Predicting Australian builders’ intentions to use prefabrication

This study presents the results of the first large scale survey of Australian builders’ beliefs about prefabrication, drawing on 454 surveys completed by representatives of building companies in Queensland and Western Australia. Previous literature has identified a number of broad themes affecting the uptake of prefabrication. The current study builds on this work by using a structured theoretical model based on the Theory of Planned Behaviour (TPB) and the Technology Acceptance Model (TAM), to further explore the specific factors influencing builders’ intentions to increase their use of prefabrication. Information was gathered concerning the characteristics of respondents in addition to three aims. The aims were: (1) To identify the relative importance of a number of key factors which may affect builders’ use of prefabrication, (2) To compare the characteristics of builders using various levels of prefabrication (including none), and; (3) To determine if a model based on the TPB, TAM, and other control variables can explain builders’ intentions to adopt prefabrication on their housing projects.

Cost planning and control : case study of design economics for constructability and prefabrication construction

Cost management includes planning and control, and constructability1 and prefabrication construction are two main design economics factors for early cost planning decision. Despite the fact that constructability and prefabrication have been considered in design and cost planning, there is no guarantee if the intention meets the expectation. This requires on-going control during construction stage. In fact, prefabrication construction has been encouraged for some years, application is not always positive. One of the reasons is its constructability. This paper investigates the appropriate research methodology to determine how design for prefabrication and constructability will contribute to cost planning through control and review during construction stage. Through a study of an Australian residential project using prefabrication in structural concrete, internal partitioning and internal fit-out, this research concludes that case study is a viable choice. Prefabrication construction does provide a positive impact on the major project objectives: time, cost and quality. Cost reduction is due to saving in time related preliminaries as a direct result of time reduction of onsite activities whilst quality is ensured due to better control of prefabricated components inside the factories. However, it can only be achieved after considering constructability: suitable materials choice, design for available skills, use of available plant, and clear communication. The keys are through plan at design phase and control in construction stage.

Gene therapy with adenovirus-mediated VEGF enhances skin flap prefabrication

We investigated the feasibility in rats of enhancing skin-flap prefabrication with subdermal injections of adenovirus-encoding vascular endothelial growth factor (Ad-VEGF). The left saphenous vascular pedicle was used as a source for vascular induction. A peninsular abdominal flap (8 x 8 cm) was elevated as distally based, keeping the epigastric vessels intact on both sides. After the vascular pedicle was tacked underneath the abdominal flap, 34 rats were randomly divided into three groups according to treatment protocol. The implantation site around the pedicle was injected with Ad-VEGF in group I (n = 10), with adenovirus-encoding green fluorescent protein (Ad-GFP) in control group I (n = 14), and with saline in control group II (n = 10). All injections were given subdermally at four points around the implanted vessel by an individual blinded to the treatment protocol. The peninsular flap was sutured in its place, and 4 weeks later, an abdominal island flap based solely on the implanted vessels was elevated. The prefabricated island flap was sutured back, and flap viability was evaluated on day 7. Skin specimens were stained with hematoxylin and eosin for histological evaluation. In two rats from each group, microangiography was performed to visualize the vascularity of the prefabricated flaps. There was a significant increase in survival of prefabricated flaps in the Ad-VEGF group compared to the control groups: Ad-VEGF, 88.9 +/- 6.1% vs. Ad-GFP, 65.6 +/- 9.4% (P < 0.05) and saline, 56.0 +/- 3.4% (P < 0.05). Sections from four prefabricated flaps treated with Ad-GFP revealed multiple sites of shiny deposits of green fluorescent protein around the area of local administration 1 day and 3 weeks after gene therapy. Histological examination done under high-power magnification (x400) with a light microscope revealed increased vascularity and mild inflammation surrounding the implanted vessel in all groups. However, we were unable to demonstrate any significant quantitative difference with respect to vascularity and inflammatory infiltrates in prefabricated flaps treated with Ad-VEGF compared with controls. Microangiographic studies showed increased vascularity around the implanted pedicle, which was similar in all groups. However, vascularization was distributed in a larger area in the prefabricated flaps treated with Ad-VEGF. In this study, the authors demonstrated that adenovirus-mediated VEGF gene therapy increased the survival of prefabricated flaps, suggesting that it may allow prefabrication of larger flaps and have the potential to reduce the time required for flap maturation.

