工程專案變更設計進度曲線預測模式之研究

Construction Project Progress Curve Forecasting Model: Change-Orders concerned

湯雁鈞(Yen-Chun Tang)

指導教授 ： 曾惠斌

國立臺灣大學/工學院/土木工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01487

摘要

施工階段進度和成本的管理與控制，常是工程專案管理的主要課題。在實獲值管理中，累積進度曲線可用來描述：與計畫相較，專案目前的進度與成本執行績效狀況，如SPI、SV等。若實際進度曲線低於預定進度曲線，即表示落後，契約中亦常規定進度落後達10%時，得停止估驗計價及其他更嚴格處理。工程專案進行排程時，採用最早開始(ES)與最晚開始(LS)排程結果，進度曲線就會有很大的不同，又於同一計畫可能因規劃者或審查者的不同，而有不同的預定進度曲線；而且目前靜態的、單一點的進度績效，能否表示專案未來進度執行情況，尚需更多討論及驗證；況且依專案過去的執行情況，變更設計後可能的進度和成本趨勢，實務上也希望知道，作為審查修正進度及採取改正行動的參考；因此，在工程專案執行階段作即時的、動態的預測，有其重要性。
回顧過去的研究文獻，大多偏重事後的檢討，期望能回饋給未來同類型的專案進度規劃之參考，有些只有對SPI等參數，做簡單的預測；然對於變更設計後之進度曲線行為尚未提及。本研究希望能考量工程專案多有變更設計的事實，探討調整累積進度曲線之架構，並進行比較文獻中常用來預測進度曲線的數種模式，如三次方程式、Kenley-Wilson formula、Pearl curve、累積常態分配機率等，套用在已完工、有完整預定及實際進度資料、施工階段有變更設計的建築工程新建(重建)工程案例，選擇一合理、誤差較小的模式，作為後續應用之依據。最後以進行中的案例，作為本研究實際應用本模式的說明。
本研究提出的模式，考量大部分工程專案都有變更設計的情況，可應用在三方面：一、提供變更後預定進度曲線未更新情況下之預測模型。二、作為變更後，依專案廠商實際進度執行情形(至少兩期)，預測未來各期甚至完工時的進度，提供實務者採取改正行動等進度管控作為之參考。三、變更後實際進度曲線的滾動式動態預測。

關鍵字

進度管控, 進度預測, 變更設計, 工程專案管理

並列摘要

There are two main topic of construction project management in the construction phase: schedule & cost monitoring and control. In the Earn Value Management System (EVMS), cumulative progress curve could be used to describe: a comparation with plan. We can get the project’s schedule and cost performance by performance indexes or indicators like SPI, CPI, SV, CV. If the earned value is under the planned value, it indicates the project’s progress behind to the present. In many contracts, SPI / SV are regulated to surpass 0.9 / -0.1, otherwise, the contractor may be punish. Howerver, the schedule arrangement will be diverse even if the same project is planned or inspected by different people. The performance indexes mostly are only static, one point, and to-the-present estimators which are poor to forecast the project’s progress in the future. Therefore, the practitioners need to know: according to the contractor’s schedule performance in the recently, how to forecast the schedule trend in the future. Before the project’s schedule monitoring and control fail, they can take corrective actions in time via the believable and rational forecast. It is important to forecast real-time and dynamic in the schedule monitoring, and then to control process for construction project in the construction phase.
In the related works, some review many projects’ progress curve ex post facto, and anticipate to feedback to the new projects’ schedule planning and cash flow management; others only use simple linear regresstion or grey theory to forecast SPI or other indicators. And that, they seldom mention the fact of the construction project usually has change-orders. This study will mention the change-orders fact first, discuss how the progress curve changes when change-orders happened. Then this study will compare the models and methods mostly used for progress curve fitting via case study, such as 3-order polynomial functionl, Kenley-Wilson formula, Pearl curve, and so on. Case study are limited to new building construction project with detail planned value and earned value. This study will then estabilish Construction Project Progress Curve Forecasting Model—concerned about change-orders.
The model has three main applications: (1) How will the planned value change after project has change-orders, (2) Earned value forecasting no matter project has change-orders or not, (3) Schedule trend in the future according to the contractor’s schedule performance in the recently. The practitioners may take corrective actions in time via the model’s results suggestion.

並列關鍵字

schedule monitoring and control, schedule forecasting, change-orders, construction project management

參考文獻

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