Drivers constraints and the future of off-site manufacture in Australia.

Much has been written on Off-site Manufacture (OSM) in construction, particularly regarding the perceived benefits and barriers to implementation. However, very little understanding of the state of OSM in the Australian construction industry exists. A ‘scoping study' has recently been undertaken to determine the ‘state-of-the-art’ of OSM in Australia. This involved several industry workshops, interviews and case studies across four major states of Australia. The study surveyed a range of suppliers across the construction supply-chain, incorporating the civil, commercial and housing segments of the market. This revealed that skills shortages and lack of adequate OSM knowledge are generally the greatest issues facing OSM in Australia. The drivers and constraints that emerged from the research were, in large measure, consistent with those found in the US and UK, although some Australian anomalies are evident, such as the geographical disparity of markets. A comparative analysis with similar studies in the UK and US is reported, illustrating both the drivers and constraints confronting the industry in Australia. OSM uptake into the future is however dependent on many factors, not least of which is a better understanding of the construction process and its associated costs

Knowledge-based energy damage model for evaluating Occupational Health and Safety (OHS) construction risks in Malaysia

The construction industry is renowned as a high-risk industry which involves complex, time consuming design and construction processes characterized by unforeseen circumstances and which has been plagued with accidents for a long time (Ren, 1994). Eliminating the risk of adverse occurrences is essential in order to provide a safe and healthy working environment on construction sites. This paper presents an initial concept for the comparative evaluation of OHS risks for different construction approaches. The model uses a combination of the 'argument tree' concept and 'energy damage model' theory. The assessment process provides a perspective on how the design decisions can impact on OHS for the workers. The 'delivery' stage of two Malaysia housing projects, procured using both conventional and industrialised methods, are utilized to illustrate the model

Building a safety culture: the importance of "shared mental models" in the Australian construction industry

Managers of construction organizations often speak about the inmportance of OHS. Some organizations move beyond the rhetoric to implement OHS management systems, supported by programmes of OHS training and audits. Yet in the face of deadlines or budgetary pressures, managers at all levels of construction organizations sometimes change their priorities to pursue performance in the traditional areas of cost, time and quality - at the expense of OHS. It would be rare for a manager to openly diminish the importance of understanding about how important OHS 'really is'. This paper discusses research currently underway in the Australian construction industry into the role played by managers at different levels in creating OHS sub-cultures in construction organizations. The paper explores how the existence of these sub-cultures should be identified and managed to create shared mental models of OHS within participating organizations

Explaining the Increase in the Australian Average House Completion Time:Activity-based versus Workflow-based Approach

The Australian house building industry has been facing an increase in the average house completion time in the last decade. This increase in some states is quite dramatic. For instance, Western Australia has faced a 70 percent increase in the average house completion time during this period. This paper uses two planning approaches to explain this; i) the activity-based planning methods and ii) the workflow-based planning methods. In addition, this research investigates the strengths and weaknesses of these two planning approaches in explaining the behaviour of the house building industry. For this purpose, a national case study and five state case studies including Victoria, Western Australia, New South Wales, Queensland and South Australia have been used. The data related to the key parameters have been collected and their correlation with the average house completion time has been investigated. These key parameters include the average house floor area, the number of house completions and the number of houses under construction. The reasons for the increasing trend of the average house completion time have been postulated in all case studies. According to this research, the increase in the average house completion time cannot be explained using activity-based planning methods. In contrast, by using workflow-based planning methods, it has been shown that the average house completion time is correlated with the number of houses under construction. This paper shows that the average completion time is influenced directly by the workflow in the house building industry and that workflow planning should be the basis for the house building industry planning

Designing for construction workers' occupational health and safety: A case study of socio-material complexity

