"Need of Delay Analysis in Construction Projects"

Delay analysis in construction claims is essential because any delay must impact the critical path, making it crucial to assess the effect of delays on project timelines.

Construction contracts typically specify that adjustments to critical milestones or scheduled completion dates are only warranted if the delay impacts a critical path activity. This aligns with industry norms, as outlined in the SCL Delay and Disruption Protocol 2nd Edition stating that "an EOT should only be granted to the extent that the Employer Delay is predicted to reduce to below zero the total float on the critical path affected by the Employer Delay to Completion (i.e. if the Employer Delay is predicted to extend the critical path to completion).”

Delay Analysis Methods:

Delay analysis can be performed by a few methods.

1. IMPACTED AS PLANNED ANALYSIS        

The impacted as-planned analysis involves the insertion of delay events into a baseline or as-planned schedule to determine the hypothetical impact of such events. This method involves modifying the baseline or as-planned schedule to include new activities and logic to represent delay events. The difference between the project completion date in the impacted as-planned schedule and the original as-planned schedule quantifies the delay. This methodology is simple and does not require an as-built schedule. However, it is considered a hypothetical model as it does not rely on as-built data.

Steps to perform:

• Identify and quantify impacts to be evaluated
• Select the appropriate baseline or other as-planned schedule. This schedule serves as the “un-impacted schedule” in the analysis
• Create a fragmentary network, or fragnet, representing the impacts being evaluated by the analysis.
• Create the “impacted schedule” by inserting the fragnet into a copy of the un-impacted schedule.
• Identify the critical path of the newly created impacted schedule.
• Compare the project completion date of the un-impacted and impacted schedule to determine the delay caused by the insertion of the fragnet.

The resulting schedule, after inserting the impact event, illustrates the effect of the delay/change event on the project’s completion date.

2. AS-PLANNED VS. AS-BUILT ANALYSIS        

It is a simple technique used to compare the baseline or as-planned schedule to the as-built schedule or a schedule update reflecting progress. This method compares planned start and finish dates with the actual start and finish dates of activities on the as-planned critical and near-critical paths. This identifies delayed starts, extended durations, and late finishes. This method is most effective on simple projects with short durations and one clear critical path that remains consistent throughout the entire project. Its accuracy diminishes as the actual critical path deviates from the planned schedule.

3. Time Slice Windows Analysis        

Time Slice Windows Analysis is an observational, windows-based methodology that focuses on comparing as-planned, updated and as-built project schedules to identify and quantify delays to the critical path of the project.

This methodology is a retrospective analysis that uses the project schedule updates to quantify the slippage to the critical path during a select period of time.

Once all critical path activity delays have been quantified, the origins and causes of each delay are determined. The responsibility for each delay is then apportioned to either the Contractor, Owner, a third party, if appropriate, and to force majeure or other excusable delays defined by the contract.

Steps to perform:

• Select schedule windows;
• Identify the critical path;
• Perform a detailed review of the schedules selected for the analysis;
• Determine the changes made between the schedules selected for the schedule windows;
• Develop variance tables to calculate date and duration variances;
• Research activity impacts and allocate responsibility for delays.

4. TIME IMPACT ANALYSIS         

Time Impact Analysis is a schedule delay analysis technique that adds delays or changes to the schedule which are updated up to the day before the delay occurred.

The Purpose of the Analysis:

• To determine whether the overall completion date of the project is delayed, or remains the same as a result of the delays;
• To demonstrate a Contractor’s entitlement to a time extension;
• To demonstrate a potential schedule acceleration;
• To demonstrate an Owner’s entitlement to receive liquidated damages.

Steps to perform:

• Develop a fragnet to model the delay.
• Obtain the approved schedule which is updated up to the day before the delay occurred.
• Insert the fragnet into the approved schedule update and link to the impacted activities.
• Re-schedule and note a change in the project completion date.
• Determine the amount of project delay.

5. COLLAPSED AS-BUILT / AS-BUILT BUT-FOR ANALYSIS        

Collapsed As-Built Analysis is a retrospective schedule delay analysis technique that determines the earliest date that the project completion date, or a required milestone could have been achieved but-for the owner-caused / contractor-caused delays that occurred during the project.

The Purpose of the Analysis:

• To determine the compensable time extension by taking into account the concurrent delay situation;
• The Collapsed As-Built Analysis that removes contractor-caused delays is used to determine the time period between the actual completion date and the Collapsed As-Built completion date for assessment of liquidated damages by the owner.

Steps to perform:

• Develop a model of the as-built schedule, which is called the As-Built Calculation Schedule.
• Identify the owner-caused or contractor-caused delay.
• Interpret the results of removing delays from the As-Built Calculation Schedule.
• Collapsed As-Built Analysis Illustration