Progressive Design-Build — what it is and why we chose it

Along with pursuing funding and testing bedrock and soils, the project team has taken another step toward replacing the Hood River-White Salmon bridge: choosing a project delivery method. That sounds a little abstract, but it’s crucial.

A large engineering and construction project requires choosing the best way to design and build the project. We chose the Progressive Design Build (PDB) method. PDB is collaborative: The contractor and the designer work directly with the owner to reduce risk, save money and shorten the schedule without sacrificing safety or quality. Designers and builders working on the same team from the start will mean we get a better bridge faster.

PDB generally has two phases:

1.       Preliminary or preconstruction. The designer and contractor work collaboratively with the owner to design a project that meets local, state, and national requirements. The designer and contractor give the owner ongoing, transparent cost estimates. When the design is far enough along and all requirements are met, the contractor submits a formal design — including the overall contract price. The owner validates this price through an independent audit before agreeing.

2.       Final design and construction. When the owner and the contractor agree on the price, schedule and contract terms, the contractor makes the design final and starts construction.

That might sound like we don’t have much control over the final price — but really, we do:

• During design, the contractor gives the owner a guaranteed maximum price (GMP) at key milestones during the project — typically early in the design, midway through the design and before the end of the design. The owner validates that price through an independent audit at each step. If the price is outside the project budget, the owner will work with the contractor and designer to modify the design, never having to sacrifice quality or safety and keeping the project within budget.

• If the owner can’t reach agreement with the contractor on the price or contract terms, we can use an “off-ramp” option — keeping the design and finding someone else who can meet the price and contract terms.

Using PDB often saves money overall because it limits contract changes that can cost extra money. These changes can happen when the designer and contractor work separately and not collaboratively with the owner.

Keep in mind we have not chosen a contractor yet; we’ve chosen only the project delivery method. Since last fall, we’ve been doing geotechnical testing of the bedrock and soils, surveying and developing the materials needed to select the designer and contractor.  We had over 80 designers and contractors attend an online industry day. More than 30 potential designers and contractors have met with us one-on-one to understand the project better.  We’re on track to issue the request for proposal this fall and select a designer and contractor by the end of the year.