| dc.description.abstract | Recent statistical weather information has shown that the increasing frequency and rainfall of heavy and torrential rains correlate with climate change. More typhoons that bring heavy rains can be expected in Taiwan and around the world. Heavy rains bring huge amount of water in rivers, sometimes causing flooding problems and damaging piers of bridges built in the rivers. To minimize the scour and impact of river water against bridge piers, long or no-span bridges are widely adopted. Steel structure bridges are the most popular designs to increase spans between piers and to reduce the number of piers required in the river, and will be the major design in the future for constructing new or renovating existing bridges. Constructing a steel structure bridge consists of several steps; among these steps, pre-assembly of steel components (e.g., steel truss or box girders) is the most critical one for two reasons. First, it has the most elevated tasks in the steel bridge construction process. Second, pre-assembly activity is different in the process because it has both assembly and disassembly tasks, making it more complex than the other steps. Both reasons make pre-assembly activity a step with the highest potential for falling hazards. However, risk assessment of steel structure bridge does not consider pre-assembly activity separately and independently, and engineers (especially junior and inexperienced ones) may misunderstand the criticality of pre-assembly activity. Traditional risk assessment, in addition, uses risk priority number (RPN) but the validity or RPN is disputable. Therefore, this study focuses on steel box girder bridges, one of the commonest steel structure bridges, and proposes a risk assessment approach that applies Fuzzy Delphi Method, failure mode and effect analysis (FMEA) and cause and effect diagram to evaluate the risk of steel box girder pre-assembly activity. The proposed approach is used to analyze three potential hazard types for the pre-assembly activity: falls from elevation, strikes from collapsed objects, and caught in/between equipment or material. The analysis results show risks assessed by the RPN method and the proposed approach respectively are different. Domain experts and practitioners review the results and find the assessment results generated by the proposed approach are meaningful to pre-assembly practices. Therefore, the proposed approach is suitable for risk assessment of pre-assembly activities and assessment results can be a valuable reference for safety engineers and practitioners. | en_US |