Abstract: For the sake of preventing accidents in operation of high risk construction, a quantitatively improved JHA method was introduced into the risk analysis of high-risk operation in construction. Firstly, high-risk operations were identified by the LEC evaluation method and a hazard identification model based on "2-4" model was established. Then, the risk levels of operation steps were evaluated and the key steps were determined by calculating the compound risk on the basis of the weight of each operation step. Finally, the risk levels of high-risk operations were determined by calculating the weighted risks. Taking the scaffolding erection in a building's construction as an example, the quantitative improved JHA was carried out. The results show that key steps are the equipment of operators' protective equipments and work at height (scaffolding erection), that the key steps determined by compound risk degree are the focus of safety management, and that the risk levels of high-risk operations determined by weighted risk degree are consistent with the actual situation.

Key words: construction, job hazard analysis(JHA), high-risk operations, hazard identification, risk analysis