Ron Wakefield | RMIT University (original) (raw)
Papers by Ron Wakefield
The Australian construction industry has traditionally relied on 'lagging' indicators of health a... more The Australian construction industry has traditionally relied on 'lagging' indicators of health and safety performance. Lagging indicators, including lost time injury rates, are limited in usefulness because they rely on after the fact recording of statistically low probability events. They are subject to random variation, which can provoke 'knee jerk' reactions immediately following a reportable incident and encourage management complacency when no reportable incidents have occurred for a period of time. An update is provided on the development of a multi-level measurement method, which combines 'leading' safety performance indicators and safety climate measures. It is argued that leading performance indicators and climate measures can (in combination with lagging indicators) provide a more comprehensive analysis of health and safety performance in the construction industry. The opportunities for internal (between project) and external (between organization) benchmarking of health and safety performance are discussed.
The Guide to Best Practice for Safer Construction has been developed following a detailed review ... more The Guide to Best Practice for Safer Construction has been developed following a detailed review of practical Australian and international best practice initiatives. The Guide provides a framework to improve safety performance on construction projects and covers all stages of a project: planning, design, construction and post-construction. Its overarching objective is to reduce the number of accidents and deaths on construction sites and to improve the ability of the industry as a whole to deliver safer construction projects and healthier employees. The three primary stakeholder groups of the construction industry - clients, designers and constructors - have worked together to create a methodology which integrates occupational health and safety into strategic and operational decision-making at all stages of the project. The Guide is intended to be an aspirational document that leads discussion and industry change, as well as a practical tool which can be used across the industry, by clients, designers and constructors and by large firms and small and medium-sized enterprises.
The RMIT Centre for Construction Work Health and Safety provides leading-edge, applied research t... more The RMIT Centre for Construction Work Health and Safety provides leading-edge, applied research to the construction and property industries. Our members are able to work with organisations to analyse health and safety (H&S) performance and identify opportunities for improvement. We can develop and evaluate innovative solutions, provide specialised H&S programs or undertake other research-based consulting activities. Our work addresses real-world H&S challenges and our strong international linkages provide a global perspective to our research.
Identifying a globally optimal solution for an intractable discrete optimization problem is often... more Identifying a globally optimal solution for an intractable discrete optimization problem is often cost prohibitive. Therefore, solutions that are within a predetermined threshold are often acceptable in practice. This dissertation introduces the concept of β-acceptable solutions where β is a predetermined threshold for the objective function value.
Computing in Civil and Building Engineering (2000), 2000
European Journal of Operational Research, 2003
This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard dis... more This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard discrete optimization problem for leveling a construction project site, where the objective is to find a vehicle route that minimizes the total distance traveled by a single earthmoving ...
European Journal of Operational Research, 2003
This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard dis... more This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard discrete optimization problem for leveling a construction project site, where the objective is to find a vehicle route that minimizes the total distance traveled by a single earthmoving ...
Mechanics Based Design of Structures and Machines, 1990
This paper illustrates the application of a general matrix mathematical programming formulation f... more This paper illustrates the application of a general matrix mathematical programming formulation for evaluation of the plastic collapse loads of plane grids under combined bending and torsion. The fundamental theory, based on the application of the static theorem of plasticity to discretized models of both the structure and its material constitutive law, is briefly developed. Two examples, relevant to bridge
Mechanics Based Design of Structures and Machines, 1990
This paper illustrates the application of a general matrix mathematical programming formulation f... more This paper illustrates the application of a general matrix mathematical programming formulation for evaluation of the plastic collapse loads of plane grids under combined bending and torsion. The fundamental theory, based on the application of the static theorem of plasticity to discretized models of both the structure and its material constitutive law, is briefly developed. Two examples, relevant to bridge
International Journal of Mechanical Sciences, 1991
A method for the analysis of elastoplastic structures with large displacements is presented in th... more A method for the analysis of elastoplastic structures with large displacements is presented in this paper. A parametric linear complementarity mathematical programming formulation, in combination with an iterative incremental approach, is used to solve the elastoplastic large displacement problem for assumed piecewise linearized yield conditions. Details of the computational procedure are described along with the steps required for implementation. Several well known examples are solved to demonstrate the accuracy of the method. The influence of different piecewise linearizations of the yield locus on the results is also discussed.
