Seismic & HVAC Upgrades

The Historic Governor's Mansion

The necessity of removing virtually all the building's interior surfaces after the 1993 fire provided an opportunity to upgrade the building's structural, mechanical, and electrical systems.

Like most historic buildings, the mansion was not built to withstand the back-and-forth motion of an earthquake. Ken Willmore, principal in Tanner Willmore Smith of Bountiful, created a computer model of the mansion in order to assess its structural weaknesses. The analysis revealed several surprises:

  • The walls were unreinforced masonry.
  • The roof , walls and floors were not connected to each other or to exterior masonry

The building was in poor seismic condition. In order to reduce earthquake risk, structural elements had to be strengthened and "connected."

A horizontal truss system was constructed to extend the floors in preparation for their attachment to the exterior walls. Then the truss was epoxy-bolted to the exterior limestone and tested at twenty pounds per square inch to determine strength. Since the first floor was weak, thick steel straps were bolted to brackets which were epoxied into the granite foundation."

The Historic Governor's Mansion

Exterior walls were anchored to the brick at each level so the building would move in unison. The roof structure was strengthened and secured to the walls. As a result of these upgrades, the building will withstand earthquake tremors more safely than before the fire.

New electrical and mechanical systems were constructed, including new heating, air conditioning and plumbing. New communications systems incorporating fiber-optics were also installed. Fire Protection Consultants, Inc. designed a fire suppression system that was installed by Delta Fire Systems; both are Salt Lake City firms.