How do you move a 2-million pound post office?

Its temporary relocation was completed last week to allow for the excavation of an underground parking garage that will serve a new office and retail building, which will be integrated behind the old U.S. Postal Service lobby.

Officials broke ground on the project late last year, revealing the creative plan to slide the 1,000-ton lobby, including its front courtyard area and steps, onto an adjacent parking lot. The structure is planned to be pushed back into place and joined to the new development in 2023.

“The engineering and construction techniques being used to preserve this community asset are a wonder to watch,” Councilmember Donna Colson said of the complex endeavor.

The post office was in use until 2014 and in 2020, amid plans to redevelop the site, parts of the structure were added to the city’s historic resources register. Plans are to restore the lobby, repurposing it as dining space opening up to a plaza that will replace the parking lot. From behind, the new structure, to be the tallest in downtown, will raise six stories with large windows and terraces at each level.

While a plan to build the two-level, 275-spot parking garage with the lobby in place was considered, engineers determined doing so would prove problematic.

“I thought there was a better solution because the configuration of the post office lobby is long and narrow and would be a nightmare to support laterally,” said Jim Salata, owner of Garden City Construction, the company in charge of the task. According to Salata, digging underneath the lobby would have required installing temporary piers that could have become damaged during excavation.

Instead, the lobby was separated from the larger portion of the post office building by cutting through the concrete walls and foundation, explained Steven Duquette, owner of Duquette Engineering, a firm brought on to assist with the task. From there the building was lifted using 80 synchronized hydraulic jacks.

“Once the building was up on jacks, we learned it weighed more than 2 million pounds,” Salata said, who added the discovery meant more steel beams were needed to support the structure than initially thought.

With the building lifted, 14 such beams were installed under the building along with specialized rollers, and 10 hydraulic rams were used to pull the building to its temporary resting place. The move was carried out over two days, 60 feet per day. Duquette said the steel used to move the building weighed more than 250,000 pounds.

Adding to the challenge, he said, the building had to roll over a large drainage culvert. To support the beams over the culvert, 20 concrete piers had to be installed in the ground at depths up to 35 feet, essentially building a bridge over the uneven ground.

The post office will undergo restoration where it sits today before moving back into place. The entire project is slated for a 2023 completion, with the adjacent plaza planned to begin construction in 2024.

“It takes a village on a job like this, and I’m sure there will be future projects where we will use this strategy again,” Salata said.

The plaza is envisioned to be a new town square, capable of hosting events and serving as a gathering point for the downtown area. The new building, combined with the post office space, will comprise nearly 185,000 square feet.

The project is being overseen by Sares Regis Group and Dostart Development Company, which will provide $2 million to the city for the town square development, as well as an additional $3.5 million to go toward affordable housing in Burlingame. While a total cost for the project was not provided, the developers last year secured $184 million in construction financing.

corey@smdailyjournal.com

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