Abstract Assessing schedule delay's impact on total project duration to distribute delay liability remains a controversy. None of existing delay analysis methods is perfect because including an element of assumptions, subjective assessment and theoretical projection. Windows-based delay analysis methods are excellent in identifying and measuring construction schedule delays. Based on a previous study identifying potential problems in available windows-based delay analysis methods, this study proposes an innovative windows-based delay analysis method, called the effect-based delay analysis method (the EDAM method). The EDAM method performs delay analysis using extracted windows and determines delay impacts by considering the effects of delays on the critical path(s). According to its application to hypothetical cases and comparisons with other methods, the EDAM method is efficient in delay analysis and effective in solving concurrent delays and determining schedule shortened. The proposed EDAM method is a good alternative for schedule delay analysis for construction projects. © 2011 Elsevier Ltd. and IPMA. All rights reserved. Keywords: Delay analysis; Claim; Schedule analysis; Construction project
1. Introduction Construction projects generally have highly complicated situations during execution, involve many project stakeholders and interfaces, and are influenced by many external factors. Therefore, schedule delays in construction projects are common and affect total project duration in unpredictable ways. Delay information and evidence are usually recorded and represented in different records, documents and schedules during the construction phase. Selecting a suitable delay analysis method and analyzing delay information accurately are essential tasks in any delayed construction project. Current delay analysis methods analyze delay liabilities based on delay information and evidence. Various analysis methods have been developed, such as global impact, as-planned, impacted as-planned, net
⁎ Corresponding author. Tel.: +886 3 4227151x34040; fax: +886 3 4257092. E-mail address: firstname.lastname@example.org (J.-B. Yang).
impact, time impact, collapsing, isolated delay type, snapshot, window analysis and isolated collapsed but-for (Bordoli and Baldwin, 1998; Gothand, 2003; Hegazy and Zhang, 2005; Kim et al., 2005; Mbabazi et al., 2005; Ng et al., 2004; Yang and Yin, 2009; Zack, 2001). Farrow (2007) had clearly claimed that none of the delay analysis methodologies is perfect because they all include an element of assumptions, subjective assessment, and theoretical projection. Generally, a delay analysis method attempts to discover delay information derived from as-planned and as-built schedules, those are the bases for resolving delay disputes and claims. However, existing delay analysis methods still have the following shortcomings: (1) concurrent delays cannot be recognized or calculated by some of existing methods; (2) the critical path method cannot be executed in analysis and critical path changes cannot be considered; (3) the relative cost of float consumption is not considered; (4) analysis is not contemporaneous with delay timing; and (5) most methods focus only on the delayed activities, and ignoring the effects of time-shortened activities on total project duration (Arditi and Pattanakitchamroon,
0263-7863/$ - see front matter © 2011 Elsevier Ltd. and IPMA. All rights reserved. doi:10.1016/j.ijproman.2011.06.003
J.-B. Yang, C.-K. Kao / International Journal of Project Management 30 (2012) 385–397
2006; Bordoli and Baldwin, 1998; Gothand, 2003;...