Abstract
In recent years, the design build contract scheme is expanding to use not only the developed countries but also in the developing countries. The design build contract scheme is able to improve project quality, time and cost combing the ideas coming from both design works and construction works. This contract scheme also is able to provide a big chance to contractors and consultants to get out from traditional business way and to increase their project execution ability. It has already started to apply this contract scheme to the public projects in japan. However, contractors do not like to accept this scheme because of unrealistic risk valance between the owner and contractors. The risk valance is the quite essential matter when you discuss about a contract scheme. But in Japan, people have a tendency to mix up tendering scheme and contract scheme. This paper is discussing about the solutions to the problems related to the design build contract in Japan by applying design work layered structure, such as basic planning, conceptual design, basic design, detail design and manufacturing design.