Drawing upon an empirical analysis of the design and construction of a food processing facility, a theoretical understanding of the impact of design decision-making on the occupational health and safety (OHS) of construction workers is developed. It is argued that current policy and legislative approaches to Construction Hazard Prevention through Design (CHPtD) are inherently limited because they do not adequately reflect the socio-material complexity of decision-making in construction design. Specifically, the simplistic attribution of responsibility to a single socio-technical actor, 'the designer', does not reflect the multiple and disparate influences that impact upon OHS outcomes. Nor do existing CHPtD policy frameworks, management processes and tools recognize the manner in which the interactions and associations between relevant project stakeholders and various non-human artefacts shape (and are also influenced by) the evolution of design decisions. Drawing on actor-network theory (ANT) and using embedded units within a case study approach, the interactions between human actors and non-human artefacts are explored in relation to the design of four components of the food processing facility. The way in which design decisions unfolded and shaped OHS experiences during the construction stage of the project is revealed. The research highlights limitations inherent in current approaches to the management of CHPtD and the need to develop a more robust theoretically based approach to integrating OHS considerations into construction design practice

The impact of construction commencement intervals on residential production building

One model of operation that production builders can use is continuous construction. They build typical house models and generally work with the same subcontractors. In this continuous operation, an order from the sales department triggers the process, which only commences construction when the first required crew becomes available. In this system the decision to commence construction relies on the readiness of the first activity. However the effects of this decision on the whole construction process are often ignored. This research aims to shed light on the importance of construction commencement decisions by highlighting the consequences of this decision on the whole production system

Do perceptions of supervisors’ safety responses mediate the relationship between perceptions of the organizational safety climate and incident rates in the construction supply chain?

A multilevel safety climate survey was conducted in three Australian organizations in the construction supply chain. A principal components analysis (with varimax rotation) yielded six distinct safety climate factors reflecting aspects of the organizational safety response (OSR), supervisors’ safety response (SSR), and coworkers’ safety response (CSR). Perceptions of top management’s commitment to safety (an aspect of OSR) and supervisors’ safety expectations (an aspect of SSR) were both significantly and inversely correlated with the combined medical treatment and lost time injury rate of workgroups in the analysis. Further, regression analysis revealed that perceptions of supervisors’ safety expectations fully mediated the relationship between perceptions of top management’s commitment to safety and the workgroup injury frequency rate. The results highlight the critical role played by first-level supervisors in acting as the conduit through which organizational safety priorities are communicated to the workforce

Assessing Project Suitability for Off-site Production

Implementation of off-site production on construction projects isoften hindered by a number of specific process and procurementconstraints. These constraints are largely influenced by decisionswithin the control of construction clients, suggesting that theyhave a significant influence over the adoption of off-site productioninto construction projects. However, an appreciation of the effectof these constraints has been lacking. Addressing this need, anoff-site production implementation assessment instrument thatresides within a larger toolkit (IMMPREST) was developed usingquestionnaire survey data and a series of industrial workshops.IMMPREST is an interactive electronic toolkit developed byLoughborough University (UK), in conjunction with eleven industrialpartners, which facilitates the evaluation of benefit arising fromuse of off-site production within construction. It identifies thefactors that need to be considered for an evaluation, the datarequired to assess the effect of these factors, and where therequired data resides within the supply chain. Development ofthe implementation assessment instrument is discussed, whilstalso making reference to the role that clients can play in creatingthe process and procurement conditions that promote rather thanconstrain the adoption of off-site production

A new approach for modelling variability in residential construction projects

The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers

Improving construction productivity: implications of even flow production principles

Subcontracting has been widely used in order to address the high level of variability and associated risks in the complex configuration of residential construction production systems. However, the explosion of subcontracting and the parade of trades have made the construction operations very fragmented, leading to lack of predictability and adequate control on schedules and quality. The present paper proposes a set of system configurations for residential construction. On this basis, after an extensive review of the efforts to model construction production problems, several discrete event simulation models have been developed so as to assess tangible performance measures. Comparing and contrasting the results, two attributes of the system were found to be critical to yield better performance measures. In the proposed flexible system design, fewer cross-trained subcontractors undertake integrated work processes. Also, the number of houses under construction does not grow infinitely and is proportional to the system capacity