Topping Out Ceremony Marks Major Milestone at SFPUC Biosolids Digester Facilities Project

Building 600, one of four buildings comprising the Biosolids Digester Facilities Project (BDFP), topped out recently, marking the completion of most of the concrete structure.

Why it matters: Building 600's unique design and construction challenges stand out from the other BDFP structures.

• The tallest part of the structure is the elevator core, which required pouring walls and ancillary decks, a departure from the norm, where the highest level is usually predetermined.

The team poured the last perimeter wall on May 21. While the metal deck and steel erection will continue into early July, the significance of this date was not lost on the team despite a planned reduction in crew size in the coming weeks.

Go deeper: The "tour route" observation area is a noteworthy feature of Building 600. This corridor allows visitors to view the processing activities from above, offering a glimpse into the project's operations from each floor. The architect deemed these areas to require a higher quality of finish. They were treated with the same care and attention as the building's exterior architectural concrete, ensuring a polished and professional look.

• The team continues to hear compliments about the exterior architectural walls. "They came out really great," said Webcor Concrete Superintendent Daniel Rinaldi (who has since left the company). "It's a testament to everybody on the team. We were lucky enough to have the same people pour every single floor. They're meticulous. They know it's important. It takes a talented group to pull this off."

Zoom in: One of the most complex coordination efforts involved the installation of three 63,000-pound hoppers on the level one slab. These massive pieces of machinery, essential for the project's operations, required 18 months of meticulous planning.

• Fabricated in Los Angeles, the hoppers were shipped in sections, welded together on-site, and hoisted into place. The team overcame numerous challenges, including delays, to integrate these crucial components into the structure.

The project began under challenging conditions, with late changes to the mat foundation and continuous rain during the foundation pours. The team had to adapt, working staggered shifts and starting early to avoid the heaviest downpours. Despite these obstacles, they managed to pour the 150,000 square feet of walls and complete the structure, maintaining a steady workflow and keeping the project on schedule.

• The team worked staggered shifts and started early, knowing rain would start by 10 a.m.

"It sucks to deal with rain, and it can suck to have people work in the rain, but it also sucks to have to reschedule pours," Daniel said. "We found a good balance for managing work during the rain cycles. Most days, it doesn't rain for 12 full hours, so you find the right balance, doing other work during the downpours."

• The irregularity of the interior and exterior walls on every floor added another layer of complexity. However, the collaboration and coordination between the Webcor-MWH and the subcontractors ensured a seamless sequence of work.

The backstory: Concrete work for the project began 18 months ago, with foundation work starting in December 2022. As the project progresses, the team remains focused on maintaining the high standards and quality that have characterized their work.

• The project's field staff comprised about 50-55 people, with eight additional office staff members.

The team held a barbecue prepared by the Webcor Craft barbeque team to celebrate the topping out. About 350 people attended. The event featured a few speeches recognizing the efforts and contributions of everyone involved.