Renovation Silver: On the hill
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Since it was originally completed in 1916, Utah's State Capitol building has been a landmark of civic pride. Modeled after the nation's capitol, the Salt Lake City building architecturally echoes its Washington, D.C., sibling.
Previous renovations to house modern electronic conveniences and other modifications left the building a shadow of its former self, with many false ceilings that covered up historic handcrafted details. The state's other major concern: upgrading the building to withstand a sizeable earthquake, since the capitol is used as an emergency command center.
“The plan was to return it to its original glory and breathe new life into it,” said David Wesemann, Salt Lake City-based Spectrum Engineer's lead engineer for the project.
Challenges and solutions
One of the biggest tasks for the 330,000-sq-ft state capitol was installing 265 base isolators that would protect the capitol from earthquakes up to an 8.0 magnitude. The entire building was jacked up. Shock absorbers were placed on a podium that acts as a terrace around the capitol and creates a 50-ft barrier to potential terrorist activity. A 3-ft-wide mote of air circles the building, allowing enough space for the capitol to move independently during a seismic event. The other major issue engineers faced was renovating the capitol to its original historical design while unobtrusively adding electrical and mechanical systems. The design team ran some ductwork through discontinued airshafts, disguising it in the attic and basement of the building to leave critical historic areas unaffected. Instead of sacrificing historic ceiling space, Spectrum removed the false ceilings that had been installed in earlier renovations and restored the original handcrafted plaster ceilings. Then the walls were thickened for ductwork in vertical distribution.
“It was a year and half of weekly meetings to make sure every single duct would coordinate,” said Todd Rindlisbaker, Spectrum's project mechanical engineer. “There were a lot of surprises that we wouldn't discover until demolition because some of the concrete beams ran in different directions or weren't as wide as they were shown on drawings from 100 years ago.”
Because the ductwork was vertically stacked, if one floor had to be changed, it affected the two floors above or below the two-tier system. After designs were planned around 48 in. of space in the attic for ductwork, the team discovered that only 30 in. remained between the roof structure and the floor of the attic. That meant redesigning the entire quadrant of the building with flat oval ductwork, instead of round, to save space.
Spectrum also performed an energy impact study and changed the electrical distribution specifications from 3 + 3 (three conductors with three dedicated neutrals) to 3 + 1 with an oversized shared neutral and more than 2,000 branch circuits totaling about 1.8 million ft of wire. This resulted in $20,000 in immediate savings and $7,000 in annual energy savings.
The architects wanted the building to appear just as it had in the early 1900s, which meant that smoke detectors had to be hidden in lighting fixtures and cove moldings. Old photographs were used as models for traditional lighting and plumbing fixtures. Original lighting fixtures were restored, refurbished, or replicated. To re-create historic lighting levels, which were darker during the early 1900s, the architects used incandescent lamps, which accounted for 8% of the new lighting fixtures. They were used in special rooms, like the Governor's Ceremonial Office and the Gold Room, where dignitaries meet the governor amid antique furniture, gold leaf accents, and restored chandeliers. The other 92% of lighting fixtures use energy-efficient fluorescent, HID, or LED lamps.
The $212 million capitol renovation project began in design in 2002, with demolition in September 2004. The project was completed in December 2007 and dedicated a month later.
“There's always a great sense of satisfaction when you finish a project,” Wesemann said, “especially since this renovation was designed for the next 100 years and you know it's going to be used by your children and grandchildren.”