Abstract—Delay is a widely crucial problem of the construction project especially in developing countries. The creditability and accuracy of calculation of project’s delays and its impacts is an important part of the construction projects that is necessary for project parties to minimize and prevent project derogation from occurred delay events. In the past two decades, the several Delay Analysis Methodologies (DAMs) have been developed, but there is no successful case using those models in real construction. Most of them are having considerable drawbacks such as flexibility limitations for using in various projects, lacking of reliability and requirement of too much work. They are not acceptable to use in real projects in Thailand. The aim of this research is to study in depth of the existing Delay Analysis Methodologies used in Thailand construction projects and find out ways for their improvement. 8 DAMs named Net Impact Analysis, Global Method, S-Curve, Time Impact Analysis, Window Analysis, Collapsed As-built, Impacted As-planned and As-planned vs As-built were selected because of the past numerous studies have debated them as the most popular techniques used for delay assessment in construction projects. The authors presented them to 3 groups of respondents from owners, contractors and consultant firms for their feedbacks in the views of 6 parameters; 1) Level of awareness 2) Frequency of use 3) Information requirement 4) Complexity 5) Associated costs and 6) Success rate. Expert’s interviews were also conducted for result validation and finding ways for existing DAM’s improvement. This research has found that S-Curve, Time Impact Analysis and Impacted As-planned techniques are the most suitable for Thailand construction industry and there are some improving factors that need to be developed by new researches with engineering software or computing models for more practical implication in real construction projects.

Keywords—construction delays, delay analysis techniques, delay effects, existing delay analysis models

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