Forensic Schedule Analysis | Adroit Consultants, LLC

Concurrent delays frequently occur in construction projects, especially in complex construction projects in which various contracting parties implement and are responsible for a variety of activities over the project life cycle. Assessing concurrent delays is among the most challenging forensic delay analysis practices because, contractual, legal, and technical considerations add several layers of complexity to cases of concurrent delays.

A project network not only contains project activities but also defines activity dependencies (also known as activity ties or activity relationships). Two or more delayed activities in a project network may be identified to be concurrent when they, partly or wholly, overlap one another. Therefore, a project network is a key tool to identify what activities partly or wholly overlap and what their dependencies are. Courts, boards of contract appeals, and experts, however, are inconsistent in their approach to defining concurrent delays.

Definitions

Experts rely on different references for the definition of concurrent delays. In the United States, one of the technical references that is commonly-cited in delay claims is AACE International Recommended Practice (RP) 10S-90, entitled Cost Engineering Terminology. RP 10S-90, however, does not offer one single definition of concurrent delays. Two of these definitions are provided below (AACE International, 2017, p. 21);

(1) Two or more delays that take place or overlap during the same period, either of which occurring alone would have affected the ultimate completion date.

(2) Concurrent delays occur when there are two or more independent causes of delay during the same time period. The “same” time period from which concurrency is measured, however, is not always literally within the exact period of time. For delays to be considered concurrent, most courts do not require that the period of concurrent delay precisely match. The period of “concurrency” of the delays can be related by circumstances, even though the circumstances may not have occurred during exactly the same time of period.

Another commonly-cited technical reference is AACE International RP 29R-03, entitled forensic schedule analysis. RP 29R-03 identifies that the following tests must be proven to ensure concurrent delays exist (AACE International, 2011):

Two or more unrelated, independent delays exist. One of these delays can a delay arisen from a force majeure event.
None of the delays identified in Step 1 can be a voluntary delay.
Not all delayed activities identified in Step 1 are the responsibility of only one contracting party.
The project completion date would have been delayed in the absence of any of the delays identified in Step 1.
The delayed work has to be substantial (i.e., not easily correctable).

The meaning of concurrent delay is different in the English Law. The following are two excerpts that help illustrate the meaning of concurrent delay under the English law:

True concurrent delay is the occurrence of two or more delay events at the same time, one an Employer Risk Event, the other a Contractor Risk Event, and the effects of which are felt at the same time… In contrast, a more common usage of the term ‘concurrent delay’ concerns the situation where two or more delay events arise at different times, but the effects of them are felt at the same time. In both cases, concurrent delay does not become an issue unless each of an Employer Risk Event and a Contractor Risk Event lead or will lead to Delay to Completion. Hence, for concurrent delay to exist, each of the Employer Risk Event and the Contractor Risk Event must be an effective cause of Delay to Completion (not merely incidental to the Delay to Completion) (The Society of Construction Law, 2017).
Concurrent delay is used to denote a period of project overrun which is caused by two or more effective causes of delay which are of approximately equal causative potency (Marrin, 2012).

Entitlements

Concurrent delays typically entitle contractors to time extension, but not time-related delay damages. In other words, if a contractor is able to demonstrate the presence of concurrent delays, it may be entitled solely to time extension for the net period of the concurrent delay.

It is important to note that in some cases, two or more delays occur concurrently (overlap one another to some extent), all of which are the responsibility of one single contracting party. In that case, the net effect of the concurrent delays have to be taken into account in assessing delays. For instance, if two overlapping 5 day owner-caused delays exist, entirely overlapping each other, the contractor is only entitled to a single 5-day time extension. As another example, if a contractor is found to be responsible for a 10-day delay, 7 of which are concurrent with another contractor-caused delay, the contractor is ultimately responsible for 10 days of delay, not 17 days.

In a similar way, if both an owner and a contractor concurrently contribute to the occurrence of a critical path delay (i.e., a delay that ultimately results in the delay of the project completion date), none of the contracting parties is typically entitled to collecting delay damages from the other party unless delay responsibilities can be apportioned between the parties.

