Production rate measurement for stone-pitched road drainage construction works in Kampala city

Abstract

The production rate of labour affects key planning decisions in the allocation of resources yet little is known about the production rate of stone pitched road drainage works. It is against this background that a field measurement study was carried out mainly to: determine factors that affect production rates for stone-pitched drainage construction works; determine production rates of stone-pitching the different parts of a road drain i.e., side and bottom of road drainage construction works and develop a simulation model to compute the overall production rates for stone-pitched road drainage construction works. Data was collected by using a questionnaire survey to collect data on expert opinions on factors affecting production rates and a measurement sheet filled on site on 35 work segments categorised into six groups based on alignment characteristics. In the Mathematica software, a simulation model on production rates of labour per square meter of the drain was developed. The results show that: level of supervision; motivation factors; tools and equipment on site; availability of materials on site; the number of tasks given to labour; environmental factors; crew configuration; overtime; crew characteristics and length of work sessions are the ten most significant factors affecting production rates. The highest average production rate of 3.17 m2/hour/crew on sidewalls of the drains was achieved by the crew under straight-steep drains whereas the lowest average production rate of 2.35 m2/hour/crew was achieved by the crew under curved-near flat drains. Similarly, the highest average production rate on bottom of drain of 3.42 m2/hour/crew was achieved by the crew under straight-steep drains whereas the lowest average production rate of 3.04 m2/hour/crew was achieved by the crew under curved-near flat drains. Simulated results predicted a 0.347 hours/m2/crew average production rate, with a standard deviation of 0.036 hours/m2/crew, with 0.216hours/m2/crew and 0.613 hours/m2/crew as minimum and maximum production rates respectively. Generally, it was found that the average production rates increased with drain alignment from near flat to gentle to steep drains in both straight and curved drains, at the sides and bottom of the drains. Production rates of crews were highly susceptible to change from time to time due to the change in the prevailing conditions on-site even in the same area (Kampala); the model developed can be utilised to give more informed results. Additionally, further research can be carried out on the same topic in other districts or regions of the country which then could be compared with the findings of this research in the bid to standardise production rates. The findings and model can be employed in project planning, cost estimation, management and control of drainage construction projects