Handling construction pollutions using multi‐objective optimization

Quantitative assessment of emissions associated with construction projects should be carried out during the planning phase of the projects. This is important to detect and highlight any excesses of residuals during the construction phase. A newly developed framework is proposed to handle construction pollution using multi‐objective optimization. The approach, utilized by the proposed framework, is based on calculating the generated pollution for each activity involved in the project, as a result of dust, harmful gases and noise. The results of the quantitative assessment are integrated in a utility function that expresses the amount of total pollution. Then, evolutionary genetic algorithms (GAs) are used to carry multi‐objective optimization, considering three objective functions (project duration, project cost and total pollution). The proposed application considers the dynamic nature of construction activities including different types of relationships and the change of activities' criticality. An actual case study is worked out to demonstrate the practical use of the proposed framework and to investigate the sensitivity of its parameters.     

The work‐life experiences of office and site‐based employees in the Australian construction industry

A survey was conducted among employees of a large Australian construction firm. Comparisons were made between employees who differed by gender and work location. Male employees in site‐based roles reported significantly higher levels of work to family conflict and emotional exhaustion than male employees who worked in the regional or head office. Site‐based male employees were also less satisfied with their pay than male respondents who worked in the regional of head office. Few significant differences were found between women who worked in different locations. Neither were significant differences between men and women who worked in the same location reported. The results are explained in terms of women's tendency to work in administrative, secretarial or support services roles, which typically demand fewer hours. The paper concludes that the experiences of site‐based construction employees, particularly men, warrant further attention to explore the sources of work‐life imbalance and burnout.     

A competency‐based performance model for construction project managers

The role of competency‐based performance management is growing in significance in many industries and sectors. Unlike functional competences, which measure performance against predetermined minimum occupational standards, competency‐based systems are founded on the key behavioural competencies that underlie superior levels of performance. In order to identify the key behaviours leading to performance excellence amongst construction project managers, in‐depth behavioural event interviews were used in which managers were asked to recount critical management incidents, decisions and actions from which their behavioural competencies could be identified. By delineating the sample according to their performance against a range of role‐based criteria, the competencies defining superior management performance were determined. Statistical techniques were then used to develop a model that can be used to predict likely employee performance, which was subsequently validated on a second criterion sample. The research identifies 12 core behavioural competencies that underpin effective project management performance, of which two – ‘composure’ and ‘team leadership’ – were the most predictive. The paper explores the potential role and application of the framework in the drive for performance excellence within the industry, such as in selection, management development, succession planning, performance management and team deployment. It is argued that it offers an innovative alternative to normative micro‐competence‐based approaches that do little to engender performance excellence amongst the industry's key managers and professionals.     

A case‐based reasoning approach to application of value engineering methodology in the construction industry

A key point in value engineering (VE) methodology is to acquire and apply knowledge of the assorted fields. An appropriate definition of VE expert knowledge flow could, therefore, yield more productive VE workshops. A conceptual expert case‐based reasoning (CBR) framework is introduced in this paper to form a coherent basis for the provision of practically suitable VE expert models. The proposed framework outlines knowledge entities and their relations in the VE workshop. The model benefits from a fuzzy approach to handle uncertainties in the evaluation phase of the methodology. In addition, a computer program is devised, based on the proposed framework, using Borland Delphi 7.0. It comprises an interface representing several phases of the VE job plan. The model is employed in a tunnelling project to demonstrate feasibility of the model in a practical workshop. Owing to its expert nature, the developed model contributes to efficiency of the methodology through providing VE teams with canalized expert knowledge of diverse domains. The propounded model may avail researchers in promoting expert models for pre‐construction and specifically VE studies in major construction projects.     

Benefit evaluation for off‐site production in construction

Evaluating to what extent a component or building system should be produced off‐site is inadequate within the industry. The potential benefits of off‐site production (OSP) are commonly cited when justifying an OSP approach, yet holistic and methodical assessments of the applicability and overall benefit of these solutions, to a particular project, have been found to be deficient. Common methods of evaluation simply take material, labour and transportation costs into account when comparing various options, often disregarding other cost‐related items such as site facilities, crane use and rectification of works. These cost factors are usually buried within the nebulous preliminaries figure, with little reference to the building approach taken. Further, softer issues such as health and safety, effects on management and process benefits are either implicit or disregarded within these comparison exercises. Yet it is demonstrated that these issues are some of the most significant benefits of OSP. A series of case studies demonstrated that evaluation focus is almost solely on direct material and labour costs of components, without explicit regard for the wider cost or soft issue implications of OSP on a project. The paper argues that until evaluation is more holistic and value‐based rather than cost‐based, OSP uptake in construction will be slow.     

