Optimizing Construction through Design

This article is included in the Great Things: Issue 6 edition of the DPR Newsletter.

prefabricated rebar cage is lowered with a crane into a trench
A life sciences project in the San Francisco Bay Area is applying elements of a design-to-build approach to project delivery. Courtesy of Congregation Media

If you’ve ever tried to assemble furniture from a kit of parts, you’re probably familiar with the simple instructions that (hopefully) come included. While actual experiences may vary, most would agree that it’s a preferable starting point compared to building from scratch.

The same idea can apply to buildings. By using the same principles of manufacturing, building designs can be optimized so that certain components can be prefabricated and assembled on-site in less time, driving value and quality beyond traditional delivery.

The concepts of Design for Manufacturing and Assembly (DfMA), prefabrication and modular construction aren’t new. They do, however, inform an approach to project delivery that closes conventional gaps between design and construction regardless of project size, type or contract. It’s called design-to-build.

“Design-to-build is about shifting how we look at the entire method of developing and delivering a building,” said Zach Murphy, DPR’s design-to-build leader. “Most projects are built in a sequential workflow in which one party hands off the design to another. When you follow design-to-build processes, the whole delivery becomes more collaborative and that unlocks ways to optimize the design so it’s easier and faster to build.”

man aligns rebar cage into trench
The idea to prefabricate rebar cages coincided with ideas that DPR’s self-perform work group were already developing to deliver a faster and safer project through prefabrication, VDC, and design resources with the help of strategic partnerships. Courtesy of Congregation Media

Savings on the Critical Path

One project putting elements of this approach to the test is a three-story 150,000-sq.-ft. ground-up life sciences manufacturing facility in the Bay Area for 10x Genomics. The building, which broke ground in August 2021, will also include laboratory clean rooms and office space as part of the company’s expanding research, development and manufacturing capabilities.

A lengthy permitting process paired with an ambitious schedule meant the team had to find ways to save time on the critical path. They focused on one area that would allow them to accelerate the schedule: the building foundations.

“We knew we had to be creative in how we thought of both cost and schedule,” said Becky Chahal, DPR project executive. “When we looked at some of the time crunches, one of them was around foundations and getting our steel. We knew decreasing the time spent on installing the rebar would help us.”

This coincided with ideas DPR’s self-perform work group were already developing to deliver a faster and safer project through prefabrication, virtual design and construction (VDC) and design resources with the help of strategic partnerships.

Chavez Grieves, the structural engineer of record, worked with GPLA, a Bay Area-based engineering firm, to apply DfMA principles to streamline foundation design and meet California building code. The result was inspired by GPLA’s work on past projects that used prepackaged assemblies: rebar cages that were prefabricated by ConCo Rebar and then tied and lifted into place.

“The exchange of ideas with DPR and GPLA were absolutely collaborative,” said Nicholas Torres, vice president and principal at Chavez Grieves. “Anytime the design team can collaborate with the constructors to design a custom and creative solution for the project, everybody wins.”

Torres noted that unless this happens, designers have to try and guess, or use outdated metrics on what they believe to be the best and most economical solution for the specific project.

“Once everyone was on the same page, we weren’t trying to regurgitate information differently, we could share the models. Everyone understood that it wasn’t just one party trying to take over the design but all of us working together,” said GPLA’s Patrick Ripley, who led HD BIM detailing for the project’s concrete and steel reinforcement scopes.

Ariel view of project site prior to concrete pour
To save time on the schedule and get steel in faster, the project team turned their attention to the building's foundations. Courtesy of Congregation Media

How Do You Want to Build It?

Input from DPR’s self-perform crews was central to the development of the foundations. With their feedback GPLA created a sequencing document (literally the instruction booklet) for taking the prefabricated components and assembling them onsite. The crews’ comments on specific constructability details led to informed decision-making to help streamline installation.

“The craft have to be tied into the process because we can model the structural drawings, but a lot of it is coordinating with the field foreman on how to work the job,” said Ripley.

The 40-ft.-long rebar cages were placed spanning the column lines, making it easy to install complementary anchor bolt embed assemblies. The integration of all parties—design team, rebar trade partner, and DPR’s own self-perform concrete crew—enabled improvements that led to success.

“Considering the length, width and weight of the materials being placed in our footings, we saved six people two to three days of work,” said Dustin Wynne, DPR concrete superintendent, of the embed installation process.

Two men pour concrete
Input from DPR’s self-perform crews was central to the development and installation of the foundations. Courtesy of Congregation Media

Planning it Right

“The process drives more discipline in how we schedule the job and in how we incorporate our sub-contractors,” said Jon Shores, DPR self-perform concrete project manager. “We saw some significant production increases out of our reinforcing contractor.”

When every bolt needs to be level to support the column that will go on top, precision is everything. And while most projects might expect to account for corrections after the initial install, this project didn’t have to. Zero RFIs were issued on the entire rebar scope, and all anchor bolts were installed without any tolerance issues.

“This approach forced us to plan it right, it forced us to model everything. We understood where we had conflicts and how we could correct them before the rebar was fabricated, and way before it ever got installed, so when it got here it was correct,” said Clark Chatterley, DPR general superintendent. “It truly went in the way we modeled it.”

“This is really about multiplying the benefits of implementing VDC, prefabrication, self-perform and design-to-build strategies together,” said Jack Poindexter, DPR’s self-perform work lead for the Northwest. “In isolation they all provide value to projects, but together you get results like this.”

Field Notes for Future Applications

If there’s one thing that the project team would do differently on their next job, it’s to integrate the team even earlier. As with any project, getting all stakeholders aligned took time and the different approach necessitated even more attention to site coordination, logistics and planning to ensure the safety of everyone working on-site. Despite the hurdles, the gains in efficiency and quality speak for themselves.

“The importance of being able to understand the design early on, see how we can modularize certain components of the job, and see how those components can be prefabricated to help influence our cost and schedule can be really beneficial,” said Chahal. “How we approach this on future jobs is to allow our team to get with the design team as soon as possible so that those details can be worked through from the very beginning.”