Applicability of design bid-build and design-build-maintain delivery methods to road sector projects in Rwanda

Abstract

The Government of Rwanda is investing much money for upgrading the size and quality of the roads infrastructures as the key factor of economic growth of the country. In order to meet this, the Government has established the Rwanda Transport Development Agency as the government institution in charge of the development and construction of the road projects and being sure that the projects are timely and cost effective. Every project is considered successful if it is completed with contractual cost, meet with contractual period and better quality of the end product. The roads projects in Rwanda experienced the cost and time overruns from the terms of the contracts. The main causes of these overruns are related to the variations and changes orders occurred during the projects implementation, there are many reasons in Rwanda which could cause the projects to be unsuccessful and the use of the various projects contracting methods which best fits with the projects can reduce the problems. A project can be implemented through design bid build, or innovative methods which includes design and build, design build and maintain and construction Management at Risks. The present research analyzes the applicability of the DBM and DBB delivery methods to assess if one of them can be more advantageous compared to another in terms of cost and time. The factors which could influence the proper execution and successful of roads projects in Rwanda for both methods were explored through literature review. The desk study, questionnaire survey and case studies are used in this research as the research instruments. Data were collected from fifteen samples projects of RTDA among of which six samples are the projects delivered through DBM and nine of them are the samples projects delivered through DBB method, the collected data have been evaluated, analysis and discussions are made on the results. If Design Build and Maintain delivery method is used, there is more chance to complete a project within provided budget and time. Cost and Time overruns are higher in DBB projects compared with DBM. The causes of the cost and time overruns in the projects delivered with Design Bid and Build method are mainly due to the additional works, variations, design changes and ROW Particularly, the following factors need to be considered for getting the better results from DBM:

✓ Clients must be capable to certainly and explicitly define his expectations, definition of the requirement and end user needs. ✓Conclusions would retain effective fast-tracking on the design documents and construction. ✓For preventing the quality issues over DBM, the approval of the design documents should be strict.