Assessment of Safety and Health Hazards in High-Rise Building Construction Projects: In the Case of Addis Ababa, Ethiopia

High-rise building construction projects are inherently hazardous due to complex work environments, significant heights, heavy machinery usage, and unpredictable site conditions. This study evaluates key safety and health hazards in high-rise building construction in Addis Ababa, Ethiopia, using two complementary methodologies: the Relative Importance Index (RII) and Fault Tree Analysis (FTA). Data were collected through a structured questionnaire targeting construction professionals to identify potential hazards. The RII was used to rank hazards based on their perceived severity and frequency, while FTA systematically identified root causes and logical relationships leading to critical safety incidents. The findings indicate that falling objects and human error (RII = 0.8072) are the most critical hazards, followed closely by falls from heights (RII = 0.8). Other significant risks include unsafe working conditions (RII = 0.7928), tripping over materials (RII = 0.7874), and falls from scaffolding (RII = 0.7838). The probability of the top event of Major safety and health hazards is 86%, showing substantial risks in safety-critical environments. This emphasizes failures in addressing structural, occupational, environmental, and human factors. Based on these findings, the study recommends implementing a comprehensive, integrated safety approach, appointing dedicated safety officers, enforcing strict maintenance and inspection programs, and monitoring environmental conditions. By integrating RII and FTA, this research provides a comprehensive understanding of the most significant hazards, their root causes, and potential mitigation strategies. The outcomes aim to enhance safety practices, reduce accident rates, and improve overall health and safety outcomes in high-rise construction projects.