Could L.A.’s High-Rise Buildings Sustain a Large Earthquake? You Might Be Surprised …

Posted October 5, 2021, under Blog

Downtown Los Angeles is made up of a variety of high-rise buildings. While you’d think these structures were built to withstand a large earthquake … you’d be wrong.

Two of the largest buildings in L.A. were built in the 1970s. Originally referred to as the ARCO towers, these structures are now the National Bank and Paul Hastings towers, each 52-stories high.

The towers were constructed using welded steel moment-frame, a type of construction that was extremely popular in the 1960s-1990s and believed to be “earthquake proof.”

Unfortunately, when the 1994 Northridge earthquake hit, we learned that not only were these structures not earthquake proof, they’re at-risk of collapse with high-intensity shaking.

Despite the fact that Southern California has several large, active fault lines that run through downtown Los Angeles and other densely populated areas in and around the city, these buildings have yet to be retrofitted for earthquakes. In fact, little has been done in Los Angeles regarding the retrofitting of high-rise welded steel moment-frame buildings.

Unfortunately, in Los Angeles and throughout the country, building codes and regulations are only changed after major disaster strikes.

For example, in 1933 a 6.4 magnitude earthquake killed 120 people in Long Beach. Some 100 plus schools in the area were damaged and 70 were completely destroyed. If the quake had occurred during school hours, thousands of children could have been injured or even killed. As a result, the city passed the Field Act which requires schools to maintain certain levels of earthquake-resistant construction.

The same situation occurred in the San Fernando Valley, when a 6.6 quake in 1971 led to the collapse of a hospital which killed 64 people. This paved the way for major changes in hospital building codes. And now, decades later, there are mandatory retrofit programs in place working to strengthen these older concrete buildings.

During the 1994 Northridge earthquake, we saw the destruction of a number of soft story apartment buildings in Los Angeles. While a mandatory retrofit is in effect for these structures, some 4,000 plus buildings still need to be retrofitted.

The first signs that steel-moment frame buildings were vulnerable to earthquakes was after the 1971 San Fernando quake, which created cracking in the two ARCO towers.

The buildings were still being constructed at the time, and no major changes to the building codes were made. The cracks were sealed, and they carried on with the work.

This same cracking happened again after the Northridge quake, with reports of serious damage to steel-moment frame buildings coming from all over L.A.

While the city stopped using steel-moment frame construction for high-rise structures after the Northridge earthquake, thousands of these types of buildings remain untouched and in use throughout Los Angeles.

As of now, the city of L.A. is doing “nothing” to address these issues, according to Mayor Eric Garcetti.

A 2008 report, called the ShakeOut, examined the fallout from a hypothetical 7.8 magnitude earthquake on the San Andreas fault, and it showed the collapse of 5 steel-moment frame buildings in Los Angeles.

According to the ShakeOut report, “The southern San Andreas Fault has generated earthquakes of ShakeOut size on average every 150 years — and on a portion of the fault that ruptures in the ShakeOut Scenario, the last earthquake happened more than 300 years ago.”

Meaning – we’re very, very past due to another major earthquake on the San Andreas fault.

If you live in Los Angeles, it’s important to be proactive about earthquake preparation and safety. One of the most effective ways to protect yourself, your loved ones, and your property is to have your home retrofitted for earthquakes.

If you think your home is in need of foundation repair, foundation replacement and/or earthquake retrofitting, contact Julian Construction today and we will send one of our foundation specialists out to conduct a free, thorough inspection with a quote for repair.

We have extensive experience serving our Los Angeles community and nearby regions. In fact, Julian Construction has inspected over 30,000 structures in the area!

Julian Construction was formed in 1994 and our focus has always been on building foundations, doing foundation repair and replacement, earthquake retrofitting, and house leveling.

When you work with Julian Construction, you get the principles of the company and the workers of Julian Construction under your home.

And in order to keep foundation repair affordable for our customers, we offer a price guarantee — because we know our quote for repair will represent your very best value.

Give us a call at (323) 733-3377 to schedule your free inspection or complete the inspection request form.

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