Delay is quite common, especially in construction projects. Delay can be caused by the Client, the Contractor, and the third party or the force majeure that the parties to a contract can’t control. Delay to completion of a construction project could bring significant losses on society as well as the construction project cost. The damage caused by a construction project delay is compensated by the Contractor in principle in the form of ‘liquidated damage’. However, the Contractor shall claim the extension of time or the recovery of financial burden if the Employer is liable for the cause of delay. In fact, a variety of factors contribute to the delay of project completion in complex interdependencies of a number of tasks. Hence determining the contractual responsibility of delay is the most likely source of dispute in construction projects for transportation infrastructure. Methods used for forensic investigation of delay are called as ‘forensic schedule delay analysis methods’. In this article, we will talk about construction schedule delay analysis and types of schedule delays.
Construction Schedule Delay Analysis & Types of Schedule Delays in Construction
Change orders, financial issues, weather conditions, poor design and lack of experience often cause delays on construction projects at any scale. Each cause corresponds to a particular delay. In order to perform construction schedule delay analysis, you need to understand the different types of schedule delays that can occur. Classification of delays helps you to decide what type of analysis to be performed for the circumstance.
Below are different types of schedule delays
Excusable / Non-Excusable Schedule Delays
Excusable delays are caused by events that are unforeseen and not within the contractor’s or the client’s control. On the other hand, non-excusable delays are a result of a delay that was within the control of the contractor or the client.
Examples for Excusable Delays
- General labor strikes
- Natural disasters like floods, storms, and earthquakes.
- Errors and omissions in the designs
- Lack of action by governmental bodies
Examples for Non- Excusable Delays
- Delay in mobilization
- Delay in the submission of documents
- Late performance of subcontractors
- Faulty workmanship
Non-excusable delays can be either compensable or non-compensable. Note that Excusable and Non- Excusable Delays are very important while performing construction schedule delay analysis.
Critical / Non-Critical Delays
A Critical Schedule Delay is one that impacts the project’s completion date. If it does not affect the activities on the critical path, it is a non-critical delay.
Compensable / Non-Compensable Delays
Compensable delays are those where there’s going to be some compensation involved for the delay to the project. Non-compensable delays are caused by something beyond the control of both the client and the contractor.
Concurrent Delays are simultaneous delays caused by the contractor and the client, that affects the project schedule and completion date.
Basic Tools of Schedule Delay Analysis
Critical interests in a project include the estimate of important time for completing it, and identification of the sequence of activities on which delay causes the delay to project completion. A sound estimate of project time requires valid assumptions how the project is carried out. CPM (Critical Path Method) is one of the most commonly used modeling techniques to determine a project’s critical path and calculate the float time and the completion time of the project. In addition, it must prospectively forecast the likely effect of changed circumstances. CPM technique uses the project network analysis technique depending on primarily two variables which are activity durations and relationships . Given the set of activities involved in a construction project with those durations and activity relationships, the CPM uniquely derives the necessary time for completing the project. CPM provides a formal structure systematically describe the project schedule in a way that can simulate the time impact of any change in construction project assumptions.
The as-planned time schedule is supposed to show the Contractor’s true intentions, what activities were planned to be performed, when, in which sequence, etc. as detailed as possible. It is often made by using a software tool. The date of project completion agreed on the contract is calculated based on the as-planned schedule. It is not rare that the analyst may need to correct the baseline schedule before relying on it in any substantive way due to inherent flaws or errors in a contractor’s assumption . If the completion date is determined based on the flawed as-planned program, the project time could be too short which results in delay to completion. Delay due to a flawed as-planned program does not entitle the Contractor to claim extension of time. Thus preparation of reliable as-planned schedule is essential. The as-planned schedule is itself a theoretical model how a particular contractor would like to build a project. To build a valid as-planned schedule, the contractor must identify all relevant information to define the CPM schedule. As a construction project usually involves a number of activities, the validation of an as-planned schedule requires a lot of effort. However, the availability of a reliable as-planned schedule is prerequisite for the integrity of any conclusion.
The as-built schedule should reflect how a contractor actually performed its work. Ideally, an as-built schedule should be prepared and maintained during the course of the work. Otherwise, it cannot be prepared retrospectively unless reasonably detailed schedule is not available. Note that using a construction scheduling software like Primavera P6 helps to make schedule delay analysis.
This blog post “Construction Schedule Delay Analysis” is written by our guest blogger “Ali Osama, Senior Planning Engineer”. We would like to express our thanks to him for his studies.
Linda Maltz is vice president of design and consulting at Cuboca, a project management training and consulting organization specializing in construction management and BIM. She is certified Primavera P6 Trainer.