建築工程隱藏性成本之探討-以逆打施工之建築工程為例

Investigation of Hidden Costs for Building Construction – A Case Study of Top-down Construction Building Projects

沈士傑(Shih-chien Shen)

指導教授 ： 姚乃嘉

國立中央大學/工學院/土木工程學系碩士在職專班/碩士(2008年)

摘要

營造工程由於生產運作模式之特殊性質，造成工程施工之成本控制無法如預期。例如在產業競爭下造成承攬價格偏低，工期長導致成本風險高，施工受天候自然環境的影響，協力分包的組合特性使施工品質難以控制，工程施工品質的認定受主觀因素主導等。再加上目前工程型態朝大型化、超高層、深基礎與較高承攬金額之趨勢發展，工程施工之品質、工期、成本、安全之管控難度更高。目前可同時上下部樓層展開施工面之逆打工法，在大型建築工程專案被廣為採用。但也由於施工介面更複雜、施工工期變短、施工動線受限制、施工規劃涉及因素更廣，在工程預算內順利完成工程已成為專案管理之重大挑戰。

本研究以營造工程總承包商的角度，探討採用逆打施工法之建築工程中可能之隱藏性成本。亦即探討此類工程中，工程設計圖說、施工規範與工程標單等相關文件無法直接顯示之工程費用；或已明示於工程標單或圖說之工程項目，但仍有為配合該工項施工所產生額外之相關費用；或其他在施工過程中可能發生之額外費用。本研究以採用逆打施工法之建築工程，針對假設工程、基礎工程與結構體工程等施工階段之工程項目進行討論，並以兩個實際之逆打施工建築工程為案例，分別列出於施工過程產生與隱藏性成本相關之原因與費用，並進行其相關成本產生因素與處置措施的探討。經本研究歸納整理，施工過程中隱藏性成本之產生原因以「施工規劃與工法因素」佔最高，可經由協力廠商之分擔降低此類風險。本研究之成果可供相關人員了解專案之施工與成本的風險，藉以達到成本風險轉移與事前預防的可能，以降低工程專案預期利潤的損失。

關鍵字

逆打施工法 ； 建築工程 ； 工程成本 ； 隱藏性成本

並列摘要

Due to special circumstances of production operation model for building construction, the construction costs usually are not well controlled within budgets as predicted. There are numerous factors affecting the construction costs, such as fierce industrial competition, long construction duration, weather and natural environment, performance of subcontractors, and subjective judgment of construction quality, etc. Also due to the trends for large-scale construction, skyscrapers, deep-foundation projects with huge construction budgets, it becomes much more difficult to control quality, progress, cost, and safety of the projects. Building construction projects adopt the popular top-down construction method are often seen examples. Because of the complexity of construction interface, shorter duration, and limitations at construction site, completing such project within budget has become a serious challenge to project managers.

From the perspective of general contractor of the building project, this study aims to investigate the possible construction expenses that are not shown on the construction diagrams, specifications, or tender documents during construction of the project which adopt top-down construction method. This study examines such building project to investigate causes and relevant expenses of hidden costs during the process of construction in temporary facility, foundation, and structural system. Factors of the relevant costs and measures to handle the situation are also investigated. Two actual construction projects were examined to show all possible hidden costs. It was found that “construction planning and method” was one of the major causes of hidden costs and the rick could be reduced by transferring to subcontractors. The results of this research can serve as useful references to personnel who are involved in such construction project to achieve a successful project management.

並列關鍵字

Top-down Method. ； Hidden Costs ； Construction Cost ； Building Construction

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