具體的BIM目標將大幅改善工程專案規劃的水準與溝通效率,可以大幅提升營建生產力。本研究以丙級營造廠自主導入BIM做中小型公共工程營建管理之實際案例為探討範圍。本研究案例工程專案營造廠導入BIM的成本效益如下:專案導入BIM的投資報酬率=296%,專案導入BIM的效益占工程契約金額=1.73%,導入BIM所發現事件的重置成本占工程契約金額=17.33%。導入BIM執行計畫書以外的BIM項目:景觀框架模型、機電設備元件、彩現動畫展示等應用,額外增加的費用對專案效益不大甚至為零,其邊際報酬率為:-92.8%。專案此時的BIM邊際報酬率為負,證明BIM效用亦符合邊際效用遞減法則。營造廠可於工程專案初始,規劃施工階段參考本研究進行施工風險評估,以風險矩陣列出本身易發生失誤或缺失的高風險工項,據以擬定BIM執行計畫,決定模型元件細緻度所需之LOD(LOD 100、LOD 200、LOD 300、LOD 400),專業廠商之施工模型主要構件之元件細緻度約LOD 400,次要構件之元件細緻度約LOD 100- LOD 300,可最佳化節約BIM建模成本,以期達到施工階段導入BIM應用之效益最大化。
With these specific BIM goals, contractors are able to improve the level of project planning and communication, greatly improving construction productivity. In this case study, the cost effectiveness of integrating BIM into the public works project is as follows: Return on investment of BIM integration was 296%. Benefits of BIM integration accounted for 1.73% of the project contracted total. Resolution of conflicts unveiled through the integration of BIM accounted for17.33% of the project contracted total. BIM costs resulting from BIM execution resulted in a negative marginal utility of-92.8%. The negative marginal utility of this instance demonstrates BIM utility is subject to the law of diminishing marginal utility. Utilizing this research and risk matrices, contractors can identify sources of potential errors at the start of the project and determine the LOD requirements. To maximizing the cost effectiveness of BIM integration during the construction phase: Primary components are simulated at a LOD of 400. Secondary components are simulated at a LOD of 100 ~ 300 is the most effective in terms of BIM simulation costs.