Activity-based safety risk quantification for concrete formwork construction

Most of safety risk research focuses on high-severity safety risks for large-scale construction processes. Such studies help firms identify the highest risk processes so they may be targeted for improvement. However, few studies quantify safety risk at the activity level or include low-severity, high-frequency risks that some literatures suggest contribute to a large proportion of total risk. This paper presents research that involved the holistic quantification of risks for the activities associated with the construction of concrete formwork. Three major research efforts are discussed: (1) identification of activities required to construct concrete formwork; (2) selection of an appropriate all-inclusive and mutually exclusive risk classification system; and (3) the quantification of the average frequency and severity levels for each risk classification associated with each activity. To identify formwork construction activities, 256 worker-hours of observation were conducted and the resulting activity descriptions were reviewed and validated by industry professionals. Risk classifications appropriate for this study were created by aggregating relevant literature. Finally, the Delphi method was implemented to individually quantify average frequency and severity using scales that define the entire spectrum of possible values. In total, 130 frequency ratings and 130 severity ratings were obtained over three rounds of Delphi surveys. Results indicate that there are 13 major activities required to construct concrete formwork and the highest risk activities are applying form oil, lifting and lowering form components, and accepting materials from a crane. The data presented in this paper can be used to target specific high-risk formwork construction activities for improvement.