Tissue engineered prefabricated vascularized flaps

BACKGROUND.: Microvascular free tissue transfer has become increasingly popular in the reconstruction of head and neck defects, but it also has its disadvantages. Tissue engineering allows the generation of neo-tissue for implantation, but these tissues are often avascular. We propose to combine tissue-engineering techniques together with flap prefabrication techniques to generate a prefabricated vascularized soft tissue flap. METHODS: Human dermal fibroblasts (HDFs) labeled with fluorescein diacetate were static seeded onto polylactic-co-glycolic acid-collagen (PLGA-c) mesh. Controls were plain PLGA-c mesh. The femoral artery and vein of the nude rat was ligated and used as a vascular carrier for the constructs. After 4 weeks of implantation, the constructs were assessed by gross morphology, routine histology, Masson trichrome, and cell viability determined by green fluorescence. RESULTS: All the constructs maintained their initial shape and dimensions. Angiogenesis was evident in all the constructs with neo-capillary formation within the PLGA-c mesh seen. HDFs proliferated and filled the interyarn spaces of the PLGA-c mesh, while unseeded PLGA-c mesh remained relatively acellular. Cell tracer study indicated that the seeded HDFs remained viable and closely associated to remaining PLGA-c fibers. Collagen formation was more abundant in the constructs seeded with HDFs. CONCLUSIONS: PLGA-c, enveloped by a cell sheet composed of fibroblasts, can serve as a suitable scaffold for generation of a soft tissue flap. A ligated arteriovenous pedicle can serve as a vascular carrier for the generation of a tissue engineered vascularized flap.

Bone response to unloaded titanium implants in the fibula, iliac crest, and scapula: an animal study in the Yorkshire pig

The reconstruction of extended maxillary and mandibular defects with prefabricated free flaps is a two stage procedure, that allows immediate function with implant supported dentures. The appropriate delay between prefabrication and reconstruction depends on the interfacial strength of the bone–implant surface. The purpose of this animal study was to evaluate the removal torque of unloaded titanium implants in the fibula, the scapula and the iliac crest. Ninety implants with a sandblasted and acid-etched (SLA) surface were tested after healing periods of 3, 6, and 12 weeks, respectively. Removal torque values (RTV) were collected using a computerized counterclockwise torque driver. The bicortical anchored 8 mm implants in the fibula revealed values of 63.73 Ncm, 91.50 Ncm, and 101.83 Ncm at 3, 6, and 12 weeks, respectively. The monocortical anchorage in the iliac crest showed values of 71.40 Ncm, 63.14 Ncm, and 61.59 Ncm with 12 mm implants at the corresponding times. The monocortical anchorage in the scapula demonstrated mean RTV of 62.28 Ncm, 97.63 Ncm, and 99.7 Ncm with 12 mm implants at 3, 6, and 12 weeks, respectively. The study showed an increase of removal torque with increasing healing time. The interfacial strength for bicortical anchored 8 mm implants in the fibula was comparable to monocortical anchored 12 mm implants in the iliac crest and the scapula at the corresponding times. The resistance to shear seemed to be determined by the type of anchorage (monocortical vs. bicortical) and the length of the implant with greater amount of bone–implant interface.

