Modular and Offsite Construction (MOC) Summit Proceedings
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Cost Evolution Throughout the Construction Value Chain
Get PDFThis study is based on the following observation: there is a significant difference between the initial budget forecast and the final budget of construction project. Cost differences in construction projects between the first estimate made by the engagement committee and the actual construction cost at the end of the project are highlighted. Our study therefore focuses on indicators that track the overall cost of a construction project from the client\u27s perspective, in this case the real estate development company. The objectives are as follow: Highlight cost variances in construction projects and analyze the gaps between the initial cost design by customer and final construction. The waste between the "design", “marketing” and "construction" phases is discussed. The paper also quantifies waste in terms of cost between the phases. The analysis reveal that the overall cost evolution is 2.59%, with 0.89% coming from the Construction phase and 1.72% from the Marketing phase, and 0.09% from the Design phase. The results could be of interest to a wide range of researchers working on the interface between the design and construction phases
Decision Support Tool for Enhancing the Economic Impact of Construction using Offsite Systems
Get PDFThe construction industry is facing productivity stagnation across the globe, and several hypotheses to explain this phenomenon exist, most often associated with low use of digitisation, skills shortages and unpredictable market trends. Yet the economic context is more multi-faceted and the different economic drivers are closely interconnected, however research typically addresses each in isolation. This research paper aims to decipher the influence of key economic drivers on the economy, using the UK context as a barometer for international trends, and proposes how offsite technologies with varying levels of value added in the factory may be utilised to mitigate economic challenges. To achieve this, two key objectives were set: firstly to propose a theoretical framework supported by previous research on decision-support for offsite systems; and secondly to develop an infographic style visualisation to express this theoretical framework as an interactive tool. Following from the dual nature of the research objectives, the research employs a mixed methodology rooted in qualitative research techniques dealing with complex subject matters. A robust literature review with associated subsequent framework proposal was the first stage of the research, followed by data visualisation experiments and tools usability trials using focus group methods to collect preliminary data. The results indicated that there was existing evidence upon which to base the theoretical framework for enhancing economic impact using offsite solutions, with six key strands: sustainability, culture, human capital, productivity, digitisation and regulatory. However, the visualisation of this framework into an interactive tool was a novel concept and required an inter-disciplinary approach for data representation. Overall, this paper presents a unique qualitative tool, which can be utilised to simplify the concepts behind offsite construction and the potential economic impact of using offsite. The tool is aimed at decision-makers and stakeholders who may not be familiar with modern methods of construction, and those who would like to prioritise offsite benefits in a given scenario
Open Source Timber Systems as a Democratic Tool for Construction
Get PDFArchitecture, as it exists today, is deeply rooted in perceptions that were established during the Renaissance, which credited the architect as the sole author of creative thinking processes and the resultant design ideas. Since then, the architectural profession has desired to develop new and innovative ways of building, often without being bound by traditions, the environment, or any other constraints and limitations. This approach has frequently failed to address the needs and concerns of many. As a result, architects have not been successful in imparting significant social change that is valuable to large portions of the population. In contrast, however, many other industries have adopted shared design and production practices for the benefit of the masses, warranting further exploration into how architectural practice might evolve its current modes of operation. Wood as a building material has many beneficial characteristics–specifically its widespread availability, versatility, and ease of workability–which make it particularly suitable for investigating shared authorship and collective production methodologies. As an alternative to steel and concrete for mid-rise and high-rise buildings, mass timber construction, in particular, has experienced significant advancements in recent years, resulting in the development of entirely new building processes that rely on innovative engineered wood products, digital manufacturing, and prefabrication techniques. However, this has frequently led to expensive one-off proprietary solutions that are limited in their application. To foster innovation and disseminate knowledge, an open source culture of designing and sharing is necessary. To this end, this paper will present approaches for open source mass timber construction systems that can be applied to a wide range of scenarios and settings, with the aim of ultimately increasing the acceptance and market share of wood construction for the benefit of society at large
