Construction Manager Review of Contractor Submitted Schedules

INTRODUCTION
The philosophy and the level of detail used in the development of a schedule depend very much on whether it is a pre-construction schedule prepared by the construction manager for bid purposes or whether it is a post-award schedule prepared by the contractor to meet a contract-stipulated project duration. The schedule developed by the construction manager in the pre-bid stage is generally geared to establishing a reasonable project duration for inclusion in the bid documents. In such a schedule, deliveries of long lead equipment, regulatory agency review/approval times, owner imposed constraints, weather constraints, and availability of resources play a key role rather than any resource constraints that may be specific to a contractor. On the other hand, the contractor developed schedules are geared to minimizing the negative cash flow and optimizing the deployment of available resources (for self-performed and subcontractor work) to complete the job within the time constraints specified in the contract. The incentive/disincentive clauses stipulated in the contract also play a significant role in the contractor-developed schedule. Most contracts specify that the successful contractor submit the baseline schedule within a given time period (generally 30 days from the notice of award) for review by the construction manager/owner. After the review and approval process, the contractor revises and resubmits the schedule as the baseline schedule for the project. The baseline schedule is an important project document in that it:

o reflects the contractor’s strategy and timetable in the implementation of the project within the specified contract duration,
o is used for all progress updates and to establish all schedule variances,
o is used to develop a recovery schedule to recoup any lost time and to bring the project back on schedule, and
o provides a basis for analysis and resolution of delay claims.

Following is a suggested checklist for use in the review of contractor-generated baseline schedules. In developing this check list it is assumed that the contractor has also furnished a back-up copy of the schedule data on a diskette (using Primavera or similar software) in addition to the hard copies of schedule reports and graphics.

SCHEDULE REVIEW GUIDELINES

I. Global Review

This is a quick check to establish whether the schedule submitted by the contractor conforms with the overall time requirements specified in the contract:

1. Notice to proceed (N.T.P.) date
   
2. Project start date
   
3. Project duration in terms of completion date or number of calendar days specified from the N.T.P. date
   
4. Intermediate milestone completion dates, interface milestone dates and/or beneficial occupancy dates
   
5. Owner-imposed date constraints, e.g. access to job site, shutdown periods for maintenance, restricted work periods due to other contractor’s activities, holiday and winter work constraints
   
6. Scheduling method to be used, e.g. Arrow Diagram Method (ADM), Precedence Diagram Method (PDM)
   
7. Schedule documents submittal, e.g. schedule reports sorted by Early Start, Total Float, 60-day Look-Ahead, Activity ID, Area, and schedule graphics such as Bar Charts, Pure Logic Diagrams, Time Scale Networks
   
8. Cost loading of activities (not all contracts specify cost-loaded schedules)
   

II. Scheduling Mechanics Review

Scheduling programs such as Primavera can generate a diagnostic report which can be very useful. In addition to providing scheduling statistics this report also includes (see Table I):

1. Number of activities started and completed. Because the schedule data date should be the same as the project start date, baseline schedules should not show any progress or actual start dates.
   
2. Scheduled start and completion dates. These dates can be verified against the project start and completion dates specified in the contract.
   
3. Listing of open ends. This is a list of all activities not having predecessors and successors. Ideally, in a properly developed network only the starting activity has no predecessor and the ending activity has no successor. Networks with many open ends will result in an erroneous critical path and unrealistically high float values.
   
4. Listing of date constraints. This is a list of all activities with imposed date constraints. While date constraints can be imposed on specific activities (e.g. procurement items, interface work), excessive usage of date constraints in lieu of network ties may lead to inaccurate schedule computations.
   
5. Listing of milestones. This is a list of activities identified in the schedule as start or finish milestones. This list can be used to check conformance with the milestones specified in the contract .

III. Schedule Analysis and Review

1. Activity durations. Check the reasonableness of the activity durations with regard to the quantities of work involved. In addition, some specifications may limit activity durations to no more than 15 working days except for long-lead procurement activities.
   
2. Schedule logic. Check whether all the activities are networked using the diagnostic check outlined in item I, Global Review. In addition, examine the validity of the relationships in terms of normal construction practices. For example, too many activities with a number of start to start relationships with time lags (i.e. excessive number of concurrent activities) can create "stacking" of trades. This can lead lead to problems associated with resources, construction safety and jurisdictional issues.
   
3. Project calendar. Check the correctness of the project calendar in terms of the work day/work-week calendar (5-day, 6-day, 7-day/week) along with non-work periods (weekends and holidays) and shutdown periods. Attention should also be paid to schedules with multiple calendars where different activity durations are expressed in work days and calendar days.
   
4. Critical path. Since the critical path determines the project duration, it is vital that the critical activities, durations, and the associated logic is valid and reasonable. Schedules with multiple critical paths and/or too many critical activities indicate a very tight schedule. Such a schedule needs a careful examination for possible manipulation of the critical path that could set a stage for future delay claims. In addition, it is necessary to examine activity paths which are near critical and subcritical. These activities have very little float (usually, in the range of 1 to 10 days) and could become critical even when minor changes in the field conditions occur. The Construction Manager, as an agent of the owner, should also examine specifically the activities for which the owner and/or his representatives are responsible and ensure that adequate time is allowed for accomplishing these activities. Activities which fall under this category are: construction permits, shop drawing review and approval procedures, change order processing, traffic rerouting plan approvals, and utility relocation work. It is obvious that any delays caused in the completion of these activities will come under owner-caused delays and result in costly time extensions.
   
5. Float analysis. It is also important to identify activities with excessive total floats. These activities are generally associated with open ends, date constraints and inaccurate logic. It is necessary to correct the logic and bring the float times to realistic levels so that the available resources can be more effectively used.
   
6. Long-lead procurement activities. Most procurement items (such as structural steel, process equipment) will have to go through the shop drawing review and approval cycle before fabrication can begin. The shop drawing submittal and review turnaround times shown in the schedule should be consistent with the contract documents. Check for schedule conflicts in the coordination of the interface shop drawing review process between two vendors on early delivery items. For example, anchor bolt pattern details and delivery of embedments may be required early for an equipment support foundation even though the equipment itself is not installed until a later stage. The delivery schedules shown for any owner-furnished equipment should also be consistent with the schedule data furnished in the contract documents. In situations where equipment installation contractors and vendors are separate, it is important to check the equipment delivery schedules against the timely availability of unloading equipment/crews, and covered/secured storage areas on the job site.
   
7. Weather delays. Examine the nature of work performed (e.g. concrete, earthwork) and productivity levels achieved during winter months and/or periods of adverse weather. Check for conformance with the contract documents because some public agencies like the Illinois Department of Transportation (IDOT) publish their own schedule of anticipated work days per month.
   

CONCLUSIONS
The checklist developed above, while by no means exhaustive, has been used by the author in the review of schedules on several construction projects during his former association with a major consulting company. Inputs are welcome so that the material presented can be further streamlined.

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