Design-build with a development phase:From creation to first projects and related experiences

Design-build (DB) is a much-used project delivery system with operational variations for different needs and situations. This publication focuses on a novel DB variation that exploits the parties’ collaboration in order to improve the economic efficiency of construction projects: it is called “design-build with a development phase” (DBd). More precisely, this publication presents the DBd procedure and how it was initially constructed to mitigate the drawbacks of conventional DB practices and eventually applied to a few infrastructure projects.In the DBd procedure, the owner and the selected contractor continue the development of the project solution in cooperation, adhering to the principle of benefit sharing that is enabled by the benchmark solution, formed as a result of the price-inclusive contractor selection. Yet, the procedure does not require the inclusion of the design solution in the proposal. Instead, the owner ensures that the design solution of the chosen contractor meets the set requirements during the contractual development phase that precedes the realization. The development phase ends when the owner makes a decision about exercising its option for the implementation phase, which follows the usual DB contracting practice.As for the first DBd application projects, the experiences were positive, and the project participants believe that the procedure can be beneficial to many challenging projects with leeway for development. The procedure enables joint development by the owner and the contractor for more economical project solutions. It may be a question of critical evaluation of design principles based on more comprehensive knowledge, but the procedure also encourages the search for better solutions within the set requirements. The production viewpoint is taken better into consideration and no major uncertainties plague the implementation phase since the preceding development work helps eliminate them. It is thought that increased dialogue combines the parties' know-how for the benefit of the project, even if there were veryfew striking changes