In the event of a concurrent delay, the time impact of a contractor-caused delay on a project’s longest path may be greater in magnitude than the time impact of an owner-caused delay. Under such circumstances, it is sound to expect that the owner is entitled to collect delay damages for the excess impact. Conversely, the time impact of an owner-caused delay on a project’s longest path may exceed the time impact of a contractor-caused delay. Thus, it is critical to perform forensic schedule analysis and closely examine the cases of concurrency to properly allocate responsibilities for delays and specify proper entitlements.

Although definitions of concurrent delays exist in the literature, any assessment of concurrent delays has to start with performing a liability analysis (i.e., entitlement assessment) based on contractual rights and duties of contracting parties. Performing such liability assessments is necessary because the contract may specify how the cases of concurrency are characterized and how they are supposed to be assessed and/or dealt with.

The lack of clear contractual procedures for concurrent delays increases the likelihood of delay-related disputes. As noted above, courts, boards of contract appeals, and experts are inconsistent in their approach to characterizing and assessing concurrent delays. Therefore, it is important that the parties exercise due diligent in preparing unambiguous contract language that facilitates successful resolution of delay-related matters before they result in a conflict.

Moreover, if a party is in a position to negotiate over the provisions of a contract, it is recommended that it negotiates to reach an agreement, prior to signing the contract, on definitions of and procedures for assessing various types of delays including concurrent delays. Such definitions and procedures combined with the use of sound forensic schedule analysis techniques can play key roles in minimizing and/or successful resolution of delay-related disputes.

References:

AACE International. (2011). Recommended Practice No. 29R-03 Forensic Schedule Analysis. Morgantown, WV, USA: AACE International®.

AACE International. (2017). Recommended Practice No. 10S-90 Cost Engineering Terminology. Morgantown, WV, USA: AACE International®.

Marrin, J. (2012). Concurrent Delay Revisited 2. Presented at the Society of Construction Law Meeting, London, England (December 4, 2012).

The Society of Construction Law. (2017). Delay and Disruption Protocol, 2nd edition (DDP2). Retrieved from https://www.scl.org.uk/sites/default/files/SCL_Delay_Protocol_2nd_Edition.pdf

Author: Dr. Amin Terouhid, PE, PMP, PSP | Principal Consultant

Amin Terouhid is a construction claims expert and a Principal Consultant with Adroit Consultants, LLC. He was a recipient of the 2018 AACE Technical Excellence Award.

Note: If you are interested to find out more about the main considerations in assessing concurrent delays, please contact us. Adroit’s consultants have demonstrated their expertise in performing delay analysis and will be able to assist. You may also be interested to read the following articles:

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Project networks play important roles in carrying out construction activities in a timely manner, and they are among the key means of communication that project teams use to coordinate their efforts throughout the process of construction. Project networks are also among the key project artifacts that are used for preparing or investigating time-related claims and for determining entitlements to time extensions and/or delay damages. Therefore, it is important to have a more in-depth knowledge of activity dependencies and their types.

Activity dependencies are among the key characteristics and building blocks of project schedules. A project network not only contains project activities but also defines activity dependencies (also known as activity ties or activity relationships). A variety of activity dependencies exists, and activity relationships are categorized in different ways.

The four main types of activity dependencies include Finish-to-Start (FS), Start-to-Start (SS), Start-to-Finish (SF), and Finish-to-Finish (FF). The following briefly describes these relationship types:

Finish-to-Start (FS): The successor activity cannot start unless the predecessor activity finishes.
Start-to-Start (SS): The successor activity cannot start unless the predecessor activity starts.
Start-to-Finish (SF): The successor activity cannot finish unless the predecessor activity starts.
Finish-to-Finish (FF): The successor activity cannot finish unless the predecessor activity finishes.

Activity dependencies can also be categorized based on the nature of dependencies that exist between project activities. From this perspective, activity dependencies are often categorized into the following two types of dependencies:

Mandatory dependency (also known as hard logic): This relationship represents a dependency that is necessary or inherent in the nature of the work.
Discretionary dependency (also known as soft, preferred, or preferential logic): This type of dependency represents preferential logic that is used to establish a desired sequence of work despite alternative sequences that are acceptable.

