Report Warns of L.A. Building Collapses


From factories to residential high-rises, more than 1,000 older concrete buildings across the Los Angeles skyline are in danger of collapse should a major earthquake hit the area, according to a new report.

At least five percent, or 50, of those buildings would be completely destroyed, exposing thousands to injury or death if, and when, the next large tremor occurs, suggests the new analysis conducted by the Los Angeles Times.

The report specifically focused on Los Angeles concrete buildings constructed before the mid-1970s that are vulnerable to the sideways movement characteristic of a major quake. According to the Times, these buildings don’t have enough steel reinforcing bars to hold concrete columns in place.

Concrete structures scattered across the country also face similar seismic dangers, the newspaper reported.

The news agency noted that while a few of the concrete buildings studied have been retrofitted, building owners have generally opposed retrofitting the structures, citing cost concerns.

City Declines Action

City action is deemed necessary in order to retrofit the buildings to make them safe, the Times suggested.

Los Angeles city officials have been aware of the risks these concrete buildings pose for at least four decades, but have refused to enact mandatory seismic retrofit codes, according to the article.

Current codes governing retrofitting are voluntary, the report said.

City officials have also rejected calls to even develop a list of concrete buildings most at risk, the Times reported.

List Compiled

Scientists have made their own list, but did not feel comfortable sharing that information with the Los Angeles Times due to the potential for legal action from building owners, the newspaper said.

On the other hand, the team of University of California Berkeley engineers told the news bureau that they would likely share their inventory with Los Angeles city officials if a copy is requested.

Earthquake damage
National Geophysical Data Center

Concrete structures in Sylmar, CA, collapsed during the San Fernando earthquake in February 1971, the report said. The Olive View Hospital (pictured), which had just opened and was built under stricter codes, killed three people when it collapsed.

UC Berkeley engineering professor Jack Moehle said his team had identified 1,500 potential vulnerable concrete buildings in Los Angeles through public records and the team's own walking survey, the report said.

The list was reportedly a “first step” in the process, as more thorough examination of each building would be needed to determine if the buildings needed strengthening.

‘Time is Running Out’

“Seismologists and engineers say time is running out to fix dangerous concrete buildings,” according to the report.

“If the Big One hits the San Andreas fault—and scientists say it's long overdue—seismic waves would cascade into downtown Los Angeles at a magnitude not felt since 1857,” the article said.

Portions of the fault line are capable of a magnitude 8.1 earthquake, reports relate.

“Another alarming scenario is a huge temblor striking directly underneath Hollywood or the Westside. More than 300 faults crisscross the L.A. Basin,” according to the Times.

The report further highlighted recent earthquakes that have sent concrete structures toppling, such as the 2011 earthquake in Christchurch, New Zealand. That quake collapsed two concrete office towers, killing 133 people.

The 1995 Kobe, Japan, quake was also mentioned. Many of the 6,000 people killed in that disaster were in concrete buildings, the Times reported.

"We know darn well that if a bunch of people die, there will be lots of stories, lots of reports, things will change," Thomas Heaton, director of Caltech's Earthquake Engineering Research Laboratory told the Times.

"But the question is, do we have to have lots of people die in order to make this change?"


Tagged categories: Building codes; Concrete; Construction; Disasters; Health and safety; Historic Structures; Maintenance + Renovation; Rebar; Retrofits

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