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(PS-1691) Calculating the As-Built Critical Path

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Primary Author: Mr. Andrew Avalon PE PSP

Audience Focus: Intermediate
Application Type: Application
Venue: 2014 AACE International Annual Meeting, New Orleans, LA, USA

Abstract: The as-built critical path of a project schedule can be determined by developing As-Built Calculation Schedules for each relevant schedule analysis period. An As-Built Calculation Schedule removes verified actual dates from the schedule and revises the activity and lag durations to be equal to the actual durations. The creation of the As-Built Calculation Schedule enables the CPM scheduling software to then calculate the as-built critical path. To properly create an As-Built Calculation Schedule, it is necessary to determine the driving predecessor relationships in the as-built schedule when there are multiple predecessors to an activity. If a predecessor is not driving, the actual lag duration should be reduced to the originally planned lag value to create float in the As-Built Calculation Schedule. If the determination of driving predecessor relationships is not performed, all activities in the As-Built Calculation Schedule would have zero total float and would be equally critical. This paper presents procedures to ensure that the as-built driving lag values are determined objectively to avoid inconsistent or subjective assessments in calculating the as-built critical path.