The following are the three most common types of primary obligations adopted in a main contract:

Design and construct: 

The project owner provides the contractor with an outline design of the project.

The contractor undertakes the detailed design in accordance with the outline design, and constructs the project to the detailed design.

The contractor is responsible for:

• design outcome
• the performance of sub-contractors and suppliers
• construction outcome.

Construct only: 

The project owner provides the contractor with the detailed design of the project. 

The contractor constructs the project to the detailed design.

The project owner is responsible for design outcome.

The contractor is responsible for:

• the performance of sub-contractors and suppliers
• construction outcome.

Manage only: 

The project owner provides the contractor with the detailed design of the project. 

The contractor appoints sub-contractors and suppliers on behalf of the project owner.

The contractor manages the construction of the project to the detailed design on behalf of the project owner.

The project owner is responsible for:

• design outcome
• the performance of sub-contractors and suppliers
• construction outcome.

The contractor is responsible for failures in its management responsibilities.