Construction Management & Economics

CHINYIO, EZEKIEL A.; OLOMOLAIYE, PAUL O.

doi: 10.1080/014461999371330pmid: N/A

Our original article (Chinyio et al., 1998a) ‘A needs based methodology for classifying construction clients and selecting contractors’, Construction Management and Economics, 16 (1), 91-98 discussed the empirical classification of construction clients and illustrated a new methodology for selecting contractors. The techniques we adopted have not been applied in a construction scenario before and thus their implementation may face teething difficulties as differences between construction and the disciplines from which the techniques were adopted are ironed out. Due to brevity we did not highlight some of the potential problems their implementation would encounter, as we could not explain everything on the subject matters in one article. Skitmore and Mills (1999) in a comment, Construction Management and Economics, 17 (1), 5-7, highlighted some anticipated difficulties and posed some insightful questions concerning the applicability of our concepts. From an optimistic perspective we have addressed most of the sundry issues raised by Skitmore and Mills wherein ‘Decision Analysis’ was reviewed as a basis for responding to the comments.

PIETROFORTE, ROBERTO; TANGERINI, PIERO

doi: 10.1080/014461999371349pmid: N/A

The characteristics of the Italian construction market and firm operations are reviewed. The analysis focuses on the environments of the late 1980s and early 1990s, during which major scandals and economic recession ended a business paradigm based on closed competition. Discussion builds upon a study of the market positioning of the 50 largest firms during the period under consideration that reflects the state industrial policy over the years. Long term transformations of the market require firms to develop new organizational capabilities and to shift their corporate focus from a production to a service orientation in order to remain competitive.

COX, I. D.; MORRIS, J. P.; ROGERSON, J. H.; JARED, G. E.

doi: 10.1080/014461999371358pmid: N/A

The investigation reported forms part of a wider study into the applicability of design for manufacture (DFM) thinking to the total construction process, and the ways in which this could be implemented. Historical data from change order request procedures were examined for several case studies which were considered to be successful projects. These procedures are intended to capture information about design modifications, and thus can be considered to be analogous to the rework procedures used in manufacturing. It was found that in monetary terms alone, the direct cost of post contract design changes amounts to 5.1-7.6% of the total project cost. Although the case studies used here were a convenience sample, the typical financial opportunity for controlling design changes better is likely to be considerably greater than this. Frequently cited reasons for design changes included: employer has changed his requirements, designer's omission in tender documents and new information on existing site conditions. Little commonality between case studies was found at the work package level. In contrast to manufacturing, the availability and accessibility of data relating to rework is problematic.

WILLIAMS, TERRY

doi: 10.1080/014461999371367pmid: N/A

This paper describes a method for apportioning contingency in a probabilistic network. It distinguishes between two requirements for contingency: for high variance crucial activities, and for high float noncritical activities. This enables a logical two-step apportionment, the first based upon the idea of ‘cruciality’, which has become established as an important indicator of an activity's importance in risk terms, and the second based upon standard ideas about float. A numerical example is given based on data used by previous work, so that a comparison of the methods can be made.

KEIN, ALAN TAN TONG; OFORI, GEORGE; BRIFFETT, CLE

doi: 10.1080/014461999371376pmid: N/A

ISO 14000 is a series of standards defining a formal and structured approach to environmental management. It demonstrates, with assurance, that an organization which complies with current policy and legislation actively addresses environmental issues. Construction activities have a myriad of environmental implications. Hence, construction entities must manage their environmental performance. ISO 14000 represents a possible solution. This study considers the relevance of environmental management to construction organizations. After an overview of the environmental impacts of construction, ISO 14000 and its principles are explored. A field study is reported that was set up to assess the level of commitment of construction enterprises in Singapore to environmental management. Contractors in Singapore are aware of the merits of environmental management, but are not instituting systems towards achieving it. A framework for the development and implementation of an environmental management system (EMS) is proposed.

SHI, JONATHAN JINGSHENG

doi: 10.1080/014461999371385pmid: N/A

An artificial neural network based system (NN earth) is developed for construction practitioners as a simple tool for predicting earthmoving operations, which are modelled by back propagation neural networks with four expected parameters and seven affecting factors. These networks are then trained using the data patterns obtained from simulation because there are insufficient data available from industrial sources. The trained network is then incorporated as the computation engine of NN earth. To engender confidence in the results of neural computation, a validation function is implemented in NN earth to allow the user to apply the engine to historic cases prior to applying it to a new project. An equipment database is also implemented in NN earth to provide default information, such as internal cost rate, fuel cost, and operator's cost. User interfaces are developed to facilitate inputting project information and manipulating the system. The major functions and use of NN earth are illustrated in a sample application. In practice, NN earth can assist the user either in selecting a crew to minimize the unit cost of a project or in predicting the performance of a given crew.

WING, CHAU KWONG

doi: 10.1080/014461999371394pmid: N/A

Plan shape indices are based on the geometry of the plan shape rather than on empirical data, and are problematic as they embrace implicit assumptions that are not tested empirically nor justified theoretically. Empirical research using data in Hong Kong confirms that these plan shape indices are much poorer predictors of unit construction costs than the variables used to construct the indices. This study also develops a method for constructing a plan shape index that is free from the unjustified assumptions implicit in existing plan shape indices; it involves an empirical cost model. Different functional specifications of the cost models are tested. The result rejects the linear model and other special case models such as semi-log and log-linear models. However, the reciprocal model is not rejected. This result suggests that a linear plan shape index can predict the amount of floor area that can be constructed with a fixed sum of money better than the construction cost per floor area.

SWAFFIELD, L. M.; PASQUIRE, C. L.

doi: 10.1080/014461999371402pmid: N/A

This paper describes analysis work undertaken to examine relationships between building function, building form and mechanical and electrical services cost, including the collection of raw data, and the transformation work undertaken to enable analysis. Relationships are identified between building form parameters, e.g. perimeter of external walls, gross floor area, storey heights, percentage of glazing, and the mechanical and electrical services costs for buildings of different functions (commercial, industrial and residential). There are relationships between the costs of the mechanical and electrical services installations and some building form descriptors, but the particular descriptors and the strength of the relationships vary according to the function of the building.