| 摘要: | 從近年的統計分析，已能肯定氣候暖化與豪大雨的增加有關，所以未來帶有龐大強降雨的颱風，在台灣或世界各地發生的機會將會大增。過去橋梁因跨距小，橋墩多有落墩於河道上，易造成橋梁被河水、漂流木沖擊。台灣地形十分倚靠橋梁，為了讓橋梁使用更加安全，在設計上應改為長跨距或無跨距橋梁的設計，鋼構材質的橋梁可使跨距加大、減少落墩數量，避免橋墩被沖刷的風險，是未來橋梁重建的趨勢。在鋼構橋梁的施工程序中，鋼構件假組立(預裝)作業是最重要的一項步驟，除了因為鋼構件假組立(預裝)為鋼構製程中高架作業最為頻繁之步驟外，假組立(預裝)作業方式因為多了拆除作業使其比其他鋼構製程冷作加工、電銲組立等階段更為複雜。 此二原因讓鋼構件的假組立(預裝)作業具有較其他步驟為高的職災風險，但實務上假組立(預裝)的風險評估與分析並未獨立出來，使其易被視為與其他作業步驟具有相似之風險，特別是對工作經驗較欠缺之工程師而言；再者，以往風險評估多使用風險優先數(Risk Priority Numbers)來計算，但風險優先數仍有其爭議之處。因此本研究提出以模糊德菲法(Fuzzy Delphi Method)來計算風險權重值，以失效模式與效應分析(Failure Mode and Effects Analysis FMEA)為架構搭配特性要因圖(Cause & Effect Diagram)，針對鋼結構橋中最常見的鋼箱樑橋之箱樑假組立(預裝)製程實施風險評估，以建立一製程風險分析模式。根據勞動部勞工保險局全球資訊網揭示之職業災害給付資料所示，製造業、營造業各重大職災類型中，以墜落所造成之影響最大，加以假組立(預裝)作業具有許多高處作業，因此本研究以「墜落」作為主要分析標的，另同時將勞工保險局職業災害給付資料統計中常見之「倒(崩)塌」及「捲夾」失效模式納入分析標的。研究結果發現採取模糊德菲法與傳統風險優先數法之風險差異較大者依序為「倒(崩)塌」、「墜落」、「捲夾」;其說明模糊德菲法所計算之風險權重值提得以提供風險管理者另一具參考價值之風險評估答案。;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. |
