Incorporating rework into construction schedule analysis

Rework has been a primary cause of cost and schedule overruns in large construction projects. While several research efforts have analyzed the causes and effects of rework and provided guidelines to reduce rework, almost no research exists to analyze the impact of rework timing and quantity on schedule delays and to support decisions on cost effective recovery. This research presents a quantitative mechanism for schedule analysis considering rework. The mechanism has three aspects: (1) a new schedule representation of rework magnitude as negative percentage complete for affected activities, documented on the specific date on which the rework is detected; (2) a modified daily-windows delay analysis to apportion project delays among the responsible parties; and (3) an optimization technique for determining the least costly corrective action strategy that recovers project delays. The proposed approach is applied to a case study to demonstrate its ability to consider rework impact, in combination with other progress events by other project parties. This research offers an innovative quantitative approach to consider rework timing and amount in delay analysis and corrective action optimization.

Research highlights
► This study quantifies the impact of rework timing and amount on construction project schedules.
► Daily activity segments are used to record rework amount as negative % complete for affected activities on the rework dates.
► A delay analysis method is used to quantify project delays due to rework and slow / acceleration events by project parties.
► A genetic optimization is then used to determine the least costly corrective action that recovers project delays.
► We conclude that the analysis of rework is crucial to corrective action planning and avoiding project time and cost overruns.