Level: Basic
TCM Section(s)
6.4. Forensic Performance Assessment
10.1. Project Performance Assessment
Venue: 2024 AACE International Conference & Expo
Abstract: Critical path method (CPM) schedules are based on the premise that a project has blocks of activities that must be performed in a certain sequence—for example, a foundation must be completed before first-floor framing can be constructed. On many types of projects, the order in which the blocks of work must be performed is mandatory, whereas within a block, the order of work—such as starting at the west or east side of a structure—may be preferential. However, on other types of projects, the blocks of work may be constructed in any order the contractor chooses—for example, on a pipeline project, the segments of the pipeline may be constructed in any order. Projects where the blocks of work may be constructed in any order are often linear or repetitive in nature.
When CPM schedules are used on linear projects, they may provide misleading schedule projections when the sequence of performing the blocks or segments of work changes. CPM schedule analysis is dependent on the order in which blocks of work are completed. As a result, it will give inaccurate results when the blocks of work are performed out of sequence, even though the order is arbitrary, not mandatory. A more useful tool for identifying and demonstrating delay or disruption on linear or repetitive projects is a linear schedule, which allows the easy identification of discrete areas with slow or fast progress and helps identify the impacts causing disruption and delay.
This paper presents examples from actual projects to illustrate how linear schedules can more accurately identify problems on linear projects.
TCM Section(s)
6.4. Forensic Performance Assessment
10.1. Project Performance Assessment
Venue: 2024 AACE International Conference & Expo
Abstract: Critical path method (CPM) schedules are based on the premise that a project has blocks of activities that must be performed in a certain sequence—for example, a foundation must be completed before first-floor framing can be constructed. On many types of projects, the order in which the blocks of work must be performed is mandatory, whereas within a block, the order of work—such as starting at the west or east side of a structure—may be preferential. However, on other types of projects, the blocks of work may be constructed in any order the contractor chooses—for example, on a pipeline project, the segments of the pipeline may be constructed in any order. Projects where the blocks of work may be constructed in any order are often linear or repetitive in nature.
When CPM schedules are used on linear projects, they may provide misleading schedule projections when the sequence of performing the blocks or segments of work changes. CPM schedule analysis is dependent on the order in which blocks of work are completed. As a result, it will give inaccurate results when the blocks of work are performed out of sequence, even though the order is arbitrary, not mandatory. A more useful tool for identifying and demonstrating delay or disruption on linear or repetitive projects is a linear schedule, which allows the easy identification of discrete areas with slow or fast progress and helps identify the impacts causing disruption and delay.
This paper presents examples from actual projects to illustrate how linear schedules can more accurately identify problems on linear projects.