When Marquette University started planning for the construction of Zilber Hall, the welcoming facility for prospective students and their parents, precast concrete inlaid with brick offered a structure with the right mix of traditional and contemporary appeal.
By Deborah R. Huso
One of the greatest challenges of institutional architecture, particularly when working in a historic university setting, is making sure that new buildings complement older ones – no small feat when contending with structures spanning more than 100 years. At Marquette University in Milwaukee, however, architectural precast concrete has come to the rescue on more than one occasion. Most recently, precast was used for the construction of the university’s Student Services Building, Zilber Hall, which opened for business last fall.
Blending with existing architecture
“Because of where the building is located on Wisconsin Avenue right across the street from some of the oldest buildings on campus – all of them brick – we really wanted it to fit in,” says Tim Hansmann, Zilber Hall’s design architect with The Kubala Washatko Architects. Zilber Hall is also one of the focal points of the campus with 12 college departments occupying space there, including the admissions department and the president’s office. “The university wanted the building to be inviting, welcoming and dignified but not ostentatious,” Hansmann adds. Because it serves as the Student Services Building, Zilber Hall is the first place on campus that prospective students and parents visit.
“The design was a challenge because of the historic context surrounding the building site,” adds Tom Ganey, university architect. “We wanted it to blend but have its own look.”
To accomplish a warm and welcoming space, the four-story, 128,000-ft2 (11,900 m2) hall features an open plaza on the side facing the historic Church of the Gesu and a long, light-filled gallery along the building’s front, where students can walk in winter to avoid the weather. The hall is one block long and features a punched-opening look that is at once traditional in style with a bit of modern flair in the use of exterior aluminum sun shades over the windows. The shades help control glare and the amount of sunlight coming into the structure, and accent the “in-and-out” detailing of the facade.
Mark Tredo, project manager for Opus North Corp., the general contractor for Zilber Hall, says there was never any question that the new building would feature precast architectural panels for its facade. For the building’s structural framing, the design team considered structural precast columns and beams and poured-in-place concrete floors but ultimately decided on a steel frame for the sake of cost and speed. “For a cast-in-place concrete-framed structure, you need to get to six or eight stories to really get the economy,” Tredo points out. And since Zilber Hall’s outer precast panels are gravity supported, they don’t require significant additional support.
Established history of precast solutions
Zilber Hall is far from being the first structure at Marquette University that takes advantage of the versatility of architectural precast cladding. Three other campus landmarks feature precast cladding: Raynor Library; Eckstein Hall, the newly opened law school; and the Al McGuire Center, a basketball and training facility. Two parking garages on campus were also built using precast. One of the parking garages, now about 15 years old, was the first campus project featuring inlaid brick in concrete. At the time, the brickwork was done in the field (after precast erection), not in the plant.
“There’s definitely been an evolution in process,” says Julie Ledger, director of project management with Opus North Corp. Opus North Corp. has worked on all of the university’s precast buildings, including the Discovery Learning Complex, a new building for the College of Engineering that is currently under construction.
“It’s been a journey,” says Tom Kennedy, vice president and general manager of project management for Opus North. “In the institutional world, they’re looking at matching 100-year-old buildings with new construction.” Brick-embedded architectural precast panels have made it happen. “Everybody likes the aesthetic we’re getting from the product.”
“The university has tested precast, and they’re happy with it,” adds Hansmann. “They especially like how quickly it goes up.”
And given the long Milwaukee winters, precast represents a particular advantage in keeping construction going year-round. “These panels can be formed in any kind of weather,” Hansmann points out. Construction of Zilber Hall began in August 2008, with much of the work on the precast panels occurring in the factory throughout Milwaukee’s harsh winter weather. Panel fabrication took about three months.
Just the right brick
It was important for the design team to find a brick finish that blended with the many existing masonry buildings on campus. “The university wanted the color and texture of the brick to fit the landscape,” says John Bisswumm, president of International Concrete Products Inc., the project precast manufacturer. “They especially wanted the building to match Raynor Library.”
The advantage of all these projects in which Opus North has been involved is that they have helped the university establish “a brick family,” as Ledger calls it, so that all the precast-clad structures with inlaid brick complement one another when it comes to color and texture.
The design team ultimately decided to use the same brick employed in gateway elements on Raynor Library. International Concrete then cast two sample panels for the university to review on campus at the building’s actual location. “One of the benefits of this system is that you’re using real brick,” says Tredo, “so that makes it easier to blend into the brick that’s already on campus.”