Critical sustainability factors in industrialised building systems

Purpose – This paper presents findings of a research study aimed at identifying critical sustainability factors for improved implementation of Industrialised Building Systems (IBS). It also highlights the importance of decision support, through the establishment of decision making guidelines, for sustainability deliverables in IBS development. Design/methodology/approach – A broad range of sustainability factors, as perceived by researchers and practitioners, are identified through a comprehensive literature study. A study of the survey and statistical data analysis is conducted to examine the criticality of these sustainability factors in IBS implementation. Findings – 18 sustainability factors are identified as critical to IBS implementation. Their interrelationships and driving forces are explored, which leads to the development of a conceptual model to map these factors for actions or potential solutions. The work provides a sound basis towards a set of decision making guidelines for sustainable IBS implementation. Originality/value – Compared with previous studies that focus on technical or economical aspects, this study extends existing knowledge on construction prefabrication by linking all aspects of sustainability issues with the design process. It also covers industry characteristics of developing countries, as represented by Malaysia’s scenarios.

An integrated approach to enhance sustainability in industrialised building systems

Building prefabrication is known as Industrialised Building Systems (IBS) in Malaysia. This construction method possesses unique characteristics that are central to sustainable construction. For example, offsite construction enables efficient management of construction wastage by identifying major causes of waste arising during both the design and construction stages. These causes may then be eliminated by the improvement process in IBS component's manufacturing. However, current decisions on using IBS are typically financial driven and hinder the wider ranged adoption. In addition, current IBS misconceptions and the failure of rating schemes in evaluating the sustainability of IBS affect its implementation. A new approach is required to provide better understanding on the sustainability potential of IBS among stakeholders. Such approach should also help project the outcomes of each levels of decision-making to respond to social, economy and environmental challenges. This paper presents interim findings of research aimed at developing a framework for sustainable IBS development and suggests a more holistic approach to achieve sustainability. A framework of embedding sustainability factors is considered in three main phases of IBS construction; 1) Pre-construction, 2) Construction and 3) Post-construction phase. SWOT analysis was used to evaluate the strengths, weaknesses, opportunities and threats involved in the IBS implementations. The action plans are formulated from the analysis of sustainable objectives. This approach will show where and how sustainability should be integrated to improve IBS construction. A mix of quantitative and qualitative methodology was used in this research to explore the potential of IBS in integrating sustainability. The tools used in the study are questionnaires and semi-structured interviews. Outcomes from these tools lead to the identification of viable approaches involving 18 critical factors to improve sustainability in IBS constructions. Finally, guidelines for decision-making are being developed to provide a useful source of information and support to mutual benefit of the stakeholders in integrating sustainability issues and concepts into IBS applications.

Learning landscapes 2.0 : warning - assembly required

Twenty first century learners operate in organic, immersive environments. A pedagogy of student-centred learning is not a recipe for rooms. A contemporary learning environment is like a landscape that grows, morphs, and responds to the pressures of the context and micro-culture. There is no single adaptable solution, nor a suite of off-the-shelf answers; propositions must be customisable and infinitely variable. They must be indeterminate and changeable; based on the creation of learning places, not restrictive or constraining spaces. A sustainable solution will be un-fixed, responsive to the life cycle of the components and materials, able to be manipulated by the users; it will create and construct its own history. Learning occurs as formal education with situational knowledge structures, but also as informal learning, active learning, blended learning social learning, incidental learning, and unintended learning. These are not spatial concepts but socio-cultural patterns of discovery. Individual learning requirements must run free and need to be accommodated as the learner sees fit. The spatial solution must accommodate and enable a full array of learning situations. It is a system not an object. Three major components: 1. The determinate landscape: in-situ concrete 'plate' that is permanent. It predates the other components of the system and remains as a remnant/imprint/fossil after the other components of the system have been relocated. It is a functional learning landscape in its own right; enabling a variety of experiences and activities. 2. The indeterminate landscape: a kit of pre-fabricated 2-D panels assembled in a unique manner at each site to suit the client and context. Manufactured to the principles of design-for-disassembly. A symbiotic barnacle like system that attaches itself to the existing infrastructure through the determinate landscape which acts as a fast growth rhizome. A carapace of protective panels, infinitely variable to create enclosed, semi-enclosed, and open learning places. 3. The stations: pre-fabricated packages of highly-serviced space connected through the determinate landscape. Four main types of stations; wet-room learning centres, dry-room learning centres, ablutions, and low-impact building services. Entirely customised at the factory and delivered to site. The stations can be retro-fitted to suit a new context during relocation. Principles of design for disassembly: material principles • use recycled and recyclable materials • minimise the number of types of materials • no toxic materials • use lightweight materials • avoid secondary finishes • provide identification of material types component principles • minimise/standardise the number of types of components • use mechanical not chemical connections • design for use of common tools and equipment • provide easy access to all components • make component size to suite means of handling • provide built in means of handling • design to realistic tolerances • use a minimum number of connectors and a minimum number of types system principles • design for durability and repeated use • use prefabrication and mass production • provide spare components on site • sustain all assembly and material information

