What the Salt Lake Temple Renovation Has in Common With an Aircraft Carrier
If the Salt Lake Temple were an aircraft carrier — and they do weigh the same — then you could say the temple will remain in dry dock in 2023.
The big difference between two superstructures that weigh 187 million pounds is that it’s a whole lot harder to move a 130-year-old granite temple into place for repairs.
In fact, workers have spent much of the past three years of the major renovation jockeying for position to build the new, underground platform that will protect the temple from major earthquakes.
It would have been easier to deal with an aircraft carrier, which displaces its weight across an area 12 times larger than the temple, according to a church video released this week.
To access the pioneer-era foundation, workers needed to excavate around it. The problem is that as they removed dirt around the base, all that tonnage threatened to push the earth directly under the temple out into the newly open space.
So workers installed a 40-foot wall, or giant collar, around the base of the temple to keep the earth under the temple in place while they installed reinforced cylindrical beams into the existing foundation.
That “jack-and-bore” process is still underway. When it’s done, workers will create a new, enlarged platform below the temple and its original and previously reinforced foundations.
The goal is simple, a complete seismic upgrade. It’s a monumental task, however, to reinforce the temple structure from its underground base to the tips of its spires.
The idea is that the temple will become a single, interlocked object that moves together when an earthquake moves the ground under and around the temple side to side.
The renovation is adding two major systems to make that happen.
First, workers are adding a base isolation system. That will isolate the temple from the shaking movement of an earthquake so that the earth moves beneath it while it remains more stable.
No base isolation system is perfect and can still allow some movement and damage, the video said.
So, second, workers are adding structural reinforcement systems throughout the temple’s walls, roof and towers.
These systems tie the temple together with steel and concrete. Here’s how:
Workers are reinforcing the temple’s roof with new trusses over the old ones. They also are drilling precise holes in the walls to to make room for steel cables that attach to the new base and run up to the roof.
The trusses, the new steel cables in the walls and the walls themselves are being connected together by new, reinforced concrete bonding beams across the top of the walls. This reinforces the connection between the side walls and the end towers, the video said.
With the temple held together as one above ground, the base isolation system will protect the temple from ground motion.
Throughout 2022, workers exposed the temple’s original footings, drilled holes in them and filled the holes with grout, steel rods and cable reinforcements. Those stone blocks and grout can carry immense weight but can’t prevent all damage.
So workers also have been placing reinforced cylindrical beams — steel pipes filled with concrete and cables — under the original footings in the jack-and-bore process.
This year, workers will begin the process of placing 98 base isolators under the temple. These look like giant blue hockey pucks. Each is 7 feet across and can hold 8 million pounds.
