Application of human reliability analysis in assessing high-risk activities in Sri Lankan construction sites: a therp-based approach

Abstract

The construction industry is recognised as one of the most hazardous sectors worldwide, with workers exposed to complex and high-risk tasks. Within this context, human error is a leading cause of accidents. To address this issue, the Technique for Human Error Rate Prediction (THERP) method of Human Reliability Analysis (HRA) applies to the construction industry. This study focuses on selected high-risk construction activities, in-cluding tower crane operation, excavation work, scaffolding erection, work at height, and electrical tasks. Semi-structured interviews were conducted with construction safety professionals to identify critical subtasks of con-struction activities, common human errors, and relevant Performance Shaping Factors (PSFs) associated with these activities. Then, nominal human error probabilities were adjusted using a weighted PSF model, and event tree analysis was conducted to evaluate the outcomes of sequential tasks. The study results indicate that tower crane operation, excavation work, and scaffolding erection are the most human error-prone activities. In addi-tion, this study highlights areas where safety management can be strengthened by providing insights to improve human reliability in construction operations in Sri Lanka.