Decision making guidelines for sustainable construction of industrialised building systems

The construction industry has an obligation to respond to sustainability expectations of our society. Solutions that integrate innovative, intelligent and sustainability deliverables are vital for us to meet new and emerging challenges. Industrialised Building Systems (IBS), or known otherwise as prefabrication, employs a combination of ready-made components in the construction of buildings. They promote quality of production, enhance simplification of construction processes and minimise waste. The unique characteristics of this construction method respond well to sustainability. Despite the promises however, IBS has yet to be effectively implemented in Malaysia. There are often misconceptions among key stakeholders about IBS applications. The existing rating schemes fail to assess IBS against sustainability measures. To ensure the capture of full sustainability potential in buildings developed, the critical factors and action plans agreeable to all participants in the development processes need to be identified. Through questionnaire survey, eighteen critical factors relevant to IBS sustainability were identified and encapsulated into a conceptual framework to coordinate a systematic IBS decision making approach. Five categories were used to separate the critical factors into: ecological performance; economic value; social equity and culture; technical quality; and implementation and enforcement. This categorisation extends the "Triple Bottom Lines" to include social, economic, environmental and institutional dimensions. Semi-structured interviews help identify strategies of actions and solutions of potential problems through a SWOT analysis framework. These tools help the decision-makers maximise the opportunities by using available strengths, avoid weaknesses, and diagnose possible threats in the examined issues. The recommendations formed an integrated action plan to present information on what and how to improve sustainability through tackling each critical factor during IBS development. It can be used as part of the project briefing documents for IBS designers. For validation and finalisation the research deliverables, three case studies were conducted. The research fills a current gap by responding to IBS project scenarios in developing countries. It also provides a balanced view for designers to better understand sustainability potential and prioritize attentions to manage sustainability issues in IBS applications.

CIB White Paper on IDDS Integrated Design & Delivery Solutions

CIB is developing a priority theme, now termed Improving Construction and Use through Integrated Design & Delivery Solutions (IDDS). The IDDS working group for this theme adopted the following definition: Integrated Design and Delivery Solutions use collaborative work processes and enhanced skills, with integrated data, information, and knowledge management to minimize structural and process inefficiencies and to enhance the value delivered during design, build, and operation, and across projects. The design, construction, and commissioning sectors have been repeatedly analysed as inefficient and may or may not be quite as bad as portrayed; however, there is unquestionably significant scope for IDDS to improve the delivery of value to clients, stakeholders (including occupants), and society in general, simultaneously driving down cost and time to deliver operational constructed facilities. Although various initiatives developed from computer‐aided design and manufacturing technologies, lean construction, modularization, prefabrication and integrated project delivery are currently being adopted by some sectors and specialisations in construction; IDDS provides the vision for a more holistic future transformation. Successful use of IDDS requires improvements in work processes, technology, and people’s capabilities to span the entire construction lifecycle from conception through design, construction, commissioning, operation, refurbishment/ retrofit and recycling, and considering the building’s interaction with its environment. This vision extends beyond new buildings to encompass modifications and upgrades, particularly those aimed at improved local and area sustainability goals. IDDS will facilitate greater flexibility of design options, work packaging strategies and collaboration with suppliers and trades, which will be essential to meet evolving sustainability targets. As knowledge capture and reuse become prevalent, IDDS best practice should become the norm, rather than the exception.

