Earthquake Safety: Touring A Few Of San Diego’s Most Iconic Buildings
Monday, June 11, 2018
It doesn’t take much to draw Pat Abbott out of semi-retirement. The San Diego geologist has a flair for explaining complicated seismic topics and an overwhelming interest in earthquake safety. A recent inewsource story about an active downtown earthquake fault gave him an idea: spend a day surveying old buildings to see how they would stand up to the Big One.
Abbott had a few in mind: the County Administration Center on Pacific Highway, the century-old First Presbyterian Church on Date Street; and — San Diego’s first high-rise office building — the historic John D. Spreckels Building on Broadway.
(While traveling from one location to the next, Abbott answered earthquake-related questions people had sent to inewsource. Those videos are included throughout this story.)
For context, the San Diego City Council created a program to reduce seismic hazards in 1992. It targeted buildings with unreinforced masonry bearing walls, known as “URM” buildings. These are “widely recognized for sustaining life-hazardous damage as a result of partial or complete collapse during moderate to strong earthquakes,” according to the city’s Division of Building and Safety.
San Diego’s program required these buildings to undergo strengthening or, in some cases, a complete seismic retrofit. A list of addresses and retrofit status was published in 2004, with 24 buildings still not in compliance.
The First Presbyterian Church was on that original list. Built in 1913 of brick and mortar, it covers half a city block. Abbott, a professor emeritus at San Diego State University, said he had concerns about the building for years and always wanted to take a closer look. After a brief surveillance of the church’s exterior, we knocked on the door and were welcomed in by Riley McRae, the church administrator.
McRae took us on a brief tour of the chapel and then offered us a peek into the guts of the building. Two flights of stairs and three ladders later, we were exploring the spacious area under the roof and learning about the seismic retrofitting that’s occurred since 2004.
McRae talked about the 7.2-magnitude Easter earthquake that rocked Southern California, Arizona and Mexico in 2010. Parishioners within First Presbyterian at the time saw only a swaying chandelier, said McRae. No damage wound up occurring to the structure.
Abbott said he was “shocked” — and impressed — that the quake didn’t affect the church.
Also on Abbott’s list: the historic John D. Spreckels building on Broadway. Thirteen stories tall and built in 1927, it was San Diego’s first high-rise office building. It was first purchased by the Bank of Italy, which then became Bank of America. In 1979, the Home Federal Savings and Loan Association took it over. Then, in 1983, the building was designated as historic. Today, it’s undergoing renovations to become apartments, and its interior is closed to the public.
But the exterior caught Abbott’s attention. He pulled out a small magnifying glass to inspect the stone facade.
“There’s thin grout, or mortar, holding these pieces of rock against the front of the building,” Abbott said. “I'm sure it would have been put on at a time when people were not even thinking about earthquakes here.”
The stones would likely fall during a strong quake, he said, becoming “guillotines for anybody on the sidewalk.”
Two blocks away, on the corner of Eighth Avenue and C Street, Abbott was drawn to a one-story building housing a discount store and The Grand Castle Restaurant and Bar. Its hollow bricks were wildly popular in the 1900s — “and still are internationally,” Abbott said — because they’re heavy, and easy to manufacture and stack. But they have no reinforcement and are as easy to punch through as tissue paper, he added. These unreinforced masonry buildings are prone to collapse in a quake.
For more context on these kinds of structures, a magnitude 6.4 earthquake struck Long Beach in the early evening of March 10, 1933, destroying 70 empty school buildings. Although 120 people died, the death toll could have been in the thousands if the quake had struck during school hours.
This “supplied graphic proof that new earthquake regulations in the building code were needed,” according to the Federal Emergency Management Agency. Exactly one month later, California’s governor signed the Field Act into law. This law prevented construction of new unreinforced masonry buildings and “effectively made the State into the building department for every school constructed by local governments.”
“What is it that was illegal in 1933?” Abbott asked outside the one-story building in downtown San Diego. “Those bigger bricks,” he said, pointing to the building’s exterior walls.
The San Diego County Administration Center lies about a mile away along the waterfront. Completed in 1938 with a million dollars from Works Progress Administration funds, the building was registered as historic in 1988.
“Engineering history was made with this building,” according to the historic registration application, “when steel piling was employed to bear lateral stress 1½ times more than any earthquake emergency would require for this basically four-storied structure ...”
Abbott and I studied its original blueprints, hung along third-floor walls, and dropped in on county spokesman Michael Workman to talk about the building’s history. Workman and Abbott reminisced about quakes that left major impressions in their lives. For Workman, it was the Sylmar earthquake, which he remembered experiencing as a kid, lying in bed. He also talked about covering the Loma Prieta quake in 1989 as a reporter — and the otherworldly feeling of flying into a San Francisco devoid of lights.
Abbott left the building with no major concerns.
“I mentioned those downtown earthquake and buildings tours I used to do for the Natural History Museum,” he said. “If I led the trip now, I would be much more hard-pressed to find problem sites.”
“The good news is — things in an earthquake-sense are getting better,” he said.
I asked if the day’s tour had eased his concerns about building safety in San Diego.
“Correct,” he said.
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