Traditional Building Portfolio




A Singing Endorsement

Project: The Salt Lake Tabernacle, Salt Lake City, UT
Architect: FFKR Architects, Salt Lake City, UT; Roger P. Jackson, AIA, principal

By Lynne Lavelle

On July 15, 1929, the first broadcast of "Music and the Spoken Word," from Salt Lake City, UT, began with the following: "From the crossroads of the West, we welcome you to a program of inspirational music and spoken word." Like much of the half-hour feature, this introduction remains unchanged today, and is carried by more than 2,000 radio, television and cable systems every Sunday.

"Music and the Spoken Word" has been broadcast from a number of national and international locations, but its home – and that of the 360-strong Mormon Tabernacle Choir – remains the tabernacle on Temple Square. Built between 1863 and 1869, the building's turtle shape effectively and naturally amplifies church leaders' voices, and proved so popular upon opening that a balcony was built in 1870 to accommodate the growing congregation. The tabernacle remained virtually untouched for the next 130 years – a period that saw great technological strides in lighting, and of course in broadcasting and recording technology. All were accommodated within the original design, albeit with some visual clutter, until one day church leadership asked the very pertinent question, "How would this building cope in an earthquake?"

Using an earthquake simulation program, FFKR Architects, also of Salt Lake City, investigated the effect that the Northridge California quake of 1994 would have on the 97,000 sq. ft. tabernacle's giant stone piers and wood trusses. The answer was not favorable: "The study showed that the big stone piers, which are three ft. wide, nine ft. long and vary in heights from 12 to 21 ft., would start to tip over," says Roger P. Jackson, AIA, principal. "And at about the same time, the big wood trusses would slide from the tops of them. So to the question, 'How would it cope?' the answer was, 'Not very well.'"

On the basis of the data, church leaders commissioned FFKR to carry out a feasibility study on a comprehensive seismic upgrade, which identified the need for removal and replacement of all building, mechanical, electrical and broadcast systems. Studies also identified fire and crowd management issues with the balcony; it took twice as long to vacate as the main floor and could only be accessed via exterior doors. Additionally, since the building accommodates a variety of uses, the building owners requested additional flexibility in the arrangement of the rostrum.

Working closely with structural engineers Reaveley Engineers and Associates, and general contractor Jacobsen Construction Company, Salt Lake City, UT, FFKR began work in 2002. The project was a delicate balancing act, as the building owners specifically requested that none of the upgrades have any visual impact. "But in the meantime," says Jackson, "we had to pull out 130 years of leftover wires that people had just cut and left in place, and we had to bring it up to code and upgrade the technology for the ongoing broadcasting requirements. It really was a matter of stitching together all of the pieces."

Much of the tabernacle's seismic vulnerability was due to the isolation of its 44 stone piers – "nothing was really tied together," says Jackson. The firm reinforced these giant piers with a "saddlebag footing," whereby each was core drilled, and then strengthened with reinforcing bars. The footings were linked at the base with a below-grade wall, which also ties to the floor, and braced at the top with a horizontal steel truss between each pier. "The floor acts as a stiffener to hold all of these columns in place," says Jackson. "And at the top, one column can't tip over without pushing one neighbor and pulling the next."

The stone piers support giant wood lattice trusses, which are elliptical in shape; half trusses, arranged radially, form a semicircle at either end. As the "king trusses," which support the radials at either end were heavily over-stressed, the design team added a steel "sister" truss to assume the load – a tricky process given the commitment to conserving the building's original appearance. "We didn't want to take off the whole roof, unzip everything, to drop in a big truss all at once," says Jackson. "We kept the plaster finishes and we didn't know the damage that would be caused to the them if we took the whole roof off. So we'd take off a small section, slip in a piece of the new truss, build the roof back, take off some more, build the roof back… and so on, in sequence, until the truss was in place, carrying its own weight." Lastly, the weight of the old truss and the radial trusses on the ends, were transferred to the new truss. "That was a tricky day," adds Jackson.