To better identify activity dependencies, it is suggested that activity dependencies are categorized as shown in Figure 1.

Figure 1. Activity relationship types

As this figure shows, mandatary relationships can further be broken down into the following three types:

Imposed relationships: Imposed relationships are those relationships that need to be built into a project schedule to satisfy legal, regulatory or contractual requirements. An example includes a contractually-imposed requirement that mandates using a phased approach (where a portion of work has to be implemented after another portion) in completing certain elements of work.
Physical relationships: This relationship represents a dependency that has to be established between two or more activities due to the nature of the work. An example of dependencies that are inherent in the nature of the work is the need to place a foundation first before erecting a column atop the foundation.
Safety relationships: This relationship represents a dependency that has to be established between two or more activities to ensure safety considerations are accounted for in sequencing project activities. An example of a safety relationship is the need to avoid concurrent logic in scheduling two activities that cannot be undertaken simultaneously because of safety concerns (e.g., a crew that cannot work on the second floor of a building because of the ongoing work on the first floor).

Sometimes, project scheduling professionals use scenario-based relationships to define dependencies between project activities. The current article uses the term scenario-based to characterize these relationships because depending on the implementation strategy chosen to execute a project, scenario-based relationships may or may not be used in defining work sequences. Resource relationships are examples of scenario-based relationships. Resource relationships are often added to the project schedule due to resource management concerns (e.g., resource constraints).

For example, if a contractor needs to implement two non-causally-related activities, each of which requiring a crane, the contractor may decide to add a finish-to-start relationship between the two activities if the contractor has only one crane in its possession. In this example, the two activities are not causally related; however, based on the scenario described, the contractor has established a relationship between these two activities to satisfy its resource constraint. If the contractor had two cranes in its possession, defining a dependency between the two activities was unnecessary because as noted above, the activities are presumably not causally linked. Therefore, it is reasonable to recognize the above-referenced activity relationship as a scenario-based relationship because these relationships may or may not be used depending on the implementation scenario or strategy used.

Not all scenario-based relationships are resource relationships; therefore, in Figure 1, scenario-based relationships are broken down into the two main types of resource relationships and others. An example of other scenario based dependencies includes a dependency that is established between two activities based on an assumed what-if scenario to manage a likely change in the project scope of work. This relationship may or may not be required to be established depending on whether the change occurs or not.

The last category of activity relationships is improper relationships that consist of redundant, incorrect logic, and logic loops. Incorrect logic relationships can further be categorized into errors, missing logic, out-of-sequence, and improper use of lags and leads. These relationships will be described in greater depth in a future article.

Planning and scheduling professionals need to make informed decisions in selecting and using the right relationship type. In general, it is suggested that only mandatory relationships are used in developing project schedules unless the use of discretionary or scenario-based relationships is justified. Similarly, the use of preferential relationships may not be appropriate in demonstrating that a schedule follows a reasonable logic. It is recommended that, instead of resource constraints, planning and scheduling professionals use resource leveling techniques to ensure the schedule is not bounded by too many dependencies that could have otherwise been accounted for.

Assessing activity relationships is critical in preparing or investigating time extension requests or delay assessments because a proper delay analysis has to be based on a reasonable schedule. A delay analysis based on a project schedule that contains questionable activity relationships is defective. Project planning and scheduling, forensic scheduling experts, and claim management professionals need to ensure project schedules are free of improper relationships (i.e., redundant, incorrect logic, and logic loops). Otherwise, the schedule will not be reliable or reasonable and it may not serve its purpose.

Author: Dr. Amin Terouhid, PE, PMP, PSP | Principal Consultant

Note:

If you are interested to find out more about the main considerations in developing or evaluating project schedules, please contact us. Adroit’s consultants have demonstrated their expertise in developing, updating, constructability review, and forensic evaluation of project schedules and will be able to assist. You may also be interested to read the following articles:

Adverse effects of schedule deficiencies on claim administration

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