Modular and Offsite Construction (MOC) Summit Proceedings
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Numerical Modelling Analysis of Angle Bracket Connections Used in Cross Laminated Timber Constructions
Get PDFConnections are arguably one of the most critical components controlling the structural performance and failure modes of mass timber structures. Over the last two decades, demands for stronger and energy dissipative connections have been raised with increased application of mass timber products in larger and taller buildings. This paper presents numerical analyses of novel mass timber connections used in cross laminated timber structures. The connections are developed by MyTiCon with BB Stanz- und Umformtechnik GmbH angle bracket. Despite being relatively thin, these angle brackets could show comparable load resistance with thicker ones due to the reinforced web and folded edges. The commercially available finite element software ABAQUS was used to develop three dimensional (3D) numerical models to simulate the performance of angle bracket connections under different load combinations. The modelling analysis involves two phases: (1) to determine the most efficient fastener type and setup for the angle brackets connected to CLT wall and floor panels, and (2) to evaluate the capacity of angle brackets connected to CLT wall and floor panels in various loading scenarios. The findings of this study provide an insight into the behaviour of this new angle bracket connections and will be used in the design of the experimental tests in the next phase
Development of Rigging System for Prefabricated Wood I-joist Floor Panels
Get PDFPanelized building construction are highly mechanized. Material handling and lifting equipment dominate construction sites and constitute the critical element in achieving productivity. In recent construction practice, panelized wood I-joist floor panels are normally lifted into place by mobile crane using flexible slings inserted through the predrilled holes on the I-joist web and sheathing panels above the I-joist top flange and then wrapped around the I-joists at the four corners. However, the pre-drilled holes on the web and sheathing may weaken the floor panels. Moreover, a range of techniques for lifting and handling mass timber panels have been developed. A typical rigging technique consists of a lifting ring and a steel plate with pre-drilled holes. By using several self-tapping screws, the panel was connected with the rigging device for lifting. However, since prefabricated I-joist floor panels are much lighter than mass timber panels and the I-joist flange is relatively narrow and thin, the rigging device for mass timber panels cannot be applied directly to I-joist floor panels, but a modified design can be developed for prefabricated I-joist floor panels. In the present study, a new rigging device was designed for prefabricated wood I-joist panels and their load capacity was evaluated by withdrawal tests. Several factors influencing the withdrawal capacity were investigated including screw types and quantities, flange width and materials, and OSB thickness
Characterisation of the Lateral Resistance of Stapled Shear Walls
Get PDFShear walls are the major components of the lateral-force-resisting system (LFRS) in light-frame wood buildings. With the growing popularity of mid-rise prefabricated light-frame wood construction, engineers need basic design information on the shear walls to design and produce safe structures in case of high winds and earthquakes. The racking resistance of light-frame shear walls depends on many factors, including sheathing and hold-down devices and, most importantly, sheathing-to-framing fastenings. While the performance of nailed shear walls has been studied extensively, and design information is included in the design codes, there is little information on stapled shear walls, specifically in the US and Canada. The cost of staples is significantly less than that of equivalent nails; hence, the use of staples instead of nails would allow cost savings in mass production if they provide sufficient resistance and displacement capacity in the engineered shear walls. This paper presents the results of a pilot study which was focused on the comparison of the performance of nailed and stapled shear walls in laboratory tests under monotonic and cyclic loading in accordance with ASTM E564 and E2126, respectively. Several series of tests were performed on 2.4-m (8-ft) square shear walls with 11-mm (7/16-in) OSB sheathing with various hold-downs and various spacing of sheathing staples and nails on the perimeter of the sheathing panels (5-cm (2-in), 10-cm (4-in) and 15-cm (6-in)) and 19-mm and 10-mm edge distances. The staples were 16-gauge (50-mm (2-in) long with 11-mm (7/16-in) crown). The nails were 8d box steel wire nails (63-mm (2½-in) long with 2.87-mm (0.113-in) diameter). The test results revealed a similar performance of the nailed and stapled shear walls, and the need for careful detailing. Therefore, prefabrication of walls in the factory settings is preferable to the on-site construction to allow the production quality control
Numerical and Experimental Study on Modular-Based Timber Structures
Get PDFBuilding with prefabricated light-frame volume modules is a prevalent and innovative construction method for low and mid-rise timber buildings. Compared to traditionally site-built constructions this method is very advantageous due to its high prefabrication level and the fast on-site assembly of the modules. The focus of this project is to study and optimise the global shear stiffness of the volume modules and to secure a large enough shear and uplift stiffness of the mechanical (or friction based) connections between the modules. Some companies assume that the friction between the modules is sufficient to transfer the wind stabilization forces down through the entire building. Regarding structural safety, connection design is an important task that needs to be numerically studied and experimentally verified. The paper presents numerical and experimental results obtained from two ongoing research projects concerning modular-based timber buildings in Sweden. The final aim of this work is to develop an efficient three dimensional finite-element model to analyse both the global and detailed structural behaviour of these types of buildings. To study the overall shear stiffness of the volume modules, eight different test-modules are to be tested. The test results will be used to calibrate the numerical model
Developing an Analytical Solution that Mimics Simulation Modeling for Construction Planning: Earthwork Case
