Comparative performance evaluation of the traditional design-Bid-Build (Dbb) and Design-Build (Db) procurement methods in Ghana

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The Traditional design-bid-build (DBB) and the emerging design-build (DB) are alternative procurement methods currently in use in the Ghanaian construction industry. The client and stakeholders in the construction industry continue to complain about the industry’s inability to deliver projects within the scheduled project duration, budgeted project cost and acceptable project quality. Construction clients in Ghana, like clients in the rest of the world, are looking for the best procurement method that can meet their needs. This desire calls for an assessment and comparison of the performance of the existing procurement methods with regards to its ability to produce within budget, complete within time and also produce a project which can stand the test of time and also satisfy the purpose for which it was implemented. This research therefore evaluated 62 DBB and 17 DB completed projects in the Greater Accra, Ashanti and Brong Ahafo regions of the country. The study further undertook a comparative analysis of 15 similar projects from the total number of projects evaluated to ascertain whether or not there is a significant difference between the performance of the similar DBB and DB projects studied. The study further identified the reasons behind the projects performance disparity between the two methods. The study gathered historical records of completed DBB and DB projects between 2000 and 2007 and also sought respondents opinion on which of the 35 factors listed was critical to the success of the project on which information was provided. The data gathered was analysed using analysis of variance with the aid of Statistical Package for Social Sciences (SPSS 13). The success factors were also identified by subjecting each of the factors to significant test at 99% confidence interval. The study revealed that most DB projects are completed within their respective budgets whilst a greater number of DBB projects incur cost overruns due to variations and price fluctuations. The time performance comparison also placed DB projects better than their DBB counterparts as most of the DB projects were completed within programme. The study further revealed that, there is no significant difference between the qualities of completed projects executed under the two procurement methods. Out of 35 factors listed, 11 were identified as significant to the performance of DBB projects which are: awarding bids to the right bidder, availability of resources, clients’ ability to adequately fund the project, overall managerial action in planning, organizing, leading and controlling, project team leaders’ commitment to time, cost and quality, inflation, interest rates, payment procedures, arbitration as a method of conflict resolution, progress meeting and control mechanism of sub-contractors work. Six (6) factors were also identified as significantly important to the success of DB projects. These are: awarding bids to the right bidder, availability of resources, clients’ ability to adequately fund the project, overall managerial action in planning and organizing, contract documentation and project team leaders’ knowledge and skill (competence). (Keywords: building projects, traditional design-bid-build (DBB), design and build (DB), success factors and project performance)
A Thesis submitted to the Department of Building Technology, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the degree of Master of Science in Construction Management.