This study examined the use of individuals control charts to facilitate the productivity improvement of repetitive construction processes. Cycles times for excavation, forming, and reinforcing processes were observed using stratified random sampling during the construction of six residential home foundations. The cycle time information was plotted on control charts followed by an intervention, with the applicable crew members and management, to analyze the charts and propose solutions to any problems identified. Following the intervention, more samples were collected for comparison to the baseline observations collected before the intervention. The mean cycle times were compared before and after the interventions using an independent t-test.
While the results of the all the interventions showed improvement, only one decrease in the mean cycle time during the excavation process proved to be statistically significant. The statistical power of this significant result was only 0.17 due to the fact that the test only had three degrees of freedom. While reliable significant results were not found, this study demonstrates the principles of using control charts in construction to identify process inefficiencies. The results of the method proposed in this study are highly dependent upon the expertise of the personnel involved in the root cause analysis process.
Date of this Version
Building Construction Management
Master of Science
Head of Graduate Program
Advisor 1 or Chair of Committee