Group‐level safety climate in the Australian construction industry: within‐group homogeneity and between‐group differences in road construction and maintenance

In modern organizations it is overly simplistic to assume that a uniform, organization‐wide climate for safety develops. Workgroup‐level safety climates are more likely to arise in decentralized organizations and their influence on occupational health and safety (OHS) behaviour is likely to be stronger when work is non‐routine, as in construction. The existence of workgroup‐level safety climates was examined in the Australian construction industry. A group‐level safety climate survey was conducted in a road maintenance and construction organization. The clear factorial structure produced in a larger sample of Australian defence logistics workers was not replicated and factors splintered, possibly due to the subject‐to‐item ratio in the construction study. However, the internal reliability consistency of the factors produced in the earlier pilot study was found to be acceptable for the construction industry data. Two requisite conditions for the existence of group‐level safety climates, i.e. (1) within‐group homogeneity; and (2) between‐group variation, were satisfied within the road construction and maintenance organization. The results indicate that distinct workgroup safety climates exist in construction, providing a theoretical explanation for why some workgroups perform better in OHS than others, despite having similar risk exposure.     

Decision‐making in a model‐based design process

Decisions early in the design process have a big impact on the life cycle performance of a building. The outcome of a construction project can be improved if different design options can rapidly be analysed to assist the client and design team in making informed decisions in the design process. A model‐based design approach can facilitate the decision‐making process if the design alternatives' performances can be evaluated and compared. A decision‐making framework using a performance‐based design process in the early design phase is proposed. It is developed to support decision‐makers to take informed decisions regarding the life cycle performance of a building. A scenario is developed in order to demonstrate the proposed framework of evaluating the different design alternatives' energy performance. The framework is applicable to decision‐making in a structured design process, where design alternatives consisting of both objective and subjective evaluation criteria can be evaluated.     

A model for smoothing time‐series data in construction

The understanding of the behaviour of time‐series data has been a matter of concern to researchers and practitioners in a variety of fields ranging from social science and economics to engineering. Also, the behaviour of many phenomena within fields relating and peripheral to construction is described as a time series. Typically, the time‐series analysis is carried out in order to forecast the future values of the series. These techniques, however, are also used to abstract the generalities within the series, hence facilitating the replication of the entire profile, reflecting only the main characteristics of the profile. There is a variety of techniques that can be applied to a set of time‐related data. The choice of the technique is, therefore, dependent on the nature of the problem and the characteristics of the data. The diversity of available techniques is, on the one hand an advantage for all analysts. However, this diversity is also an indication that there is no universal technique that is applicable to a diversity of time‐series data.

This work fundamentally addresses the issue of smoothing and curve‐fitting techniques rather than predicting and forecasting. A technique is offered which is tested against a set of criteria that are designed to focus on the accuracy of imitation and the practicality of operation: the ability to deal with a large number of time‐series sets of data in a consistent, replicable and automated way. The viability of the technique is demonstrated by its application to expenditure profiles of a large number of construction projects. The size of the sample and the diversity in the profiles of the expenditure patterns provided an appropriate testing ground for the universality of the model.

The results indicated that the model can effectively transform a jagged time series into a smooth pattern, while complying with a set of criteria many of which are common to several other research works relating to time‐series data analysis. The proposed technique sequences a number of basic smoothing methods and the process involves the treatment and incorporation of the residual values.     

Interpersonal trust and inter‐firm trust in construction projects

Working relationships are important in effecting project performance and cooperation is believed to be a behavioural consequence of trust. Trust, being a quality of relationships, involves people interacting at interpersonal and inter‐firm levels. This is investigated through 10 partnering and non‐partnering projects, using a validated trust scale. A case study approach is used to collect qualitative data through a quantitative approach to help understand the concept of trust. Data were collected from clients, contractors, consultants and subcontractors. Clients and contractors have a tendency to trust individuals whereas contractors and subcontractors have a tendency to trust firms. Inter‐firm trust is better understood than interpersonal trust; but both are associated with keeping commitments and demonstrating cooperation, even though interpersonal trust is considered more important. Partnering does not necessarily exhibit more trust than non‐partnering projects whereas clients and contractors have different emphasis on interpersonal and inter‐firm trust. Therefore, to promote trusting relationships in multi‐parties is to fulfil not only the technological and economical goals, but also the moral and social goals as expressed in people relationships such that a socially safe working place can be created. For this reason, middle managers need to know about trust because they face more relationship problems than others.     

