Dancing bricks keep sound from entering theater

August 11, 2010

A design team headed by

RoTo Architects, Los Angeles, took a new angle on an old masonry technique to keep outdoor sound from entering the La Jolla (Calif.) Playhouse’s newest theater.

Their solution: A unique masonry wall atop the building’s roof that uses age-old corbelling techniques to curve in and out, slanting nine feet out of plumb.

"We didn’t want conventional movement of brick," says Michael Rotondi, principal at RoTo Architects, who designed the 53,000-sf theater. "Brick doesn’t have to hold precise vertical lines."

Using 4x16-inch units of brick stacked one row at a time, the Building Team constructed a wall that slants first in, then out, like an hourglass. The parabolic curvature of the wall bounces sound waves out in multiple directions, rather than directly into the main wall of the building.

The curving wall, measuring about 50 feet in height, 50 feet in width, and 70 feet in depth, spans the roof of the $15 million Sheila and Hughes Potiker Theater, a black box that seats up to 450 in the new Joan and Irwin Jacobs Center; it is the third playhouse building on the University of California San Diego campus.

Rotondi selected brick for both the slanting rooftop wall and the main structure primarily for its heftiness, which dampens vibration from sound waves hitting it and reduces the need for additional sound absorption material.

The wall stays upright through a simple balancing act: after it leans in one direction, part of the wall leans back in the other direction to distribute the weight evenly. "It’s like having different body parts lean in different directions at the same time," says Rotondi.

To reinforce the structure, two steel rods, three-fourths of an inch in diameter, cut through each block.

Kris Specht, senior superintendent at general contractor Rudolph and Sletten, Redwood City, Calif., created a four-foot mockup that was used for reference during construction.

"To control the lean, we used a straight pole at each corner and tilted the pole to the exact coordinate, and then built the wall to match the pole," says Specht. "The masons nailed the model to the pallet next to the wall so they could count the courses of plywood and see where their next point should be."

RoTo Architects used a similar corbelling technique in designing the new 110,000-sf art and architecture building at Prairie View (Texas) A&M University, but supported the walls with a steel-stud backing.

"We wanted the bricks to dance and sometimes become weightless and fluid, attributes not usually associated with this material," said Rotondi.

In both cases, says Rotondi, he wanted to design a structure that would allow craftsmen to use their often untapped skills. "People have more skill than they’re asked to use," he said. "Normally, they’re given tasks that are too conventional." Although the contractors at first balked at the complexity of the masonry work, Rotondi was able to convince them of the viability of the projects. BDC

         
 

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