Civil Engineering and Environmental Systems, 1998
An extended stochastic Petri net approach to modelling and simulation of construction systems is ... more An extended stochastic Petri net approach to modelling and simulation of construction systems is developed. The basics of Petri nets, a technique previously used for modelling computer systems and automated manufacturing, are described. Extended stochastic Petri net features useful in construction systems modelling are detailed along with structures that can represent characteristics commonly present in construction systems. Two illustrative examples are presented and the advantages and disadvantages of extended stochastic Petri nets as a tool for construction system modelling are discussed.
Computers & Structures, 1990
An historical deformation analysis method for elastic-perfectly plastic structures which exhibit ... more An historical deformation analysis method for elastic-perfectly plastic structures which exhibit non-unique d~spla~ments is presented. It is based on work by Kaneko, who proposed an elegant mathemati~l programming fo~ulation for nonholonomic elastoplastic analysis. A well known three-bar truss problem is solved in detail to illustrate the application of the present scheme. In particular, it is shown how non-uniqueness of deformation below the collapse limit can be detected, and how the complete admissible displacement field can be generated. Several other examples, solved using MPDEF, a computer program developed by the authors, are briefly presented.
The adoption of e-business by Small and Medium Enterprises (SMEs) in construction lags other serv... more The adoption of e-business by Small and Medium Enterprises (SMEs) in construction lags other service and product businesses within the building sector. Twenty SMEs were studied to establish the drivers and barriers to e-business adoption within construction. Empirical techniques included interviews and repertory grids for business web site assessment. Data were transcribed and analysed using cluster analyses. Preliminary results reveal that current models for e-business adoption are not effective for the small businesses as they tend to target large enterprises or from other sectors such as retail and tourism. These generic models have largely ignored the nature of the construction industry, and some modifications appear to be required. This paper proposes adoption guidelines sensitive to the nature of the industry -particularly for e-business uptake in building SMEs.
Journal of Construction Engineering and Management-asce, 1997
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Canadian Journal of Civil Engineering, 2014
ABSTRACT Construction sites are dynamic environments due to the influence of variables such as ch... more ABSTRACT Construction sites are dynamic environments due to the influence of variables such as changes in design and processes, unsteady demand, and unavailability of trades. These variables adversely affect productivity and can cause an unstable workflow in the network of trade contractors. Previous research on workflow stability in the construction and manufacturing domains has shown the effectiveness of ‘pull’ production or ‘rate driven’ construction. Pull systems authorize the start of construction when a job is completed and leaves the trade contractor network. However, the problem with pull systems is that completion dates are not explicitly considered and therefore additional mechanisms are required to ensure the due date integrity. On this basis, the aim of this investigation is to improve the coordination between output and demand using optimal-sized capacity buffers. Towards this aim, production data of two Australian construction companies were collected and analyzed. Capacity and cost optimizations were conducted to find the optimum buffer that strikes the balance between late completion costs and lost revenue opportunity. Following this, simulation experiments were designed and run to analyze different ‘what-if’ production scenarios. The findings show that capacity buffers enable builders to ensure a desired service level. Size of the capacity buffer is more sensitive to the level of variability in contractor processes than other production variables. This work contributes to the body-of-knowledge by improving production control in constructionanddeploymentof capacity buffers to achieve a stableworkflow.In addition, constructioncompaniescanuse the easy-to-use framework tested in this study to compute the optimal size for capacity buffers that maximizes profit and prevents late completions.
Australasian Journal of Construction Economics and Building, 2010
The Australian house building industry has been facing an increase in the average house completio... more 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 workflowbased 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.
Australasian Journal of Construction Economics and Building, 2013
The construction industry is plagued by long cycle times caused by variability in the supply chai... more 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. The 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.
