Reducing Variability in Concrete Activity Labour Productivity to Improve Labour Performance

Abstract

The management of daily labour productivity variability on site is an important aspect of construction management thinking. The lean technique suggests that reducing variability gives better labour performance. Therefore this paper examines the analysis of labour productivity data of concrete activity from sixty one construction site of single storey buildings in Abuja metropolis. The objective was to determine the relationship between labour productivity variability and labour performance in concrete activity. The data used were collected from sixty one live projects within the study area. The daily method of data collection was adopted in this research. A total of 778 data points were observed for all concrete activities from these sites. The analysis of the performance index that is project waste index (PWI) revealed that some the projects studied were poorly managed because the projects had low productivity rating. While some other projects performed well. The PWI values computed for the project studied ranged from 0.12 to 0.67. It was observed that low outputs were accomplished with high labour inputs. The values for coefficient of variation in labour productivity range from 0.09 to 0.48. These values and the performance indexes calculated for all projects were tested for correlation analysis. The coefficient of correlation for the two variables was found to be 0.601**, which is significant at 0.01 confidence level. The result showed that the variability in daily labour productivity is more highly correlated to project performance than workflow output variability which means that reducing variability in labour productivity appears to have a significant effect on performance. Also the performance gap value for concrete work was found to be 3.62 man hrs/m3. It was recommended that the site managers should determine to get more output with a reduction in input.