Assessment of level of design completion prior of tendering in design and build urban rail projects

Implementation of projects by entering into a single enterprise which is responsible for all aspects needed for completion of work (Engineering, Procurement and Construction) has been widely used in many countries. This method has also been recently utilized in many multidiscipline projects such as Metro lines in Iran. As metro projects are multidiscipline and complex, selection of correct policy for project breakdown and contracting has great influence on final results. In design and build method, the owner usually performs preliminary design and the tenderers propose to perform detailed design and construction. In this paper, the authors based on lesson learnt of line3 of Tehran metro and line1 of Esfahan metro, have reviewed different methods of design works performed by owners prior to tender. Two Main approaches are proposed . 1-The owner performs conceptual design and completion of basic and detailed design will be performed by contractor. 2- The owner performs basic design and detailed design will be performed by contractor. Based on the author's experience, another option can alsobe utilized in which completion of design is under control of the owner using his staff or consultants like conventional design-bid-build method and the contractor is called to review the design and adjust it during construction period. Metro projects have special situation because of being done in urban environment and multidisciplinary. Advantages and disadvantages of each method are studied as summarized below: 1- In the first approach, by combining all aspects of design into a single contract, the contractor has a wide exchange operation but needs to great cooperation with owner to finalize

کلیدواژه ها:

Design and Build ، Basic Design ، Detail Design ، Bidding