Prior to the installation of a new aluminum roof, the firm installed a new diaphragm of half-inch plywood over the old roof sheathing – as opposed to utilizing a complex system of cross-trusses and ties. This new diaphragm, attached to the roof sheathing and the tops of the trusses, also provided additional stiffness and stability.

After the stone footings and wood trusses, the tabernacle's next biggest liability in a seismic event was its priceless 32-ft. tall, 11,623-pipe Aeolian-Skinner organ. Since reaching its present size in 1915, the organ has had a unique sound that is the pride of the Tabernacle Choir. Rocky Mountain Organ Co. of Salt Lake City painstakingly cleaned and stored each piece, from the largest pipes to those the size of pencils. The structure was stabilized, and the organ casework, woodwork and gold leaf refinished before the entire instrument was rebuilt.

Preserving the organ's sound was central to the entire project and, aside from the restoration of the instrument itself, required consistent attention to the acoustical effects of each and every upgrade. "We did a lot of work that could potentially change sound absorption," says Jackson. "We supported – and therefore stiffened – the giant plaster ceiling, and we took out some of the seats, changing the distribution of people, who absorb sound, in the room. We worried that these changes would alter sound of the room, and we knew that they had to be offset in some way."

The original lime plaster ceiling had been reinforced with animal hair and covered with approximately 14 layers of paint, many of which were lead-based. After stripping the paint with a series of organic chemical removers, FFKR and Evergreene Architectural Arts of New York City tried a variety of different re-patching materials, aiming for the cleanest finish and best acoustical result. With the help of a Brigham Young University masters student in acoustical engineering, the team used pre-testing data to analyze small patches and assure that the new plaster would have similar acoustical properties. Even so, the process was hit-and-miss. "We found a plaster that was very good, but wouldn't adhere to the old stuff," says Jackson. "But we managed to find another plaster product that would adhere well, was the right color and had the right properties. All to preserve the signature sound of the organ and the acoustics of the hall."

While most of the signs of restoration are carefully concealed below grade or in the attic, some improvements are deliberately visible. To improve circulation to and from the balcony, FFKR added two new stairs for balcony access, and modified the original exit stairs to connect to the main hall. Replica pews are spaced further apart, increasing comfort but reducing capacity by around 1,200 to 3,500. The new rostrum now accommodates several physical arrangements, including small conference with the pulpit down low; large conference with the pulpit at the upper level; and a full orchestra set-up and smaller stages. "With our stage consultant [Tom Neville at Auerbach, Pollack, Friedlander of San Francisco], we developed a series of modular pieces that could be stored away in the basement and brought up in sequence to reconfigure as necessary," says Jackson. "One of those pieces is a hydraulic lift that goes all the way down to the basement, so all of the pieces can be stored away in an adjacent structure and brought back up as necessary."

Besides the support spaces for the organ, an underground organ repair shop, recording, rehearsal, wardrobe and dressing spaces were also revised. And to better blend with Temple Square, the tabernacle's grounds were repaved and its planting beds restored by MGB+A of Salt Lake City.

The attention to detail paid off – the choir's verdict has been overwhelmingly positive. "Like a football team or a basketball team would say, they have a home field advantage," says Jackson. "This is their home. They love to play here and they have told us it sounds better than ever."

After a two year closure, the tabernacle reopened with a series of concerts to celebrate its revitalization and to welcome the choir back to its "home field." "Frank Lloyd Wright called the tabernacle, 'one of the architectural masterpieces of the country and perhaps the world,'" says Jackson. "The building itself and its organ are treasures in the local community, the American architectural community and the world-wide musical community, and I'd like to give my compliments to the church leaders for committing to this building, from its initial construction to its preservation and adaptation. It is a wonderful example of pioneer construction enduring and adapting throughout the years, and it is a testament to the church and the community that it stands so proud today." TB

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