A construction time information system for the building industry

The thesis considers the possibility of establishing a computerised construction time information system for time planning of a building at early design from minimal information. The literature reveals no consensus in description or classification of factors that influence construction times, nor models that demonstrate the organisation of project information for time evaluation and planning. The research objectives are: to prioritise factors that influence construction times, to represent such factors in an information system and to test the system as a basis for predicting and planning construction times from minimal information. Three distinct research methods are used: the descriptive survey method for data gathering, the analytical method for investigating predictive relationships; and the experimental method for testing the system. A preliminary survey showed that time influencing factors can be prioritised and confirmed a commonality of programming procedure and activity identification. A second survey yielded data for sixty-two variables on thirty-six private commercial buildings. Multiple linear regression analysis shows that the durations of activity groups: Substructure, Superstructure, Cladding, Finishes, Services and their sequential start-start lag times can be predicted from twelve variables: gross floor area, area of ground floor, approximate excavated volume, building height, number of storeys, function, cladding type, presence of atrium, building location, intensity of services and site accessibility. These results are incorporated into a proposed information system with the dual role of data retrieval and storage, and time planning of proposed projects from minimal information. An experiment involving nine planners and three office projects shows that the model predictions are generally consistent with the planners' estimates and with the estimates of the projects' constructors. The model fulfils the research objectives in providing an effective, simplified approach to organising project information for early time planning.