A critical investigation of factors influencing buildability and productivity

The research reflected in this thesis is concerned with the investigation of "buildability" or, the effect that the design aspect has upon the construction process. It is intended to promote a greater understanding of buildability both in terms of its theoretical concept and practical application. The programme of research is a natural progression to a series of productivity studies carried out by the Construction Research and Co-ordination Division of the Scottish Development Department, the Scottish Division of the National Building Agency and the Building Research Establishment. These studies, which began in the early 1970s, have investigated ways of reducing the time taken to build traditionally-designed houses by rationalising the process of building and by improving the communication of the various specialised disciplines involved. Since these housebuilding studies, attention has been directed towards applying the principles established in other building types. Of particular interest are those building types for which a continuous building programme is assured. Such application allows the possibility of longer-term benefits accruing through continual refinement of the design. In 1979, the Scottish Development Department was commissioned by Lothian Health Board to design a phased health centre development at Wester Hailes, Edinburgh. This project constitutes the practical, case study for this investigation into buildability, with the primary objective being to incorporate the findings from earlier analytical studies investigating housebuilding productivity into a live project of a different nature Its intention also, is to develop awareness beyond the narrow aspect of productivity towards a broader attitude of identifying and understanding those factors which significantly influence the achievement of better buildability and increased productivity. To evaluate the success of this application, the construction phase was monitored using modified activity sampling techniques. Although analysis reveals findings which may be unique to the Health Centre, certain characteristics emerge to question the general principles of buildability suggested in previous empirical studies. The main conclusions may be summarised as follows: (1) There is little evidence to support the theory that design rationalisation is a major influence upon increasing productivity and achieving better buildability in relation to traditional design. (2) Empirical studies conducted by the SDD, BRE and NBA have suggested that it is possible to transfer any potential influence towards increasing productivity direct from housing to other forms of construction. There is little evidence that this was the case with the present project. (3) In empirical studies, too great an emphasis has been placed upon collecting and analysing purely quantitative data to support manhour expenditure rather than obtaining evidence to explain the factors which govern that expenditure. (4) Managerial aspects are identified as maintaining the greatest influence for increasing productivity and achieving better buildability. (5) Managerial capability can overcome inadequate design, but a well-rationalised design will not overcome inadequate management. (6) Ad-hoc managerial procedures are equally as important as planned management in achieving project success when the construction sequence becomes divergent from the programme. (7) With management representing a key factor in achieving better buildability and increased productivity, future contractual procedures need to be developed which encourage managerial capability to be used to its fullest extent throughout the building process.