Advocates of lean construction recommend early contractor involvement (ECI) to further reduce waste. Waste reduction and flow, value generation and sustainability can be improved if some of the companies on a project use lean principles and methods. However, if the contractor is organizationally integrated in the early phases, there is a better chance that the product and process designs are consistent with one another. ECI can ensure better value for money by organizationally integrating contractors` knowledge to early phases of projects. This paper contributes to the knowledge about how to implement ECI in public projects. In addition to a literature study, a document study as well as fourteen semi-structured in-depth interviews with key informants from eleven Norwegian public bridge projects were carried out. The EU public procurement directive represents a challenge for public owners when they consider ECI in their projects. However, the studied bridge projects have used various approaches to implement ECI without violating the EU directive. Thirteen approaches are identified in this study. The conclusion is that there are several approaches to implement ECI in public projects, though the contractors’ contribution varies a lot depending on which approaches that are implemented.
Lean construction, ECI, Project alliancing, Public procurement, Knowledge integration.