Get PDFDeriving a reliable earthwork job cost estimate entails analysis of the interaction of numerous variables defined in a highly complex and dynamic system. Using simulation to plan earthwork haul jobs delivers high accuracy in cost estimating. However, given practical limitations of time and expertise, simulation remains prohibitively expensive and rarely applied in the construction field. The development of a pragmatic tool for field applications that would mimic simulation-derived results while consuming less time was thus warranted. In this research, a spreadsheet based analytical tool was developed using data from industry benchmark databases (such as CAT Handbook and RSMeans). Based on a case study, the proposed methodology outperformed commonly used estimating methods and compared closely to the results obtained from simulation in controlled experiments
Case Study: Program Management of Volume Modules
Get PDFVolume module systems in the refining and petrochemical industries are large, multi-level systems that are fabricated offsite and stacked onsite, with integral piping and wiring interconnections. This is a case study in a program management system that was introduced for a particular volume module system. Modular design and fabrication suffer from inherent shortcomings: it is neither cheap nor fast nor does it result in any meaningful increase in quality. Lessons learned reveal cheaper, faster and better methods that overcome the inherent shortcomings of modular design and construction. These lessons can inform current trends in modular design and fabrication in the USA and Canada
A Survey on Information Flow Tools in Alberta’s Construction Industry
Get PDFConstruction is a major industry in Alberta due to its significant contribution to GDP and employment. Poor communication and inadequate information flow can lead to poor performance on construction projects, in terms of cost, schedule, and quality. Construction 4.0 promotes the implementation of modern information technologies to encourage the digitization of the construction industry and its supply chain. Efficient information flow in the construction supply chain is key for enabling Construction 4.0 and improving the performance of construction projects. This study presents the results of a survey on tools currently used in Alberta’s construction industry to exchange information. Results show that Alberta’s construction industry mainly depends on emails, meetings, and phone calls to exchange information among stakeholders. These tools are shown to be inefficient means of communication because of delays they arise in providing information, and because of their limitations in storing and disseminating information, which hinders knowledge creation and innovation
Strategies for Building Information Modelling Adoption in the South African Construction Industry
Get PDFThe present state of the construction industry worldwide requires continual improvement. The quest for improvement is to the advantage of all concerned stakeholders. Innovation has been identified as this improvement measure. Building Information Model (BIM) is an example of such innovation in the construction industry. This work presents the strategies required for full adoption of BIM among construction professionals in South Africa. The study conducted a questionnaire survey among construction professionals in Gauteng province, South Africa. Data gathered were analyzed using percentage, mean item score and Kruskal-Wallis H-Test. The reliability of the questionnaire was also determined using Cronbach-alpha test. Embracing BIM requirements in construction supply chain, encouraging stakeholders collaboration, clear understanding of procurement process, and interpretation of accurate information are identified as key strategies for proper BIM adoption in for construction activities in South Afric
A BIM-based Supply Chain Integration for Prefabrication and Modularization
Get PDFPrefabrication and modularization helps to reduce cost and schedule time for on-site activities. The use of Building Information Modeling (BIM) helps to improve collaboration and improve the construction process. The improved installation precision provided by BIM Model-Driven Prefabrication can decrease on-site labor time and increase productivity. Prefabrication, Modularization, and off-site construction transfers activities that would have been performed on site to earlier stages of the supply chain. The implementation of Just-In-Time (JIT) delivery transfers the costs and risks associated with inventory to the supplier. Construction Supply Chain Integration can help reduce cost and waste across the supply chain particularly for large and complex buildings. This paper presents a methodology that utilizes a BIM based construction supply chain integration to reduce cost and waste in the construction and offsite manufacturing processes. It utilizes the integration of BIM with the on-site schedule and the manufacturing or fabrication schedule of the different supply chain members. The methodology utilizes the onsite schedule, lead times of prefabricated elements or modules and the transportation logistics to help reduce cost across the supply chain. The information, material and cash flows as well as the transportation logistics is utilized in generating an optimized just-in-time delivery schedule for large and complex buildings. The optimized delivery schedule takes into account the variations in the on-site and off-site schedules to forecast delivery dates of precast elements or fabricated modules
IoT-based Inventory Control System Framework for Panelized Construction
Get PDFModular construction and panelized construction have been promoted and recognized globally as advanced construction techniques. Not only have these construction methods been utilized in the oil and gas industry, but they have also successfully been introduced into the residential construction industry. In North America, the panelized construction technique has become popular particularly for wood-frame wall panels. However, although utilizing this advanced construction method can greatly improve the working environment and productivity, the conventional mentality in construction, which overlooks the value of an automated management system to support offsite prefabrication and onsite installation, hinders its potential. An Internet of Things (IoT)-based management system can capture all dynamic data in real time and effectively synthesize it along the supply chain associated with various types of resources. Eventually, with the assistance of a feature-based modeling method, IoT-based information collection can be merged into an Enterprise Resource Planning (ERP) system. Although highly dynamic market demands result in continual changes in the production plan, schedule, and inventory levels, adopting an IoT-based system accounts for the dynamic changes characteristic of this advanced construction method in order to maximize production. Therefore, in this paper, a conceptual framework for an IoT-based inventory control system is proposed in order to enhance the production and satisfy Just-in-Time inventory principle. IoT-based real-time technology is introduced and the development of supportive software is described. Part of the proposed IoT-based inventory control system is implemented as a case study in a panelized construction manufacturing facility, ACQBUILT, Inc., based in Edmonton, Alberta, Canada