Abstract: For the sake of promoting the safety management of tower cranes in a complex sociotechnical system,the safety of the tower crane was studied by using the system thinking method.Firstly,characteristics of tower crane system were analyzed to understand the components of tower crane safety system.Second,based on RASMUSSEN risk management theory,a hierarchy system of tower crane safety system was established,which contains 5 levels,including regulatory bodies,tower crane stakeholders,construction site management,on-site staffs,environment and equipment.Then,systematic identification of 56 factors influencing tower crane safety was carried out through literature review,accident analysis and expert interviews.A generalized generic Accimap model of tower crane safety was built by using Accimap modeling technique.Finally,the system mechanism of tower crane safety is further analyzed in view of complex sociotechnical system.Results show that tower crane safety results from coupling of multi-level and multi-dimensional factors,and it is affected by feedback between layers,migration phenomena and dynamic environment,and that tower crane safety management should follow the vertical integration idea,pay attention to the factor interaction path,and take systemic interventions and control measures.

Key words: tower crane safety, complex sociotechnical system, risk management framework, system mechanism, Accimap model