WCF Corporate Office Tower
Building will provide optimum safety, immediate occupancy after seismic event
The building was designed to achieve some unique performance criteria, including immediate occupancy for a-once-in-1,000-year event, and life safety for a once-in-a-2,500-year event. Force levels are 3.5 times greater than a typical office building, at an overall cost of just 3% more than a normal structural system.
Terry Wright,an executive vice president with Jacobsen Construction Co. of Salt Lake City, doesn’t mince words when describing the toughness of Heather Talenah, project manager for Jacobsen on the new $48-million Worker’s Compensation Fund Corporate Office Tower at Towne Ridge Parkway in Sandy, Utah.
|SidePlate technology was incorporated into the structural design of the new Worker’s Compensation Fund Corporate Office Tower in Sandy, Utah. (All photos by B. Fullmer)
“She eats nails for breakfast,” Wright says. “You have to be tough to be a project manager in the construction industry, and she certainly is that.”
Talenah laughs about Wright’s description of her.
“I think that comment means I’m pretty tough, as in firm but fair, is how I like to view it,” says Talenah, a Minnesota native and 20-year construction industry veteran who was hired by Wright five years ago to manage the Zion’s Bank Tower re-skin project in downtown Salt Lake. “In construction, with potential hazards all around, you’ve got to be firm in your goals and priorities every minute and not compromise. But I think Terry really hired me because I ride a Harley.”
Wright’s “eats-nails-for-breakfast” comment is also notable because the WCF project Talenah is managing has a unique steel aspect to it. The structural system on the six-story, 198,417-sq-ft building incorporates SidePlate technology, one of only a couple of projects in the Intermountain region to utilize such a system, according to structural engineer Paul McMullen of Salt Lake-based Dunn Associates Inc.
McMullen says the SidePlate system was used because the owner wanted a building that could be immediately occupied after a major seismic event.
“It’s the most robust, highest-capacity connection for a blast or progressive collapse incident,” says McMullen, a principal with Dunn Associates who served as project manager on this job. “WCF desired a building that was immediately usable after a large seismic event. It was, and still is, of concern to them that they are able to provide services to their clients continuously. To satisfy this goal, we looked at a variety of seismic performance levels and the costs associated with them.”
McMullen says that with input from Jacobsen on the cost, the design team was able to arrive at the following performance criteria: Immediate occupancy for a once-in-1,000-year event; and life safety for a once-in-2,500-year event.
“The force levels are 3.5 times higher than a typical office building,” McMullen says. “We designed a building that will work through, and after, a major seismic event – it was critical that (WCF’s) business is not interrupted. Secondly, it only cost them about 3% more than a normal structural system.”
He adds that for the lateral system, the design basis was ASCE 41 Seismic Rehabilitation for Existing Buildings. The IBC 2006 and associated material codes do not provide design criteria for performance levels other than that identified above.
“To our knowledge, this is the first time ASCE 41 was applied to the design of new buildings in Utah,” McMullen says. It has been used on 20 or 30 buildings in California.”
|This interestingly-shaped, curved steel structure at the top of the building highlights some of the architectural detail of the WCF project. (below) A view of a SidePlate connection.
Lateral forces in the building are resisted by a dual concrete shear wall core and perimeter special steel moment frame. Another advantage is that the special concrete shear wall reduced the steel column and beam tonnage to below 400 lbs per ft, so the steel was available in a timely manner. Less steel is used because the SidePlate system stiffens the joint. (Reductions in steel tonnage of 1.5-3 psf can be realized by using the SidePlate connection).
SME Steel of West Jordan, Utah, fabricated and erected all the steel on the project. SME project manager Damion Strain says it’s a unique structural-steel system.
“The major challenge for us was we had to match up the beams with the sticks because the beam stubs are embedded in the SidePlate connections,” Strain says. “The steel had to be cut in such a way that the flanges and the webs had to match up perfectly. We had to have the SidePlate pieces mill marked so we could do that.”
Strain says SME utilized 32 total crane days during the erection of the steel, with a total of 33 employees working on the project during peak construction.
“It was a challenging project, but we do a lot of those kinds of jobs all over the West,” he adds.
Aiming for LEED Gold
From a design standpoint, architect Kenney Nichols of ASWN+ of Murray, Utah, says the building – which is aiming for a LEED gold certification – will have copious amounts of natural daylighting, highlighted by a unique stone and curtain-wall system that utilizes two types of granite, along with glass manufactured by Viracon’s St. George, Utah, facility.
|Workers install part of the exterior skin, which utilizes two kinds of granite and a highly energy-efficient, low-E glass manufactured in St. George, Utah by Viracon.
“We’ve incorporated 10-ft ceilings and 10-ft window walls in an attempt to get natural daylighting into the core of the building,” Nichols says. “We’re also holding private offices off the perimeter so as not to block out daylight. The high-performance exterior glass (a bronze glass with a low-E coating) also allows in daylight, but does not contribute to heat gain.” Nichols says all mechanical equipment will be in the basement, as opposed to on the roof, which could lead to a high-tech projection system being installed on the roof for WCF marketing/advertising purposes.
Designing around the SidePlate system wasn’t overly complicated but did require some special considerations, Nichols says.
“We went to great lengths to get a ‘bullet-proof’ building,” he says. “We had to understand how the SidePlate system interfaced with the building’s skin, which required some extra clearances. The sheer size of the columns is also a little out of the ordinary, but WCF will have a building that is highly sustainable and extremely safe.”
|The WCF Corporate Office Tower is slated for completion in July 2010.
The curtain-wall system, which was designed in collaboration between Salt Lake firms Steel Encounters Inc. and Kepco+, is being prefabricated offsite, so that once onsite, the pieces can be lifted into place and assembled on the spot.
“It’s the first time we’ve used a screw spline construction process,” says Alan Mangum, project manager for Steel Encounters. “Additionally, the vertical mullions have a male-female connection, which allows us to shop fabricate in what we call ladders. We then take it to the jobsite, hook it on a crane, fly it into place and set it that way.”
Mangum says another unique aspect of the curtain-wall system is that virtually all glass on the project is an inside glaze, meaning the glass is installed from the inside of the building, with the exception of some glazing on the building’s aluminum spandrel panels.
Talenah says the building is expected to be 38% more efficient than the average office building. A three-level, 450-stall parking garage is also being constructed just north of the main structure on the 7.5-acre site.
WCF Corporate Office Tower
Cost: $48 million
Size: 6 stories; 198,417 sq ft
Completion date: July 2010
Owner: Worker’s Compensation Fund of Utah
GC: Jacobsen Construction Co., SLC
Architect: ASWN+, Murray, UT
Civil Engineer: ASWN+, Murray, UT
Electrical Engineer: BNA Consulting Engineers II, SLC
Mechanical Engineer: Van Boerum & Frank, SLC
Structural Engineer: Dunn Assoc., SLC
Key Subs: Wasatch Electric, CVE, KOH Mechanical, SME Steel, Steel Encounters Inc., KEPCO, Perry Olsen Drywall, IMS Masonry, Harper Contracting