Automatic Selection Tool of Quality Control Specifications for Off-site Construction Manufacturing Products: A BIM-based Ontology Model Approach
Get PDFConstruction manufacturing specifications play an important role in assessing quality requirements on a construction project. However, working with these specifications can be overly complicated and error prone to the large amount of regulations and codes that need to be considered and their inter-dependencies. In building information modelling (BIM), the model is a digital representation of a complex construction product and contains precise product information data. The data is currently embedded into the model as properties for parametric building objects that are exchangeable among project operators. Some effort has been previously done to enhance the BIM model to obtain construction-oriented data and linking information that is crucial to manufacturing and quality control and assurance with BIM modelling still remains a challenge. This study proposes an extension to the current BIM-based product-oriented ontology model to include manufacturing processes and inspection, and quality control specifications. By automatically identifying which specifications are applicable to certain products and to extract the requirements imposed, this approach can support and enable automatic decision making in quality inspection and control tasks, which solely depend on information and knowledge from construction specifications. This approach is tested and validated using a light-gauge steel frame wall under Canadian construction standards and regulations
Lateral Performance of Cross-laminated Timber Shear Walls: Analytical and Numerical Investigations
Get PDFCross-laminated timber (CLT) is becoming a viable option for mid-rise buildings in North America. CLT walls are very effective in resisting lateral forces resulting from wind and seismic loads, yet no standard provisions are available to estimate the resistance of CLT shear walls under lateral loading. The present research investigated CLT shear wall’s performance by evaluating the preferred kinematic rocking behaviour. An analytical procedure was proposed to estimate the resistance of CLT shear walls in a platform type construction. Finite element models of CLT shear with various brackets and hold-downs connections were developed. The models were validated against experimental results. Furthermore, a parametric study on CLT shear walls with the variation of type and number of connectors was conducted. The resistance estimated from parametric study and against analytical were compared. The proposed formulas can be useful tool for the design of CLT platform-type buildings, however, require further experimental validation
Transfer Learning Enabled Process Recognition for Module Installation of High-rise Modular Buildings
Get PDFHigh-rise modular buildings (HMB), based on the advanced approach of modular construction, have gained momentum in practice due to their offered benefits in accelerated construction, improved quality, reduced health and safety risks, and enhanced productivity. Modular construction with standard design of modules and repetitive processes of module installation is in favor of the development of construction automation. As module installation is one of the critical activities in the delivery of HMBs, it is important to recognize the module installation process automatically so as to facilitate automation in modular construction. However, there is no detailed phase-division of module installation process. Also, little research has been carried out on intelligent process recognition for module installation due to the limited amount of images of real-life projects. To fill in the knowledge gaps, this paper aims to build a transfer learning enabled process recognition model using convolutional neural network (CNN) for module installation of HMBs. The study first divided the module installation process into three stages: hooking, lifting and positioning, with a comprehensive literature review. Then the recognition model for module installation process was created and trained with the adoption of CNN-based transfer learning, and verified with images taken from real-life projects. The results show that the three stages of module installation process are effectively recognized with the proposed model. The transfer learning enabled image recognition model for module installation process accelerates automation in the construction of HMBs for enhanced productivity and accuracy
Decision-making for Cross-Laminated Timber Modular Construction Logistics Using Discrete Event Simulation
Get PDFModular construction is being touted as one solution to address project delays and cost overruns in the construction industry. Modular construction is a delivery method wherein building components are prefabricated off-site and then transported to the job site for assembly. Thus, prefabrication is a significant element of modular construction that enables work to happen in parallel to accelerate project schedules, enhance safety, and reduce physical work on-site. Timber is becoming a primary material for prefabricating elements since wood is a renewable material, possesses high strength-weight ratio, and sequesters carbon. The use of wood in the form of cross-laminated timber (CLT) introduces new opportunities but also logistical issues in the supply chain from forest to the manufacturing facility to the construction site. Depending on the type of CLT and the level of modularity (i.e., 2D elements or volumetric), major constraints in this process have been identified including (1) fluctuation in the supply of raw wood to manufacturing