By DENIS CUFF
Contra Costa Times (California)
After the 1906 earthquake and fires turned most San Francisco buildings into rubble and ash, some people hoped it would result in tough building codes to protect residents from the risk of living in a shaky state.
That didn’t happen.
It took two decades for the building industry to develop its first recommended uniform code for designing structures to withstand earthquakes and fires.
Seventy years passed before the state required all counties and cities to adopt a uniform code with a baseline of minimal quake protections.
Even though California is a world leader in earthquake protections, its codes evolved in political fits and starts, and technical trial and error.
A series of quakes stoked the changes.
“It’s the way construction has evolved since people started stacking up rocks for structure. They fall down and people figure out a better way to put them together,” said Chris Poland, a San Francisco structural engineer.
“We use our techniques and computer analysis to predict, but the only real test we have is a major earthquake.”
San Francisco’s 1906 quake provided a whopper of a test at a time when a few American cities were developing the most rudimentary of building codes.
Afterward, San Francisco civic leaders decided against making major upgrades of the city building code even though the U.S. Geological Survey concluded that poor building design contributed to the heavy losses.
San Francisco leaders worried tougher code standards could slow reconstruction.
“In the rush to rebuild, San Francisco was denied a safer future,” Philip Fradkin wrote in his 2005 book, “The Great Earthquake and Firestorms of 1906.”
Efforts to upgrade the code substantially were defeated, Fradkin wrote. “For those in charge of building ... little or nothing should be done so the city could be rebuilt as quickly and as cheaply as possible.”
Reconstruction crews filled mushy shoreline areas with earthquake rubble to build on despite scientists’ warnings that those areas were vulnerable to quake damage.
City leaders downplayed the earthquake damage to avoid scaring off loans needed to finance reconstruction.
After all, political leaders noted, most destroyed buildings were done in by fire.
At any rate, the 1906 earthquake did light scientists’ and engineers’ interest in learning how to design stronger buildings.
In 1927, a professional group called the Pacific Coast Building Officials came up with America’s first recommended uniform building code to withstand earthquakes and fires.
But cities and counties didn’t have to adopt that uniform code, even after the state in 1933 required the local agencies to adopt some building codes.
“The state and federal governments only step in when there are enough dollars and lives lost to justify it,” said Ron Hamburger, a San Francisco structural engineer who has chaired many committees recommending building code changes. “There is no political will unless there are bodies laying out there.”
Indeed, most of California’s seismic rules have been sparked by specific damage.
The state took over review of school design plans after the 1933 Long Beach earthquake, which collapsed many schools at 5:54 p.m., when few students were around. Some 120 people died in that earthquake, including five children crushed in a gymnasium.
The state asserted control over hospital reviews after a 1971 earthquake toppled a San Fernando Valley hospital, killing three people inside and 62 people elsewhere
In 1979, state lawmakers told cities and counties they would have to adopt a uniform statewide building code as a baseline safety net, but they were free to add tougher provisions.
After the 1994 Northridge quake, codes were changed to protect against a weakness shown in a common joint in steel frame buildings.
Experts caution the public might expect more protection than modern building codes can deliver.
While some people believe a modern structure built to code will escape damage in an earthquake, regulators and building officials say that is unrealistic
“The code is to provide a minimum baseline design so a building doesn’t fall with you in it,” said William Schock, president of the California Association of Building Officials. “It doesn’t guarantee that the building won’t be damaged.”
QUAKES AND RESULTING CODES
April, 18, 1906 -- San Francisco quake of magnitude 7.8 at 5:12 a.m. on a Wednesday. Few code changes.
June 29, 1925 -- Santa Barbara quake of 6.3 at 6:42 a.m. on a Monday. City adopts nation’s first municipal building code for seismic safety.
March 10, 1933 -- Long Beach quake of 6.3 at 5:54 p.m. on a Friday. State requires cities to develop building codes and issue building permits. State also takes over review of new school design.
Feb. 9, 1971 -- Sylmar quake of 6.5 at 6 a.m. on a Tuesday. State takes over control of hospital design review.
Oct. 17, 1989 -- Loma Prieta quake of 6.9 at 5:04 p.m. on a Tuesday. State orders review and retrofit of bridges.
Jan. 17,1994 -- Northridge quake of 6.7 at 4:30 a.m. on a Monday. State upgrades building codes.
Sources: California Building Standards Commission, California Seismic Safety Commission, U.S. Geological Survey.