Rising to the challenge of perfection

Concrete Construction, August, 2002 by William D. Palmer, Jr.

Past the 25,000-pound bronze doors of Our Lady of the Angels Cathedral in Los Angeles, the entrance corridor rises at a pitch of 95 feet per quarter mile. Cardinal Roger Mahony felt that through the effort needed to climb this "mountain" to the cathedral's nave, the penitent would shed the cares of the world and become ready to receive the word of God. Building this huge concrete structure required the construction team to undergo a similar change of mind. "We had to convince 215 guys," says Bob Wiegman, concrete general superintendent for general contractor Morley Construction, "that perfect, at least what they had always thought of as perfect, wasn't good enough for this job."

Cardinal Mahony set the tone for construction. He wanted a new cathedral that would rival the great cathedrals of Europe--a world-class church that would stand for 5 centuries to inspire the faithful and bring faith to nonbelievers. From Day One he showed by example that the only way to build such a monumental structure was to work as a team--a true team, not the loose almost oppositional team often found on a large project. The cardinal assembled a core team, which included design architect Jose Rafael Moneo, executive architect Leo A. Daly, structural engineer Nabih Youssef, and Morley Construction Company.

All were involved from the conceptual stage, with senior vice president Terry Dooley leading Morley's effort. In addition to being the general contractor on the project, Morley self-perfomed the concrete work and brought other experts onto the team as needed. For example, because of the design's complexity, the original design drawings were all based on a coordinate system--not very useful for building forms and positioning reinforcing steel. Morley hired architects SPF:a to convert all of the drawings to true dimensions and to incorporate information for all embedded elements. These working drawings proved invaluable to all of the trades on the job.

But the team included much more than management alone: everyone from form builders to concrete crews to material suppliers was a part of the process, imbued with a deep sense of commitment to the project. Morley divided the project into five sections and assigned production goals to the workers in each. Team barbeques were held when the goals were achieved. "When I proposed the field offices," says Dooley, "Brother Hilarian O'Connor (the archdiocese's director of construction) thought they were too big. But I foresaw a need to have enough people onsite so that we could make on-the-spot decisions." This was especially important on such a fast-track job, where construction had begun even while the design was still evolving. With all team members represented onsite, there was nowhere to hide, literally or figuratively. For much of the cathedral construction the cardinal actually lived onsite.

A high-profile job

Hard against the Hollywood Freeway, with LA's traffic zooming by, the cathedral today is quiet and magical, belying the manic activity of the previous 3 years. Though capable of seating over 3000 worshipers, it has an intimate feeling with the gauzy light that filters in through windows of thin alabaster, creating ever-changing shadows and textures on the terra-cotta-colored concrete.

On a site that includes the cardinal's home, an educational center, a 2 1/2-acre outdoor plaza, a 156-foot-tall campanile (or bell tower), and a 600-car parking structure, the cathedral itself is by far the dominant structure both in quality and size. Almost completely concrete, except for steel truss girders spanning the nave, the cathedral took nearly 3 years to complete.

Cardinal Mahony insisted that this building had to not simply survive for 500 years but stay dependably in service. And since this is California, that meant that earthquake forces had to be foremost in the designers' minds--especially since Los Angeles' previous cathedral, St. Vibiana, had been seriously damaged by the 1994 Northridge earthquake.

To resist seismic forces on a structure as stiff as a massive concrete building, base isolation is an obvious choice. Structural engineer Youssef designed a system with 149 elastomeric base isolators--resembling 40-inch-diameter hockey pucks--to support the entire 125 million pounds of the cathedral. These isolators will moderate the forces of an earthquake by 75%, allowing the building to move as much as 27 inches in any direction. To accommodate this movement, there is a 28-inch-wide dry moat around the cathedral. "Without the base isolation system," says Dooley, "many of the concrete walls would be expected to crack in an earthquake. That might be repairable but would be an aesthetic disaster. Besides, the cardinal doesn't simply want the building to survive. When I asked what he would like to see happen on the evening after an earthquake, he said, `I want it to be a place of refuge for the displaced and homeless.'"

A job about walls

"This was a job about walls," says Morley's David Selna, project manager for the concrete work. "Most concrete jobs are about columns and decks; this one was about complex walls, and all of the work was done from jump platforms." Rising as high as 130 feet, the rosy-tan-colored, lightly sandblasted concrete is intended to evoke the feel of California's Spanish missions.