Reshaping housing using prefabricated systems

Prefabricated housing innovations have the potential to reduce the environmental impact of construction through improvements to efficiency and quality. The current paper presents a number of recommendations for increasing the adoption of prefabrication based on a review of published evidence. The recommendations consider multiple stakeholders including builders and other intermediaries, suppliers, end-users, as well as their interaction with the broader policy context and technical issues

Sustainable innovation for Queensland’s housing design : a case study

This research provides an assessment tool that assists the selection process of sustainability in detached suburban housing. It investigates the implications of using different design and construction methods including architecturally designed houses, developer housing and prefabricated houses. The study simulates one example of the three types of houses that have been chosen to fulfil a real client brief on a real site on the Sunshine Coast, Queensland Australia. Criteria for sustainability assessment are formulated based on literature reviews, exemplar designs and similar research projects for which the houses can be adequately evaluated. This criterion covers aspects including energy use, materials and thermal performance. The data is collected using computer models and sustainability assessment software to compare and draw conclusions on the success of each house. Our study indicates that architecturally designed housing with prefabricated building techniques are a better alternative to generic developer style housing. Our research provides an insight into the implications of three key elements of sustainability including energy use, materials and thermal performance. Designers, builders, developers and home-buyers are given an insight into some options currently available on the housing market and how the choices made during early design stages can provide a more positive environmental impact.

Reshaping housing : the role of prefabricated systems

Prefabricated housing innovations have the potential to reduce the environmental impact of construction through improving efficiency and quality. The current paper systematically summarises the published evidence since 1990 that describes the barriers and drivers affecting the uptake of prefabricated housing innovations. These are discussed in relation to a ‘Project-Based Product Framework’ which considers multiple stakeholders including builders and other intermediaries, suppliers, end-users, the broader policy context and technical issues. The framework facilitated identification of central issues such as the prevalent business and cultural resistance associated with process changes; the potential for efficiency and quality improvements and cost savings; the simultaneous risks and benefits of close supplier-builder relationships, and negative user perceptions towards prefabricated houses. Though there is a lack of evidence regarding the effects of regulations and government policies on prefabrication uptake, there are indications of the positive potential of financial and social incentives. Directions for further research include understanding how to: manage the industry’s transition to prefabricated houses; appropriately compare prefabricated housing to traditional housing on cost, efficiency and quality measures; reconcile the differing perspectives of various stakeholders; quantify and identify the perspectives of the potential end-user population, and manage the interface between the emerging industry and information technology improvements.

Profiling the nature and context of the Australian prefabricated housing industry

The current state of the prefabricated housing market in Australia is systematically profiled, guided by a theoretical systems model. Particular focus is given to two original data collections. The first identifies manufacturers and builders using prefabrication innovations, and the second compares the context for prefabricated housing in Australia with that of key international jurisdictions. The results indicate a small but growing market for prefabricated housing in Australia, often building upon expertise developed through non-residential building applications. The international comparison highlighted the complexity of the interactions between macro policy decisions and historical influences and the uptake of prefabricated housing. The data suggest factors such as the small scale of the Australian market, and a lack of investment in research, development and training have not encouraged prefabrication. A lack of clear regulatory policy surrounding prefabricated housing is common both in Australia and internationally, with local effects in regards to home warranties and housing finance highlighted. Future research should target the continuing lack of consideration of prefabrication from within the housing construction industry, and build upon the research reported in this paper to further quantify the potential end user market and the continuing development of the industry.