The Australian construction industry has traditionally relied on 'lagging' indicators of health a... more The Australian construction industry has traditionally relied on 'lagging' indicators of health and safety performance. Lagging indicators, including lost time injury rates, are limited in usefulness because they rely on after the fact recording of statistically low probability events. They are subject to random variation, which can provoke 'knee jerk' reactions immediately following a reportable incident and encourage management complacency when no reportable incidents have occurred for a period of time. An update is provided on the development of a multi-level measurement method, which combines 'leading' safety performance indicators and safety climate measures. It is argued that leading performance indicators and climate measures can (in combination with lagging indicators) provide a more comprehensive analysis of health and safety performance in the construction industry. The opportunities for internal (between project) and external (between organization) benchmarking of health and safety performance are discussed.
The Guide to Best Practice for Safer Construction has been developed following a detailed review ... more The Guide to Best Practice for Safer Construction has been developed following a detailed review of practical Australian and international best practice initiatives. The Guide provides a framework to improve safety performance on construction projects and covers all stages of a project: planning, design, construction and post-construction. Its overarching objective is to reduce the number of accidents and deaths on construction sites and to improve the ability of the industry as a whole to deliver safer construction projects and healthier employees. The three primary stakeholder groups of the construction industry - clients, designers and constructors - have worked together to create a methodology which integrates occupational health and safety into strategic and operational decision-making at all stages of the project. The Guide is intended to be an aspirational document that leads discussion and industry change, as well as a practical tool which can be used across the industry, by clients, designers and constructors and by large firms and small and medium-sized enterprises.
The RMIT Centre for Construction Work Health and Safety provides leading-edge, applied research t... more The RMIT Centre for Construction Work Health and Safety provides leading-edge, applied research to the construction and property industries. Our members are able to work with organisations to analyse health and safety (H&S) performance and identify opportunities for improvement. We can develop and evaluate innovative solutions, provide specialised H&S programs or undertake other research-based consulting activities. Our work addresses real-world H&S challenges and our strong international linkages provide a global perspective to our research.
Identifying a globally optimal solution for an intractable discrete optimization problem is often... more Identifying a globally optimal solution for an intractable discrete optimization problem is often cost prohibitive. Therefore, solutions that are within a predetermined threshold are often acceptable in practice. This dissertation introduces the concept of β-acceptable solutions where β is a predetermined threshold for the objective function value.
Computing in Civil and Building Engineering (2000), 2000
European Journal of Operational Research, 2003
This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard dis... more This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard discrete optimization problem for leveling a construction project site, where the objective is to find a vehicle route that minimizes the total distance traveled by a single earthmoving ...
European Journal of Operational Research, 2003
This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard dis... more This paper introduces the shortest route cut and fill problem (SRCFP). The SRCFP is a NP-hard discrete optimization problem for leveling a construction project site, where the objective is to find a vehicle route that minimizes the total distance traveled by a single earthmoving ...
Mechanics Based Design of Structures and Machines, 1990
This paper illustrates the application of a general matrix mathematical programming formulation f... more This paper illustrates the application of a general matrix mathematical programming formulation for evaluation of the plastic collapse loads of plane grids under combined bending and torsion. The fundamental theory, based on the application of the static theorem of plasticity to discretized models of both the structure and its material constitutive law, is briefly developed. Two examples, relevant to bridge
Mechanics Based Design of Structures and Machines, 1990
This paper illustrates the application of a general matrix mathematical programming formulation f... more This paper illustrates the application of a general matrix mathematical programming formulation for evaluation of the plastic collapse loads of plane grids under combined bending and torsion. The fundamental theory, based on the application of the static theorem of plasticity to discretized models of both the structure and its material constitutive law, is briefly developed. Two examples, relevant to bridge
International Journal of Mechanical Sciences, 1991
A method for the analysis of elastoplastic structures with large displacements is presented in th... more A method for the analysis of elastoplastic structures with large displacements is presented in this paper. A parametric linear complementarity mathematical programming formulation, in combination with an iterative incremental approach, is used to solve the elastoplastic large displacement problem for assumed piecewise linearized yield conditions. Details of the computational procedure are described along with the steps required for implementation. Several well known examples are solved to demonstrate the accuracy of the method. The influence of different piecewise linearizations of the yield locus on the results is also discussed.