To create the high-end look of brick-embedded precast panels, International Concrete essentially cut the bricks in half, thus getting twice as much surface area out of one brick, placed the bricks in a form, and then poured concrete backing over it with the concrete creating mortar joints in the brick. “Basically the bricks are handset individually, and the concrete is poured in behind them,” Bisswumm explains. It’s more labor intensive than panels made exclusively of concrete but a lot less complex (and at less cost) than traditional masonry, where in addition to labor and material
expenses, one has to contend with the constraints of weather as well as the cost of scaffolding.
Bisswumm says he believes the precast panels with inlaid brick have greater structural integrity than brick as well. “The mortar joints here are being formed with 5,000 psi (35 MPa) concrete,” he points out. “There will be no need to replace mortar joints down the line. The only thing you might have to replace is caulking.” The results are durable finish architecture that mimics expensive brick masonry. And precast provided a design advantage for the architects, as it allowed for the distinctive banding look around the building’s entrances, where the faux brickwork harmonizes with horizontal faux masonry features for a sophisticated, upscale look for this important campus gateway structure.
Construction constraints and opportunities
The architectural precast panels for Zilber Hall are 8-in (205-mm) thick, self-supporting and attached to a steel frame. The largest panel is about 15-ft (4.6 m) wide and 40-ft (12-m) long. The size of the panels, of which there were 542 in about 30 different shapes and sizes, was limited by installation constraints in a tight construction space in downtown Milwaukee. Construction was ongoing right alongside busy Wisconsin Avenue with 10,000 students passing the site daily. The structure was also being built within 4 ft (1.2 m) of adjacent buildings. Because precast wall panels arrived on the site just-in-time for erection, there were no problematic space requirements for extra construction equipment or material laydown.
The most challenging part of the project, in Tredo’s view, were the details of the joints and corners. “It’s always tricky to make them look like a traditional building,” he says, pointing out that caulking of joints is key both for structural integrity and the appearance of the facade. “When the brick returns on a corner around a window, you have to figure out where to stop the brick, so you can get a clean caulk joint at the window,” he explains. “You don’t want the brick returning beyond the window frame, as you want the glazing to butt up flush against the precast wall panel and not the brick inlay.”
Architect’s first experience with precast’s advantages
International Concrete was able to create about 10 to 12 panels from each form before having to re-create the form, so Hansmann says he used that knowledge as a benchmark for how much variety he could employ in the size and design of different panels.
Hansmann had never worked with precast panels with inlaid brick prior to the Zilber Hall project, so he admits he had to overcome a learning curve. Collaboration was key. Opus North helped Hansmann understand precast fabrication details and its architectural flexibility before he began designing the building.
“If we had gone much higher than four stories,” says Hansmann, “we would have needed trickier connectors.” The attachment of the panels was a fairly standard process using a dowel system. The builders essentially drilled a dowel into the foundation wall at grade, slid the panel on top of the dowel and then (above the ground story) used wall plate and bracket attachments to the steel framing. The building team set 12 to 15 panels per day over the course of two months. “Because it’s a gravity-supported system, International Concrete was able to maximize the height of the precast with the gravity load,” explains Kennedy.
“We were able to get the look of costly inlaid stone pieces, striping and unique architectural features pretty easily and in the same form,” Hansmann points out. If the design-build team had been working with traditional brick masonry, they would have had to order specialty precast pieces to create these extra architectural details.
Teamwork is critical
Zilber Hall was completed by November 2009, following an 18-month construction cycle. Total cost of construction was about $28 million. Zilber Hall recently received LEED certification from the U.S. Green Building Council. All the materials for the precast portion of the building were acquired regionally, including the aggregate, brick, sand and steel. It’s also important for LEED certification that structure operating costs be reduced, which is almost always the case with precast, both in terms of maintenance and energy efficiency. Zilber Hall is the second building on Marquette’s campus to receive certification. Opus North is expecting LEED Silver certification for the newly constructed law school as well as for the College of Engineering currently under construction.
Ganey says collaboration was essential to the project’s success. “I insisted that designers meet and work with the precaster before starting design,” he explains. “The precaster coached the architect on how the product works, including how they could do joints and detailing.” Tredo says having the site prepped well in advance of installation as well as having the right crane for the job makes a huge impact on construction speed and success. Ledger agrees, adding that the relationship among International Concrete, Kubala Washatko Architects and Opus North was critical, too. “The collaboration ahead of time made all the difference and mitigated issues we could have had on the job site,” she points out.
“Having craftsmen talk to the architect is critical to success,” Ganey says. “Then designers understand how far they can push the design. You get a far better product when you have a team environment.”
Deborah Huso is a freelance writer who covers home design and restoration, sustainable building and design, and home construction.