Masonry Variations – From Start to Finish

Sometimes the word “classic” can be misinterpreted as “old fashioned.” To prevent building designers from making that mistake, BAC and IMI created a national exhibition to rekindle designers’ interest in masonry construction, and to keep classic masonry materials on an equal footing with new ones. That was the genesis of “Masonry Variations” at the National Building Museum in Washington D.C. launched in October 2003.

IMI Southwest Regional Training Director Keith Behrens (BAC Local 1 TX/LA) performed a low-tech, but effective, test on the brick leg mockups. “We knew we were headed in the right direction when we were unable to break them,” he says.

Guest curator Stanley Tigerman, FAIA, began the process by tapping four recognized architects, then challenging them to push the envelope of masonry design by focusing on one of these four materials: marble, brick, terrazzo and AAC.

While each material held a specific design challenge, brick proved even more demanding because of its long history, precedent, and commonality. Facing this challenge, Carlos Jimenez, of Carlos Jimenez Studio in Houston, posed the question, “Does a brick really want to be an arch?” He determined the answer was no.

His mission now began in earnest: to free brick and allow it to float. To assess the possibilities, he turned to his collaborator, IMI Southwest Regional Training Director Keith Behrens, a member of BAC Local 1 TX/LA. Their first step was to “open” the brick unit up, and look inside for the answer. That led them to use the “shells” of brick to fashion three squares, each made of reinforced and grouted brick “legs.” With the aid of the reinforcing metal framework, each square was able to pivot 360 degrees. Each masonry square was held within each other, and able to move freely.

The exhibit generated plenty of attention from the public and media, and lots of questions about how it was accomplished. The answer? Teamwork between skilled BAC craftworkers and talented designers.

For three months they tested the concept, learning several valuable lessons. First, it seemed silly to break bricks apart, only to grout them back together. Second, the grouted reinforcement system was sturdy enough to allow for rotation, but took away from the delicate concept of brick being free. So it was back to the lab – or in this case, the IMI training center in Houston.

There, Behrens discovered that if the legs were made lighter and post-tensioned without grout, the assembly would move more smoothly and help reduce deflection across the overall lengths. He also found easier ways to lay a brick pier, with the metal rods as guides, and kept the cores clean for more efficient post-tensioning. “We saw the holes in the brick as opportunities,” says Behrens.

Structural engineer John Swink, P.E., of ACME Brick Co. made a key contribution by designing an “outboard” pivot that allowed the weight to bear down, not out. Post-tensioning from the end brought greater strength and a more appealing look.

With a tight on-site construction schedule, all the installations were started off-site and assembled to varying degrees in the Museum galleries.

A reinforcing metal framework allowed each brick square to pivot 360 degrees. Post tensioning without grout made the legs lighter and more mobile.

Curious to know if masonry materials could capture light, Jimenez visited the idea of the “core.” He selected five brick profiles, which Behrens arranged into a constellation, allowing light to flood out of the floor while the brick squares moved.

All told, the brick installation took roughly six months to conceive, test, and rework, followed by three weeks of off-site construction and four on-site. The one element most responsible for their progress was the collaborative spirit that both craftworker and architect brought to the project. As IMI project coordinator Maria Viteri, AIA, notes, “When you want to make brick spin, it takes more than a concept. It takes patience, trial and error, and most of all, trust.”