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Concrete Projects > Our Lady of the Angels Cathedral - Los Angeles, California
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Lady of the Angels Cathedral - Los Angeles, California
Third Largest Cathedral in the World, 2002
Conceived by Cardinal Roger Mahoney, this massive concrete
structure is the third largest cathedral in the world and
the first to be built in the United States in over a quarter
of a century. Cardinal Mahoney dreamed of a cathedral that
would rival any of the wonders in Europe, that would stand
for centuries and give comfort to all who entered its doors.
He believed the only way to achieve his dream was to find
people who could truly work together as a team on this immense
project, and so Mahoney carefully chose design architect Jose
Rafael Moneo, executive architect Leo A. Daly, structural
engineer Nabih Youssef and the concrete contractors from Morley
Construction Company.
First came the design problems. The original design of Our
Lady of the Angels cathedral was based on a complex coordination
system that didn't readily lend itself to building forms and
positioning reinforced steel. Because of that, the design had
to be converted to true dimensions. The new design incorporated
information for the embedded elements, making the job much easier
for everyone involved.
 Because
the cathedral was to be located in California, it was imperative
that the structure be resistant to earthquakes. To achieve this,
Youssef designed 149 elastomeric base isolators that would support
the 125 million pound building. These isolators were designed
allow the cathedral to move 27 inches in either direction, and
moderate earthquake forces by 75%. If this system was not in
place, the cement walls would likely crack during a quake.
Most concrete contractors will tell you that the majority
of jobs are about columns and decks. The cathedral was all
about the walls. Its walls are as high in some places as 130
feet, made of lightly sandblasted concrete, and vary in thickness
from one to five feet. The concrete contractors used highly
fluid concrete, poured into watertight forms in order to achieve
uniform color consistency. The corners were so sharp and perfectly
consolidated that visitors to the site thought they were precast.
Perfect was the buzzword on this project. With up to 15 ten-man
crews working simultaneously, the walls were numbered and
every detail had to be signed off on by the structural engineer
and architect before they could even be poured. And most perfect-and
challenging-of all was the 70-foot high concrete cross behind
the alter. It weighs in at almost 2 million pounds and is
supported only by the arms, which is actually a nine inches/
foot wall tied into the 17 foot deep main concrete girders.
The cathedral boasts 25,000 pound bronze doors, a steeply
pitched entrance hall, and seating capacity for 3,000. Also
on the site are an educational center, a 156 foot tall bell
tower, and a 2 ½ acre outdoor plaza. Cardinal Mahoney
resides on the grounds of the cathedral he dreamed of, planned
for, and oversaw for the three years it took to complete at
a total cost of $200 million.
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Association (TCA). Founded in 1986, the TCA is the country's largest organization
for the advancement of site-cast Tilt-Up construction, a method in which concrete
wall panels are cast on-site and tilted into place. Sustaining members of the
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