Modular and Offsite Construction (MOC) Summit Proceedings
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Modelling and analysis of two production solutions for precast concrete elements: A Petri-nets approach
Get PDFThe adoption of precast concrete construction has been increasingly emphasised globally, due to its advancements in productivity, waste management, cost control, quality and safety. Meanwhile, the production solutions differ greatly in the off-site plants in terms of traditional stationary production and modern circulation production with different levels of automation. Practical cases show that improper selection or upgrade of production solution could lead to resource slack or even business failure, and there is limited knowledge to quantitively support the decision making. Furthermore, existing works seldom dig deep into the fundamental setup of the production plant, and reckon without the stochasticity and variability of production operation. Therefore, this paper aims to develop an analytical model to facilitate the understanding of the production solutions of precast concrete elements, which should further support the decision making in factory planning or upgrade towards increased level of automation. Stochastic Petri-nets approach has been applied, with stochastic features embraced, to graphically modelled stationary and circulation solutions. Simulation and comparative performance analysis was conducted with a numerical case study. Results demonstrate that stationary solution can achieve even higher outputs during production period provided that enough resources are given, whilst circulation solution has a more flexible and stable production
Behaviour of ultra-high performance fibre reinforced concrete beam-column joint under cyclic loading
Get PDFUltra-high performance fibre reinforced concrete (UHPFRC) has very high compressive strength up to 200 MPa and exhibits strain hardening effects under flexural loading. The bond strength between UHPFRC and steel reinforcement is much better than the normal strength concrete. Therefore, there is a potential to use UHPFRC material at the beam-column joint region to reduce the congestion of reinforcement as well as to improve the seismic resistance of the structure. In this pilot study, the beam column joints made of normal strength concrete and UHPFRC were tested under lateral cyclic loading up to failure using a 500 tonne capacity computer control servo hydraulic machine. The specimen with normal strength concrete failed at the joint region while the specimen with UHPFRC material failed due to yielding of the rebars in the beam sections near the column face and no obvious cracks were observed at the joint area. The specimens with UHPFRC as joint material exhibited higher initial lateral stiffness and achieved slightly higher ultimate load capacity than the specimen with normal strength concrete
Comparing cross laminated timber with concrete and steel: A financial analysis of two buildings in Australia
Get PDFThis research paper undertakes a comparative financial analysis of the performance of a Cross Laminated Timber (CLT) apartment building with a concrete and steel apartment building constructed in Australia. A product known as CLT has been found to be an effective alternative form of construction to building with the more traditional materials of concrete and steel. CLT can assist in reducing carbon emissions through carbon sequestration. Respective revenue, time and cost variables are calculated, analysed and compared per development. Financial modelling of these variables results in; Development Margin, Development Profit, Return on Equity (ROE) and Equity Internal Rate of Return (IRR). These figures are performance indicators used to appraise the development. The study supports the economic benefits when comparing CLT to concrete and steel construction. It is concluded that building with CLT may result in less development profit and margin, but an increased Equity IRR due to a reduced investment timeline
Key technologies for prefabricated timber buildings
Get PDFNowadays, Chinese government has enacted a series of regulations and policies to increase the prefabrication level in building constructions. Timber structures are featured by the characteristic of a high level of prefabrication. A lot of attention has been paid on the research and application of prefabricated timber buildings recently. This paper presents a brief introduction of the structural systems and key technologies for prefabricated timber buildings. A few case studies on multi-story timber or timber-hybrid buildings are analysed with the emphasis on introducing their structural system and the respective construction techniques. The objective is to provide selected examples to explore the possible strategies with the understanding that prefabricated construction is an organizational process based on a steady flow of stages of the whole construction process. The current knowledge gaps are identified and discussed, concerning the industrialization process and an increasing degree of assembling. Furthermore, future opportunities for prefabricated timber buildings have been put forward
A study on small-world characteristics of Chinaäó»s high-speed railway networks
Get PDFThe small-world model provides a useful perspective and method to study the topological structure and intrinsic characteristics of high-speed rail networks (HRNs). In this paper, the P-space method is used to examine global and local HRNs in China, meanwhile the adjacency matrix is developed, then the social network analysis and visualization tool UCINET is used to calculate the spatial and attribute data of HRNs at national and local levels in China. The small-world characteristics of whole HRNs are discussed, three networks which have different properties are determined, and a comparative analysis of the small-world effect is detected. Then, the relationship between the construction of high-speed rail and regional development of China is analysed. The results show that: 1) China\u27s HRNs have small average path length ( L ) and large clustering coefficient (C ), representing a typical small-world network; 2) Local HRNs have a certain correlation with economic development. The reasons for the difference of HRNs with respect to characteristics among regions are eventually discussed
Front matter, 2016 MOC Summit proceedings
No full textProceedings of the 2016 Modular and Offsite Construction (MOC) Summit held in Edmonton, Alberta, Canada, September 29 - October 1, 2016
