Seismic Upgrades at the Salt Lake Temple
What did the seismic upgrade entail?
The core of the seismic upgrade was installing a state-of-the-art base isolation system beneath the entire temple foundation. This system includes nearly 100 advanced base isolators that allow the building to sway safely up to five feet in any direction during an earthquake. This dramatically reduces seismic forces transmitted to the structure, protecting both its historic integrity and its occupants.
Additional improvements included:
- Deep foundation reinforcement via “jack and bore” technique: steel tubes filled with concrete inserted beneath the existing footings.
- Vertical coring: 46 holes approximately 150 feet deep were drilled through the granite walls to install post-tensioning cables, anchoring the spires to the reinforced foundation.
- Structural enhancements such as steel roof trusses were added to support the spires and improve overall seismic resilience.
Process and Timeline
- Start date: The seismic upgrade work began in late 2019, coinciding with the broader renovation project.
- Major seismic work completion: Most of the foundation reinforcement, base isolator installation, and structural strengthening was completed by 2023.
- Overall renovation finish: The entire project, including seismic upgrades, was finalized in mid-2025.
Cost of the Seismic Upgrades
The total renovation budget for the Salt Lake Temple, which included seismic retrofitting, restoration, expansion, and upgrades, was approximately $125 million. The seismic components represented a significant portion of this overall cost, reflecting the complexity and importance of safeguarding this historic landmark.
Were there any issues during the seismic upgrade?
The project faced typical challenges, such as:
- Ensuring precise installation of base isolators to avoid damaging the historic exterior and interior.
- Carefully drilling into and reinforcing the granite walls without causing damage or visible disturbance.
- Balancing seismic safety with maintaining the aesthetic and historic integrity of the building.
Fortunately, no major delays or structural issues emerged, and the project was completed successfully.
Seismic Upgrades to the Joseph Smith Memorial Building
Yes, the Joseph Smith Memorial Building also received seismic improvements as part of its comprehensive renovation:
- The scope included foundation reinforcements and structural strengthening to meet current seismic safety standards.
- Specific details and costs are less publicly disclosed, but the entire renovation project for the building was approximately $55 million, with seismic upgrades accounting for part of this budget.
Other Buildings on the Temple Grounds
While the Salt Lake Temple and Joseph Smith Memorial Building underwent significant seismic upgrades, other structures like:
- The Conference Center
- Visitor Centers
- The Church Office Building
may have received minor or routine safety updates, but there are no publicly available reports of major seismic retrofitting similar to those at the temple and memorial building. These larger structures are now built or upgraded according to modern seismic standards during their original construction or subsequent renovations.
Summary
- Salt Lake Temple: Major seismic retrofit with nearly 100 base isolators, deep foundation reinforcement, wall coring, and structural supports. Work started in late 2019 and finished in mid-2025, costing around $125 million. No significant issues reported during construction.
- Joseph Smith Memorial Building: Also received seismic strengthening, with costs incorporated into the total renovation budget (~$55 million). Specific details are less public.
- Other Structures: Likely received routine safety updates; no publicly disclosed major seismic projects.