運用BIM數量計算以利工程進度S-curve之建立

Abstract

工程進度之管控是影響營建工程專案成功的一個重要關鍵，而工程進度經常以成本累積曲線(亦即S型曲線或S-curve)做為管控的依據。製作S-curve進度曲線時，於每單位時間內(例如每日或每月)，必須計算各進度(施工)作業(scheduling activities或construction activities)預定(或實際)執行之施工材料數量，再乘以材料之單價，求得其預定或實際成本。此計算過程中，必須確認各進度作業所對應施工材料的成本項目(cost items)，且因為此對應關係可能是一對一、多對一、或多對多的關係，致使計算各進度作業之執行成本是件繁瑣的工作，而由於此工作一般乃透過人工判斷，耗時且錯誤機率極高。 近年來，以三維(3D)為基礎架構之建築資訊模型(Building Information Modeling, BIM)，其數量計算能力已逐漸展現其效益，本計畫擬運用BIM數量計算的資訊化能力，快速且降低錯誤地，建立一套繪製S-curve預定(與實際)進度曲線之模式，以有效管控工程進度。研究主要重點包括：(1)於Revit建立包含成本項目之BIM模型、(2)於Autodesk QTO(Quantity Take-Offs)軟體中進行數量計算、(3)於經費電腦估算系統(PCCES)軟體中擷取對應成本項目之單價、(4)彙整至Excel計算各進度作業之成本並繪製S-curve。本研究擬透過北部某一科技設施工程實例，驗證所提模式之可行性。研究成果預計貢獻於專案工程之進度管控與擴展BIM之運用等領域。

A cost cumulative curve (called S-curve) is often used as a basis for effective schedule control which is a key to the success of construction projects. In establishing a planned (or actual) S-curve for a construction project, first, one needs to determine the quantities of the planned (or actual) construction materials in each time unit (such as day or month) for each scheduling or construction activity. Then, by searching for the unit prices of cost items for the corresponding construction materials, the costs of activities can be calculated by multiplying the quantity and unit price. However, this labor-intensive computation process is highly time-consuming and error-prone because the relationships between scheduling activities and cost items could be 1-to-1, many-to-1 or many-to-many. Currently, the 3D-based building information modeling (BIM) technique has been recognized in its effective ability in quantity take-offs. This research thus proposes to apply the BIM quantity take-offs to facilitate the establishment of the planned (or actual) S-curve for a construction project. The proposed model will include four main steps: (1) incorporating the data of cost items into Autodesk Revit model, (2) using Autodesk QTO to conduct the quantity take-offs, (3) capturing unit prices from the PCCES (Public construction Commission Estimation System), and (4) converting to Excel to calculate the activity costs and build S-curve. This study will test the proposed model via a high-tech facility building in northern Taiwan. The research is expected to contribute to practitioners in the domains of project schedule control and BIM uses.