Using a relatively new Progressive Design Build (PDB) contract model led to increased collaboration, more innovative solutions, better designs and more accurate estimates and schedules on two recent water projects in Southern California.
What’s different about the PDB model is the preconstruction phase where contractor and client come together to understand project end goals and identify innovative solutions that optimize the right combination of cost, schedule and risk transfer between the parties.
Contract price, schedule and terms are not fixed until the design is 60% to 100% complete, according to William Searles, vice president of preconstruction services for Kiewit Water Markets and Strategy.
“As you progress through the scope generation and design phase, we don’t have the pressure of operating under a fixed price or schedule,” he said. “That frees us up to be a solutions provider, to bring ideas, to be able to really understand what the client is looking for, what their end goals are for the project and what their budget is.”
At some point when the design is at least 60% complete, the client and contractor decide the scope of work is fixed enough where risk can be transferred from client to contractor. They settle on a Guaranteed Maximum Price and issue a contract amendment for the construction phase of the project.
SWIP Project in Santa Monica, California
Kiewit Infrastructure West Co. led preconstruction services on the $88 million Sustainable Water Infrastructure Project (SWIP) for the city of Santa Monica and was then selected to complete the construction. The PDB model allowed the company to identify several client cost-saving solutions early in the design process, including:
– A way to use the city’s existing storm drain infrastructure and construct a stormwater storage tank at the main site rather than design and build new tanks at two different sites. This eliminated four stormwater tie-ins and avoided the need to lay stormwater pipe under a live light rail track. The solution saved the client $5 million and eliminated the need to close a popular public park for 18 months.
– A recommendation to replace a 4.5-million-gallon stormwater harvesting tank with a 1.5-million-gallon tank to keep the project within the client’s budget. – Creative temporary engineering solutions for excavation, shoring, and process tie-ins.
“On the SWIP project, Kiewit has been our partner throughout the project,” said Alex Nazarchuck, city engineer for the city of Santa Monica. “They’ve taken on our challenges and problems like they were their own and worked with us to solve them.”