateral loads can be used for modular constructions. To promote the applications of the composite tubes to modular construction, it is important to provide simple but accurate analytical methods that can elucidate the structural behaviour of the composite tubes. A number of international design codes are known to calculate the flexural load bearing capacity of the concrete-filled square steel tubes. Some, however, are not predicting the behaviour of the composite tubes accurately. An analytical investigation of concrete-filled square steel tubes was presented in this paper. A strain compatibility based design method considering confinement effect of concrete in tubes was proposed to estimate the flexural strength of composite steel tube filled with concrete. Nominal moment capacities estimated in accordance with the standards of AIJ(Japan), AISC(USA), Eurocode4(Europe) and KSSC(Korea) were compared with the analytical value obtained using the strain compatibility based design method. Since the design method with strain compatibility proposed in the study reflects the concrete confinement with accurate estimation of the neutral axis of composite tube section, the flexural moment capacity of composite tube section can be accurately obtained. The test results of other researchers including Lu and Kennedy were used to verify the reliability of the proposed design method. These experimental results were shown to be the best correlated with the analytical results provided by the proposed method in this paper than any other analytical methods proposed by the international codes that were used to calculate flexural load bearing capacity. The 6% of errors were demonstrated by the proposed approach while bigger errors were observed in the analytical calculations of other design codes as large as 17%
Energy Performance Monitoring and Analysis of NetZero Energy Homes (NZEHs)
Get PDFResidential building operations consume a considerable amount of energy, especially in coldclimate regions. The National Energy Board of Canada (NEB) analyzed energy consumption in 2011, and found that energy use in the residential sector, including space heating/cooling, hot water heating, lighting, appliances, and other energy-using devices, accounts for 14% of the total energy consumption nationally. The concept of NetZero-energy homes (NZEHs) has emerged as a solution to reduce the energy demands of residential building operations. Following efforts to develop NZEHs, the actual energy performance of these homes needs to be examined, and sensor technology is capable of measuring this energy consumption in detail. In this research, sensor instrumentation is customized for NZEH projects developed by Landmark Group of Builders in Edmonton, Canada. Data is collected for the first month and following winter months, then the collected data is validated and cleaned and is analyzed in terms of energy consumption, energy generation, and energy balance. Based on the analysis, recommendations for the operation of NZEHs are proposed
Risk Mitigation through Tolerance Strategies for Design in Modularization
Get PDFCurrent approaches for solving tolerance-related issues in modular construction consist of trial and error tactics, which are inefficient, time-consuming and not risk-averse. Although tolerance management is not new to the construction industry, tolerance issues are usually more problematic for module interfacing and transportation in modular construction. This paper introduces a framework for the development of tolerance strategies for mitigating risks in modular construction systems. Risks affecting specific types of modular projects were investigated and developed into a comprehensive tolerance strategy, which was then validated through a case study of an industrial pipe chassis. The proposed methodology may be more effective than the conventional approach for tolerance definition (i.e., trial and error methods), and has the potential to eliminate rework, decrease project costs and reduce delays experienced in modularization by providing a range of pareto-optimal design solutions for “strict” to “loose” tolerance control with respect to the hypothesized costs and risks
Permanent Modular Construction: Construction Performance
Get PDFThis paper reports on a portion of a study to determine the construction performance of permanent modular construction (PMC) with the goal to verify industry claims of cost and schedule. The research uses a test bed of international PMC case studies. The PMC projects recorded provide a sample to evaluate the performance metrics attributed to off-site construction. The study finds that PMC project samples were 11% more cost effective and 42% improved schedule performance when compared to traditional site built projects
Social Network Analysis of Stakeholder Relationships during Construction Industrialization in China
Get PDFModular and off-site construction has garnered world-wide attention, as evidenced by the gathering momentum of construction industrialization in China. This entails a transition for stakeholders within the construction industry, as construction industrialization will alter relationships among stakeholders on a number of levels. In this research, the stakeholders involved in construction industrialization in China are identified, and the stakeholder relationships are quantified through three surveys. Based on the collected data, the stakeholder relationships are mapped and analyzed using social network analysis. The results indicate that the social network of industrialization construction is not dense and less tied, generates relatively low impacts on the behaviors of individual stakeholders; as the most influential stakeholders, the general contractor, owner, and surveyors and designers control most of the resources; due to their influence in the form of policies, the government can become an important stakeholder during the process of construction industrialization Through strengthening the policy guidance, it can attract new stakeholders for the integrated network, incubate a construction industrialization corporate group with integrated abilities of R&D, design, construction and operation, which is valuable to effectively promote the development of construction industrialization in China
Modularization Business Case Analysis Tool: Learning from Industry Practices
Get PDFModularization is a method of enhancing project value by exporting a portion of site work to fabrication/assembly shops/yards. Maximizing modularization’s benefits, however, is something the industry is still struggling to achieve. To achieve it, the construction industry needs a new modularization business case analysis approach and an associated computational tool. Thus the Construction Industry Institute’s (CII) Research Team (RT) 283 has developed a business case process to identify the optimum proportion of work hours to be moved offsite via module scope; the process also identifies the drivers of modularization. An optimal decision-making process is thereby established. Still missing from modularization business case analysis is a tool to support this process. This study develops just such a tool with the support of the CII Modularization Community of Practice. The tool manages information on module project drivers and, to the different parts of a module job, assigns a cost/factor/productivity. In developing the tool, researchers collected existing business case analysis tools from different companies and from the literature. The most suitable elements from these have been incorporated into a new modularization business case analysis tool. The tool identifies the optimum level of work hours to move offsite, providing specific savings, not just an indicative value. The tool, set up in three layers, permits details to be added and can be used, as a project is further developed, at successive phases with increasing rigor. This tool was subsequently reviewed by CII Modularization Community of Practice. This tool, by selecting optimum level of modularization, should help the construction industry maximize the benefits of modularization
Facilitating Technology Transfer in Offsite Construction Between India and the UK: Drivers and Challenges
Get PDFThe increasing demand for affordable housing in developing countries such as India which mainly uses traditional construction technologies begs the need of technologies that are efficient, low cost, and at the same time high quality. Technologies used by developed nations can meet that need if the transfer could be accomplished efficiently. The purpose of this research is to present findings of a survey and follow-up interviews of senior managers from UK and India to explore the drivers and challenges to facilitate technology transfer in offsite construction between the two countries
Workspace Optimization for Modular Off-site Assembly
Get PDFModular construction is getting more prevalent than the past because it is environmentallyfriendly construction method and it can reduce construction period and cost by manufacturing in factory. Modular unit is produced through assembly line where the intensive manufacturing process is conducted. The manufacturing process is a complicated operation that integrates the production movement with a complex activity precedence network (procedure). Although modular unit production is a sum of the general construction activity superimposed on a production line in modular factory, the activities should be conducted on station for the optimal cycle time and many activities are carried out in the modular unit. So there is spatial constraint in the manufacturing process and modular construction manager suffers from existing limitations such as space, workers, materials which are caused by intensive process. If the manager doesn’t consider the workspace interference when establishing construction process, the efficiency of modular construction would be reduced. The object of this research is to suggest the method which optimize the number of workers for activities on the station and increase the productivity by inputting appropriate number of workers for minimum workspace interference