An evaluation of production output for in situ concrete work
The overall aim of this thesis is to develop reliable methods of measuring output levels for construction plant and labour, with a view to establishing realistic output rates for concreting operations. This thesis demonstrates that most of the variability in production rates can be quickly explained, leaving relatively constant levels of output f or individual construction operations (i.e. basic operation times). The primary factors in determining output rates were found to be work rate, delays and waiting caused by poor management, and poor motivation. The latter two items accounted f or more than fifty per cent of the available working time on many sites, whereas work rate varied only slightly. This last finding may be surprising, but the results indicated that when work was being done the effort applied appeared fairly constant to the observer. However, the time spent working was largely dependent upon the level of motivation induced through the payment system. Where a combination of good direct supervision and satisfactory financial incentives were present, high levels of motivation were observed, conversely, low motivation occurred on sites where minimum day-work payments were present. Investigations into several construction trades indicate that work study techniques can be modified to meet the requirements of most construction operations, sites and companies, whether the requirements be a complex synthesis of basic operation times or the more simple determination of site efficiency. The key to this portability lies in the isolation of basic operation times via the application of site efficiency factors. In this thesis, primary work study techniques are identified and discussed. The need for specific construction work study techniques is shown to be of paramount importance. The results from over seventy concrete pours are combined and statistically analysed to produce realistic output rates arid current levels of production. Site factors are combined and statistically analysed to produce a relationship between efficiency and level of remuneration. A comparison is drawn between: the production rates achieved on several sites; and the output rates currently being used in the planning and estimating processes.