Civil Engineering and Environmental Systems, 1998
An extended stochastic Petri net approach to modelling and simulation of construction systems is ... more An extended stochastic Petri net approach to modelling and simulation of construction systems is developed. The basics of Petri nets, a technique previously used for modelling computer systems and automated manufacturing, are described. Extended stochastic Petri net features useful in construction systems modelling are detailed along with structures that can represent characteristics commonly present in construction systems. Two illustrative examples are presented and the advantages and disadvantages of extended stochastic Petri nets as a tool for construction system modelling are discussed.
Computers & Structures, 1990
An historical deformation analysis method for elastic-perfectly plastic structures which exhibit ... more An historical deformation analysis method for elastic-perfectly plastic structures which exhibit non-unique d~spla~ments is presented. It is based on work by Kaneko, who proposed an elegant mathemati~l programming fo~ulation for nonholonomic elastoplastic analysis. A well known three-bar truss problem is solved in detail to illustrate the application of the present scheme. In particular, it is shown how non-uniqueness of deformation below the collapse limit can be detected, and how the complete admissible displacement field can be generated. Several other examples, solved using MPDEF, a computer program developed by the authors, are briefly presented.
The adoption of e-business by Small and Medium Enterprises (SMEs) in construction lags other serv... more The adoption of e-business by Small and Medium Enterprises (SMEs) in construction lags other service and product businesses within the building sector. Twenty SMEs were studied to establish the drivers and barriers to e-business adoption within construction. Empirical techniques included interviews and repertory grids for business web site assessment. Data were transcribed and analysed using cluster analyses. Preliminary results reveal that current models for e-business adoption are not effective for the small businesses as they tend to target large enterprises or from other sectors such as retail and tourism. These generic models have largely ignored the nature of the construction industry, and some modifications appear to be required. This paper proposes adoption guidelines sensitive to the nature of the industry -particularly for e-business uptake in building SMEs.
Journal of Construction Engineering and Management-asce, 1997
RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...
Canadian Journal of Civil Engineering, 2014
ABSTRACT Construction sites are dynamic environments due to the influence of variables such as ch... more ABSTRACT Construction sites are dynamic environments due to the influence of variables such as changes in design and processes, unsteady demand, and unavailability of trades. These variables adversely affect productivity and can cause an unstable workflow in the network of trade contractors. Previous research on workflow stability in the construction and manufacturing domains has shown the effectiveness of ‘pull’ production or ‘rate driven’ construction. Pull systems authorize the start of construction when a job is completed and leaves the trade contractor network. However, the problem with pull systems is that completion dates are not explicitly considered and therefore additional mechanisms are required to ensure the due date integrity. On this basis, the aim of this investigation is to improve the coordination between output and demand using optimal-sized capacity buffers. Towards this aim, production data of two Australian construction companies were collected and analyzed. Capacity and cost optimizations were conducted to find the optimum buffer that strikes the balance between late completion costs and lost revenue opportunity. Following this, simulation experiments were designed and run to analyze different ‘what-if’ production scenarios. The findings show that capacity buffers enable builders to ensure a desired service level. Size of the capacity buffer is more sensitive to the level of variability in contractor processes than other production variables. This work contributes to the body-of-knowledge by improving production control in constructionanddeploymentof capacity buffers to achieve a stableworkflow.In addition, constructioncompaniescanuse the easy-to-use framework tested in this study to compute the optimal size for capacity buffers that maximizes profit and prevents late completions.
Australasian Journal of Construction Economics and Building, 2010
The Australian house building industry has been facing an increase in the average house completio... more 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 workflowbased 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.
Australasian Journal of Construction Economics and Building, 2013
The construction industry is plagued by long cycle times caused by variability in the supply chai... more 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. The 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.