Urban aesthetics and the discovery of the urban fabric in turn‐of‐the‐century Germany

Approaches to planning that developed in the later nineteenth century in Germany (and in Europe generally) were challenged on aesthetic grounds at the end of the century by Camillo Sitte and others. By the turn of the century, practitioners of planning had embraced Sitte's views on a number of matters. Among the changes that occurred were an end to the disencumbering of monumental buildings and a greatly expanded interest in historic preservation. This was not simply a matter of aesthetics gaining more influence over planning practice, however. Sitte's desire to develop systematically the aesthetic dimension of planning was shared by earlier theorists, notably Hermann Maertens, who endorsed many of the practices Sitte rejected. Ultimately, the compatibility of the new aesthetics with more practical needs was crucial to its acceptance. The new interest in historical models reflected an understanding of urban form that enabled planners to reconcile their aesthetic goals with other needs.     

A performance‐based bridge LCCA model using visual inspection inventory data

Since most bridge life cycle cost analysis (LCCA) depends heavily on the analyst's experience to determine the times and costs of remedial actions over a bridge's lifetime, the results are often subject to question because of their subjectivity. While some work has been done over the years to develop reliable deterioration models for determining such times and costs, the proposed models often require sophisticated inspection data, which is costly to obtain, and/or complex mathematical calculations. A simple linear deterioration model based on visual inspection inventory data concerning bridge components is introduced and integrated into the LCC analysis. The proposed model provides an alternative approach to bridge LCC analysis that can improve the objectivity of analysis and does not require input of sophisticated inspection, and thus facilitates application of bridge life cycle cost analysis. The LCCA method developed in this study is applied to a case study of alternative PCI (Pre‐stressed Concrete I‐girder) and a PCB (Pre‐stressed Concrete Box‐girder) bridges for the purpose of model validation.     

Impact of pre‐construction planning and project characteristics on performance in the US electrical construction industry

The mild recession experienced in the early part of this decade forced many US electrical contractors to reduce their profit margins as a way to win jobs and survive economically. However, to make up for lower profit margins, contractors turned to ‘better planning’ as a method for improving their efficiency and increasing their profitability. In general, contractors believe that better planning contributes to better project performance, but the evidence has been mostly anecdotal. A study was conducted recently that transformed anecdotal evidence about the impact of pre‐construction planning on performance into quantitative evidence. The research resulted in the development of a model pre‐construction planning process that was based on outstanding projects that were well planned and performed well. The study quantified the relationship between pre‐construction planning activities, project characteristics and performance, and a separate validation study found that those projects that performed a comprehensive planning process similar to the model planning process were more likely to achieve their estimated work hours, profit, budget and completion goals.     

Exploring the drivers of firm‐level innovation in the construction industry

A survey of 335 businesses in the Australian road industry has been carried out to ascertain those factors that make firms innovate. ‘Innovative’ is measured by adoption rates of advanced technologies and practices, and the range of innovation drivers reviewed encompasses business strategy and environment. The findings indicate that business strategies are more important than business conditions, and that the following three strategies are significant in differentiating between firms with high and low adoption rates: (1) hiring new graduates; (2) introducing new technologies; and (3) enhancing technical capabilities. The findings also highlight the importance of undertaking R&D and encouraging employee ideas for improvement. The public policy implications are that the quality of university graduates should be protected and advanced, as should technical skills within public sector client agencies.     

Performance‐Based Contracting: an alternative approach to transacting in construction

Cost versus quality has often been presented as if it were a zero sum game — ‘If I gain in terms of quality then I will hare to lose in terms of the money I need to spend’.In reality most design teams would contend that this is not necessarily true but find that they lack the technique to evaluate the proper balance between cost and quality in order to achieve value for their client. This paper outlines the problem and a possible framework for investigating a marginal increase in design quality against cost at the critical stage before drawn information is provided.     

Automated trade‐off between time and cost in planning repetitive construction projects

An automated model is developed to support the optimization of the planning and scheduling of repetitive construction projects. The model provides the capability of optimizing two important objectives commonly sought in scheduling repetitive construction projects: minimizing project duration; and minimizing project cost. The model performs this multi‐objective optimization using a genetic algorithm approach. The output of the model is a set of optimal solutions that represent the trade‐off between time and cost in planning repetitive construction projects. Furthermore, the model can be utilized to find a single scheduling solution that provides the minimum overall project cost by simply adding project indirect cost to the obtained project direct cost for each of the obtained scheduling solutions on the Pareto optimal curve. Other important time‐related costs are also considered in the model including: early completion incentives, late completion penalties and lane rental costs. Providing the planners of repetitive construction projects with an automated set of optimal time–cost trade‐off solutions should contribute to cost‐effective and speedy delivery of this type of construction project. An application example is analysed to illustrate the use of the model and demonstrate its capabilities in generating optimal trade‐off solutions between minimizing the project time and cost for repetitive construction projects.     

