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.

Why it matters: The UCSF New Hospital at Parnassus Heights (NHPH) team installed oxygen tanks without disrupting the flow of oxygen to the existing hospital. When activated, the tanks will supply oxygen to both the existing and new hospitals.

• It took a year and a half of preparation work, beginning in December 2022, to install the tanks.

The big picture: The installation site on Mt. Sutro required significant preparation. Superintendent Saleh Fadhel said the team had to shave part of the hill and build a massive shoring and retaining wall.

• "We installed 380 soil nails, spanning from 40 to 85 feet long, to stabilize the hillside," he explained. This was followed by creating a shotcrete wall, foundation piles, a mat foundation, and a slab on top of the mat foundation before erecting the steel structure that encloses the tank yard.

Given the complexity and size of the tanks � one 9,000-gallon tank and two 11,000-gallon tanks, each nine feet in diameter and 35 feet tall � logistics played a crucial role.

• The tanks were transported from the Midwest, and meticulous planning was required to move and install them. "We coordinated with Bigge to set up cranes within the project fence and in the oxygen tank yard," Saleh noted. "The installation involved six pieces of equipment, and we had to work on a Saturday to avoid the busy weekday traffic."

The tanks were installed on piles with anchor bolts about 12 feet long, embedded in 40-foot-deep piles. "Each tank has three legs, and each leg sits on a pile with four anchors," Saleh described. Despite facing challenges with alignment, the team successfully installed the tanks by the end of the day.

Go deeper: The installation was a collaborative effort involving multiple parties, including the contractor's team, owners' representatives, subcontractors, and specialists.

The team worked together to make on-site modifications, ensuring the tanks were installed correctly. "It was mind-boggling and awesome at the same time to see everyone come together to meet the deadline," Saleh remarked.

Next Steps: With the tanks in place, the project is moving into the testing and commissioning phase. The oxygen tanks, complete with vaporizers that convert liquid oxygen to gas, will soon be operational, ensuring a reliable oxygen supply to the existing and new hospitals.

by Nick Borov, Project Engineer

The Contra Costa County (CCC)Admin Building and Jail Demo & Redevelopment (ADR) has all but wrapped up the interior side and is now resolving all outstanding punch list items in the race to final completion. Soon, we'll begin handing over the keys to selected rooms--an exciting sign of final turnover--before the County starts delivering their permanent office furniture.

The car stacker system is now fully operational within the garage space. Moving outside, we're proud to say that the unforeseen underground storage tank has safely and successfully been removed. We've been working diligently to make up for the time lost to this delay. The last of the utility work was completed in February, and the remaining concrete pavement and pavers have all been installed, resulting in a substantially complete Pine Street walk/roadway.

Serving as the centerpieces of our courtyard, five 40-year-old olive trees have been successfully delivered and planted. Site furnishings have all been installed as well, including light poles, benches, bike racks, and gameboard tables. Punch for the site is scheduled within the next week.

Also worth a shout-out: As part of our team's sustainability and gritty frugality efforts, we've successfully transferred our site fence over to the UCSF NHPH job! After standing in Martinez for more than two years, these plywood walls will continue to be used in San Francisco for years to come.