Improving Efficiency of Underground Heat Storage Systems
Get PDFUnderground thermal energy storage (UTES) systems are very popular in Europe and are gaining popularity in North America. The first large-scale solar borehole thermal energy storage (UTES) system in Canada has been implemented in the town of Okotoks (McClenahan D, 2006). The second UTES project in Alberta is located in the community of Southwoods in Edmonton (Kantrowitz T. et al., 2013), which proposes to use natural gas cogenerators to generate electricity and heat during the winter to improve electricity generation efficiency and hence reduce overall energy costs. During the generation of electricity, unused heat can be collected and used to heat space and water for domestic use. During the summer, the electrical output from cogeneration exceeds demand, resulting in a seasonal and annual thermal imbalance which UTES can control through the transfer and storage of the excess heat to a UTES system. Most soils in the Edmonton region consist of sandy clays with high moisture content and high thermo-conductivity. Thus, storing heat in such soils would be inefficient since most of the heat would escape before it could be used for heating purposes. However, if such soils could be modified to become good insulators via innovations in jet grouting and soilcrete technologies, UTES systems could become more prevalent as a renewable energy source in areas with highly thermo-conductive soils. This paper proposes to develop the jet grouting and soilcrete theory and conceptual models required to create an insulated enclosure around UTES systems in highly thermo-conductive soils
Analysis framework of off-site manufacturing solutions : case study of a powerhouse complex
Get PDFThe quest for improved productivity and optimized construction costs are continuously challenging the industry. The experience gained from the manufacturing industry showed that off-site manufacturing appears to be a promising alternative to the classic way of building a powerhouse complex. However, ingularity of projects, sizes of powerhouse complexes and multiplicity of stakeholders greatly impact the integration of such practices. To fully assess the benefits of off-site manufacturing, and to guarantee its integration within the project, it is essential to understand the issues in order to characterize benefits related to construction projects in remote areas. In this paper, the research explores off-site manufacturing integration in the industrial context of a major Canadian utility company. One of the goals is to reduce the duration and costs of construction of a future powerhouse complex project through the use of off-site fabrication. The objective of this research is to maximize these benefits of off-site fabrication through the identification of the best available strategies. To do this, a strategic analysis is conducted to evaluate off-site fabrication impact over current processes. Then, an economic analysis estimates
the benefits of potential decisions made during the engineering phase. This research contributes to the construction industry by proposing an analysis framework for the identification of off-site manufacturing solutions in the context of a powerhouse complex project
Industrializing Korean Traditional Housing (Hanok) with Hybrid Timber Construction
Get PDFIn an attempt to disseminate traditional Korean culture, a comprehensive research has been initiated by Korean government in order to modernize Korean traditional housing (Hanok) with the objectives of improved energy performance and affordable construction cost. This äóÖHanokäó» project encompasses a wide spectrum of housing research including public policies, planning methods, standard design documents, new building materials and methods, construction standards, maintenance manuals, and advanced IT applications in an integrated manner. One of the biggest challenges in this äóÖHanokäó» project was to modernize the äóÖtraditional timber structureäó» for industrialization, while keeping the traditional way of aesthetic representation. As a solution to meet this complicated requirement, a hybrid timber system was developed by combining traditional methods and industrialized modular members. Different timbers and methods are used together for different part of house elements resulting in cost reduction by 50% for the timber frame. Major criteria for applying different methods include the aesthetic representation, economy, and deformation behaviour of wood. Automated computer numeric control (CNC) machine, standard 3D-CAD objects, standard classifications, and computer applications were also developed in order to make this hybrid system economically feasible. This paper introduces the hybrid timber system for Hanok along with supportive application systems for industrialization. Three mock-up projects, actually built as part of this research project, are compared and analysed in order to illustrate how the proposed hybrid timber system has evolved during the research and development. Lessons learned and future directions will be also briefly discussed
Implementing Sustainable Construction Principles and Practices by Key Stakeholders
Get PDFThe term äóÖsustainable constructionäó» is used to highlight the responsibility of the construction industry in attaining sustainable development (SD). With the increasing necessity for resource efficiency and climate change adaptation, there is a need for construction key stakeholders to implement sustainable principles and practices in construction projects. In the UK context, engaging in such action will facilitate the government target of 80% greenhouse gas reduction by 2050 and also be a potential source of competitive advantage in the future. The aim of this study is to examine how the industry values and promotes sustainable principles and practices in construction projects. A quantitative research method was adopted in order to reach a wider audience in the industry. An online questionnaire survey was used to collect data. The key finding from the survey is that the level of construction industry promotion of
sustainable principles and practices is less than it should be. The outcome of the survey suggests that the industry needs to strategise on how to champion and promote the implementation of sustainable principles and practices at a greater level if the industry is to contribute to the global quest for SD