Modeling human performance in reinforced concrete beam construction

A significant portion of performance failures are due to human error in the construction stage of a structural engineering project. Statistical studies indicate that the construction of in-situ reinforced concrete elements is most prone to error, and that most errors are committed by contractors (either site staff or workmen). Results are reported herein of a survey investigating the error rate and error magnitude of contractor construction errors, and the frequency of engineering inspections and their influence on construction errors. The survey recipients were practicing structural engineers. Probabilistic models have been proposed for the distribution of error rates and error magnitudes, and include within them the influence of inspections. It was found that engineering inspections reduced the initial on-site construction error content by approximately two orders of magnitude. The models provide construction task performance information that can be incorporated into a probabilistic risk analysis of reinforced-concrete construction.