Concurrent Schedule Delay Between Main Contractor and Subcontractor

The situation of concurrent schedule delay is very common in construction, where many "parts" are involved; when " scheduling" is well addressed by the contract, the schedule delay analysis is certainly facil-itated; therefore the contract plays a central role, by addressing specific matters like the ownership of total float and the techniques to be used in "schedule delay analysis" [1]. The problem of concurrent delay is complex and it entails other related issues as "total float management" [2]. In literature various techniques are used perform such as schedule delay analysis, among those the following are generally referred [2, 3, 4]. It's assumes that schedules are CPM (critical path method) based. The specific event or cause of possible delay is described by a single sequence of activities named as "fragnet" (fragmentary net-work).

As-Planned Versus As-Built Comparison Method

The as-planned is the original approved baseline schedule and as-built schedule depicts the actual sequence of the activities as they occurred in the project. Practically the "as built schedule" is the Current schedule update. This methods emphasizes the effects of Owner caused delay.

The Impacted As-Planned Methods (Baseline)

The singles PCOs fragnet are inserted in the original baseline schedule to evaluate and analyze the impacts on critical path(s).

Contemporaneous Period Analyses

This method uses periodic schedule update to determine the effects of PCOs occurring during the course of project. The analysis is undertaken by inserting the "fragnet" on the "current schedule update" relevant to the time-.period at which the PCO occurs [1]. In such cases it might be necessary determine with the Owner which is the schedule update version that can be used, i.e. the version officially approved by contracting officer. It's imperative periodically updating the CPM schedules and getting a formal approval from the Owner. (Note: this method is that one prescribed in the main Contract

The Collapsed As-Built Schedule Method

This method is a variant of the "contemporaneous periods" method; the as-built schedule reflects the actual situation and current update of activities, included the fragnet of PCOs. The analysis is undertaken by "collapsing" the schedule, i.e., extracting the fragnet.

Practical Issues

Using the contemporaneous period analyses or the collapsed as-built schedule method described above, a good approach is to do the following.

* Get approval by...