Safety climate in conditions of construction subcontracting: a multi‐level analysis

A multi‐level safety climate model was tested in the Australian construction industry. Subcontracted workers’ perceptions of the organizational safety response (OSR) and supervisor safety response (SSR) in their own organization and that of the principal contractor were measured using a safety climate survey administered at a large hospital construction project in Melbourne. One hundred and fourteen construction workers completed the survey, representing nine subcontractors engaged at the project. Two requisite conditions for the existence of group‐level safety climates, i.e. (1) within‐group homogeneity; and (2) between‐group variation were satisfied for perceptions of subcontractors’ OSR and SSR. This supports the contention that subcontractors working in a single construction project exhibit a unique group‐level safety climate. Subcontracted workers also discriminated between group‐level safety climates (i.e. the SSR) in their own and in the principal contractor’s organizations. The results suggest some cross‐level influence. Perceptions of the SSR were positively predicted by perceptions of the OSR in both the principal and subcontractor organizations. Perceptions of the OSR of the principal contractor were also a significant predictor of the perceived OSR and SSR in the subcontractor organizations. Perceptions of the subcontractors’ SSR were a significant predictor of the rate of lost‐time and medical treatment incidents reported by the subcontractor. Although perceptions of the principal contractor’s SSR were not directly related to subcontractors’ injury rates, they were a significant predictor of subcontractors’ SSR, revealing an indirect link. The results suggest that supervisory personnel (e.g. foremen and leading hands) play an important role in shaping safety performance in subcontracted workgroups.     

By‐products formation in catalytic combustion of aromatic compounds over a pt‐based catalyst

By‐products formation in the catalytic combustion of different aromatic compounds has been experimentally investigated. A commercial Pt‐based catalyst, in the shape of a short monolith, has been employed. Toluene, styrene, o‐xylene and cumene have been tested at low concentrations for conversions in the range 5–50%. The results confirm the formation of benzene in the combustion of toluene and styrene, as previously observed by other researchers, but in a very small amount; testing cumene, significant amounts of acetone have been found in the outlet flow. Some hypothesis about the reaction mechanism are put forward.     

Authenticity and its influence on psychological well‐being and contingent self‐esteem of leaders in Singapore construction sector

‘Authentic leadership’ has emerged as an important subject in the management science literature. Although several scholars have presented their viewpoints about authenticity and authentic leadership, there is scarcity of empirical evidence on what leaders can really gain from being authentic. The results of the questionnaire-based survey with 32 leaders suggest that authenticity is significantly correlated with psychological well-being and negatively correlated with contingent self‐esteem. Regression analysis also shows that authenticity successfully predicts psychological well‐being. These findings indicate that authenticity results in healthy psychological functioning of leaders and hence several positive work-related outcomes.     

Rhetoric and reality surrounding water quality issues in a peri‐urban western Sydney community

As the driest inhabited continent, Australia faces pressing issues of water quality and quantity. A recent decade of drought has heightened interest. We surveyed a community on the Hawkesbury–Nepean floodplain, the river that provides most of Sydney’s potable water. The survey targeted respondents’ perceptions of the source of water in local wetlands, causes of water pollution, their willingness to undertake environmental action to improve water quality, and their preferred source of information to inform remedial action. Residents considered that the environmental health of the local waterways was important, and they stated that they were willing to change their habits for environmental improvement. We observed that the first step to environmental stewardship was widespread (although strongest in women) but understanding of issues and the reality of moving from rhetoric to action was less well developed.     

Forecasting nitrogen dioxide concentration in ambient air using artificial Neural‐networks

Artificial Neural‐networks is employed to predict the nitrogen dioxide concentration during November, 1997 to February, 1998 at three sites each representing industrial, commercial and residential activity respectively in Mumbai. The application of the Multilayer Recurrent network with back‐propagation learning algorithm is reported in the prediction at three sites using the meteorological variables at one site. The generalization ability of the model is confirmed by root mean square error and correlation between observed and predicted concentrations. The evaluation of model results shows that the degree of success in forecasting NO₂ concentration is promising.