Model for Predicting Impact of Loss due to Task Demand Exceeded Capability of Construction Workers

Abstract

Most construction safety models focus on finding causal factors, suggesting the protective methods, ways to handle with these causes and also issuing rules of safety to enforce unsafe acts and unsafe conditions. The limitation of construction accident causation models is that they cannot explain the worker behavior, which is under constant adjustment according to task demand and capability. Workers' behavior tends to migrate closer to the boundary of the functionally acceptable performance due to two primary pressures: the management pressure for increased efficiency, and the tendency for least effort, which leads worker to risk condition at almost all times. This research framework proposed the construction safety equilibrium model between task demand and capability of workers. The model can be used to predict the impact of accident when workers migrate into the risk condition. Factors that influence the task demand and capability were investigated by the Delphi method; the weight and grouped factors were determined by Analytic Hierarchical Process via interviewing the high-rise construction safety experts. The completed model was validated by 100 actual accident cases. The proposed model is able to 1) analyze the task demand level and capability level of the workers during the time that accident occurred, and 2) determine the impact level of accident from the difference between the task demand level and the capability level.