facilities, (2) limitations in the capacity to create CLT panels, (3) shipping limitations based on allowable loads, and (4) crane availability for assembly of panels on the site. This paper explores the use of simulation models to study the effect of these logistical constraints in modular construction using prefabricated CLT on the total time and hence cost of projects. Specifically, discrete event simulation (DES) will be used to model CLT logistics to identify bottlenecks and provide sensitivity analyses of variables such as lumber supply, travel times, and manufacturing plant capacity on project cost and time. A case study of modular multi-story building construction is examined to showcase the utility of the developed simulation framework. It is expected that simulating modular CLT logistics will enable the identification of optimal strategies towards their successful implementation
Mass Timber in High-Rise Buildings: Modular Design and Construction; Permitting and Contracting Issues
Get PDFDue to the inherent inefficiencies in conventional approaches followed in the construction industry and the global demand for lean and sustainable construction techniques, modular construction has witnessed a resurge especially in high-rise buildings. As such, much efforts have been put in studying the use of mass timber for the main structure of high-rise buildings in order to ensure more sustainable developments with high levels of adaptability. In this regard, previous research efforts have primarily focused on the added benefits of mass timber, its structural design and performance, and associated safety requirements. However, owing to the novelty in combining modular processes with timber materials and associated lack of data, several regulatory barriers and contractual issues still exist. To mitigate these issues, this paper studies the specifics of permit approvals and contracting issues in timber high-rise modular buildings. The objective is to develop a comprehensive up-to-date review and analysis of the relevant practices and to conduct interviews with industry experts to analyze their concerns, given the insufficient number of guides and building codes that dealt with these issues. Hence, our study investigates the process of obtaining permit approvals from local jurisdictions in Ontario in addition to the requirements for submission of additional documentation, engineering analysis, and testing. Moreover, it analyzes the initial stage of contractual agreement of stakeholders under the uncertainties imposed on these buildings and evaluates the suitability of Integrated Project Delivery (IPD) contracting method. Presenting detailed analysis of the initial planning stages for timber high-rise modular buildings can in turn suggest the best practices to be taken into consideration for the successful implementation of these buildings under the current building code
Research on Roles Transformation of Stakeholder in the Industry Chain of Industrialized Building in China Based on Niche Theory
Get PDFConstruction industrialization plays an important role in the development of construction industry, and the stakeholders of the industrial chain are the key factors affecting the development. Therefore, the purpose of this paper is to study the transformation of stakeholders in the construction industrialization industry chain from the perspective of niche theory. Through the method of literature review, the enterprise niche measurement model is studied and established. Then take the case of 59 national housing industrialization base as the verification goal, explore the change law of stakeholders. The results show that the transformation situation of various stakeholders is quite different and related to the Division of labor in the industrial chain
A Knowledge-Based Approach Towards Automated Manufacturing-Centric BIM: Wood Frame Design and Modelling for Light-Frame Buildings
Get PDFBuilding information modelling (BIM) technology has the potential to improve communication among multiple stakeholders and to streamline construction projects. In order for the BIM model to be fit for use in the construction field generally and in modular construction projects specifically, it needs to be designed with sufficient construction details. However, in current practice, this requirement necessitates substantial manual modelling efforts, which limits the use of BIM in the construction field. In this context, the objective of this research is to automate BIM of construction details for modular construction (i.e., manufacturing-centric BIM) with a focus on the wood-framing design and modelling processes. Specifically, this paper presents a portion of the research undertaken at the University of Alberta to develop FrameX, an Autodesk Revit add-on under development for the purpose of automating the framing design of light-frame wood structures. It represents a rule-based modelling approach that is capable of analyzing and designing building frames automatically in accordance with building codes, transportation regulations for modular components, and industry-wide best practices. Various best practice scenarios described in this paper represent ways the industry is seeking to reduce the material, time, and effort required to manufacture prefabricated building panels. A case study is presented to demonstrate the effectiveness of the rule-based modelling approach and the prototyped system, FrameX. The results reveal that the prototype system, FrameX, can automatically output manufacturing-centric BIM model and shop drawings in accordance with formalized rules, to assist field specialists from the outset of a given construction project