2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Dr. Tarek Hegazy, University of Waterloo
Construction projects usually operate in dynamic multi-party constrained environments that frequently cause schedule delays, cost overruns, and disputes among parties. To mitigate construction disputes and fairly apportion delay responsibilities among project parties, forensic schedule analysis becomes necessary. Among the available schedule analysis techniques, two techniques have been widely used by researchers and practitioners to assess delay responsibilities: But-For; and Windows Analysis. Both techniques are considered acceptable tools by courts and arbitration boards. However, several improvements have been introduced to both techniques in literature and in the various forensic analysis standards, each with different assumptions. The different methods vary in their use of a single versus multiple windows of analysis. More importantly, the adoption of either the literal or functional theory, for the concurrent delays, may affect the analysis results. The literal one is a strict perspective that requires true concurrency so that the delay-causing events are happening simultaneously, while the functional theory represents the practical and more flexible perspective that consider project delays concurrent even if the causing events occur in different, but close, time periods. Based on their varying assumptions, the delay analysis results and limitations vary among the various methods in the recommended forensic analysis guides. For example, due to the single window implementation of But-For analysis, it is unable to account for the critical path fluctuations within the window or identify the true concurrency. Windows analysis, on the other hand, produces different results when using different window sizes. In windows analysis, however, calculation errors often occur when the progress events of a single day lead to multiple days of project delays. The allocation of responsibility in this case can be complex, particularly when acceleration by one party is involved. The disparity among the methods and the analysis standards creates confusion and less trust in delay analysis techniques, contributing to escalating disputes and difficulty in assessing time extensions and cost compensations. This research aims at clarifying the misconceptions in the use of the various delay analysis methods, compares among the various forensic analysis standards, and examines the impact of the various assumptions on the analysis results. Accordingly, the paper provides guidelines towards accurate and equitable forensic analysis for both researchers and practitioners.