If you’ve driven by City Hall in the last several months, you’ve undoubtedly noticed the large hole on the southwest side of the building. And if you’ve been inside the lobby, it’s a bit like standing on the edge of a small cliff as you look down at what’s been excavated in preparation for the new 21,500-square-foot police wing addition.
It was during preliminary excavation for the new addition to City Hall that the excavator realized the soil was unexpectedly sloughing off and falling in near the building’s rear entrance. Excavation halted and the rear entrance to City Hall was closed, its current status, but something that was never supposed to have happened.
Assistant City Manager Russell Fox said that the brick columns at the rear of City Hall are connected to the beam system, all of which support the front of the building. When the contractor began to excavate to get footing under those columns for the new addition, the sand in the soil started sloughing off and falling in. So that part of the project had to be re-engineered.
The contractor chose to put in Helical piers which are drilled down into bedrock and then will be surrounded by and filled in with compacted soil to shore up the columns as they tie into the new and existing structures. Helical piers are steel shafts that provide foundation support in construction.
“They weren’t expecting to have to support the columns like that. They had to go back and design this system,” Fox said. “Those are now really significantly supported,” he said.
Fox also explained that City Hall and the new police wing have to be built to Category Four standards, meaning that as an assembly area and potential emergency operations center in the event of a disaster, they have to meet higher seismic standards.
Think Architecture of Salt Lake City is both the architect and contractor on the project that will result in the new, three-level wing for the police department. Think Architecture also built City Hall.
Fox said that this discovery does result in higher costs for the project.
“But it’s not a cost that’s coming to the city,” Fox said as he explained that the agreement was that Think would build the new wing for a pre-determined amount of money.
Mayor Troy Walker said that the contractor is handling everything and that they haven’t asked for any adjustments to the contract.
“They’re doing it. It’s theirs to fix,” Walker said.
City Councilmember Bill Rappleye said, “The good news is that was included in our contract so there are no additional fees for us. It’s just part of the construction, and so it will take a bit longer. It’s being done correctly and that’s the important thing —a building we can use in the event of a catastrophic earthquake.”
Construction of the police wing began with a groundbreaking June 12, and initial completion was slated for June or July 2015. This development likely delays the project for roughly six to eight weeks. Meanwhile, the rear entrance to City Hall is expected to be re-opened in mid-December.