downtown-los-angeles-at-dusk

Building Integrity: A Building’s Ability to Shake, Rattle, and Roll

Location: La Habra, California

Date: March 28, 2014

Time: 9:06 PM

Imagine this scenario. You just got off of work and are on your way home. You pull into the driveway of your home, finish listening to “#Selfie” before you turn off your car, then you get out and start walking towards the front door. All of a sudden your legs start to feel like Jell-O and you hear a low rumbling noise. You look around and see trees shaking, cars bouncing up and down, and the sky flash white and then go dark. You just experienced your first 5.1 magnitude earthquake and are wondering if that building has integrity. Welcome to my life.

As my hands shook trying to get the key in the door, I had two things in mind, check on my family and see how much damage awaited me inside. What I found was my family trying to get out of their bedroom after a bookcase had fallen in front of their bedroom door, scattered glass from the broken dishes and picture frames, and my television on the floor cushioned by my pile of dirty clothes. However, the house was still standing and aside from the rather large and newly formed cracks in the walls, the house stood blemish free. The reason being, newer buildings are more structurally sound than ever before, especially in an earthquake prone area like Los Angeles.

Downtown-LA-from-Grand-Park

Downtown L.A. from Grand Park. Photo by Gabriel Guerra.

A History Lesson

Los Angeles is not the only major city in California that suffers from earthquakes, but it’s most known for what it has done to lower the risks associated with the thunder from down under. L.A. has had its fair share of large earthquakes over the years, however, after making major changes following the Northridge earthquake of 1994, the region has seen much less damage. The 5.1 magnitude La Habra earthquake came months after the twenty year anniversary of Northridge and served as a wake up call for many. The main shock and the 150+ aftershocks put an emphasis on the Puente Hills Thrust Fault, a fault that could potentially cause immense damage to Greater Los Angeles due to its location and the concentrated populations that live above it. L.A. has some of the most earthquake resistant buildings in California, but it also has about 1,500 highly occupied buildings at risk of structural failure. Those most at risk are those that were built primarily out of concrete before 1980. Earthquake awareness and preparedness could not have come at a better time for Los Angeles as it puts a priority on developing more earthquake resistant buildings during the city’s most prime years.

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Buildings on Figueroa Street, Los Angeles. Photo by Gabriel Guerra.

Building Integrity for the Future

As more people move to the city, developers need to make sure that the building integrity are not only sustainable, but that they can stand the tests of time as well; earthquakes, winds, flooding, and zombie apocalypses. Following stricter building codes, architects are finding alternative means to make buildings more structurally sound from the use of steel plate shear walls to constructing buildings that separate from their foundations through base isolators. Skyscrapers are incorporating systems that counter the sway of the building through hydraulic pistons and slosh tanks in order to combat high winds and earthquakes that cause the structure to move in an uneasy way. The most common practice in making a building seismically sound is by using steel reinforcement on the exterior of the building as it not only supports the framework, but it can also be an aesthetically appealing attribute of the structure. Whatever they choose to use, it is expected of architects and urban planners alike to design a city that is structurally exceptional rather than just sufficient.

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Buildings near Los Angeles’ Historic Core neighborhood. Photo by Gabriel Guerra.

Reinvesting in the Future

Such practices are not only being applied to new buildings, but they are essential in the retrofitting of at risk buildings that can be found within the city. California underwent a major overhaul of its building codes in 1997, but a majority of cities such as Los Angeles still encompassed historically significant homes and complexes. So what happens with all of the buildings that are now potential liabilities for the city and its residents? Retrofitting is the practice of providing new resources to a structure that were not available when it was originally built. Through Performance Based Earthquake Engineering, retrofitting practices are utilized to identify buildings in one of four levels: Public safety, structure survivability, structure functionality, and structure unaffected. The level of public safety aims to ensure no human lives will be lost even though the building will most likely be written off as a total loss, while the level of structure survivability is focused on the need to repair a building rather than replace it following a catastrophic event. The level of structure functionality assures occupants that the building can still be used regardless of minor cracks or other damages, and the structure unaffected level secures the fact that the building will suffer no damage. While they are only predicted levels of a structure’s seismic management, they provide assurance that life will be preserved even if the building cannot be.

Our response to natural disasters is often lacking, mainly due to the fact that we as a society are unprepared. We get so wrapped up in our day to day lives that we think such a catastrophic event could never happen to us. Through the incorporation of preventative measures into new buildings and by retrofitting older buildings to encompass the same qualities, we can ensure that over the years, earthquakes and other natural disasters will come as less of a surprise to us.

Feeling earthquakes was part of growing up, and also preparing for them: doing earthquake drills, or having earthquake supplies. The looming feeling was part of my life. My experience of earthquakes has always been more the fear of them, or the possibility.

-Karen Thompson Walker, Author

Feature Image: Los Angeles at dusk. Photo by Gabriel Guerra.

About The Author

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As a recent transplant in the city of Los Angeles, I have a way of looking at the city that natives themselves have not been able to. My focus in school is urban planning, environmental science, sustainable design, and rooftop gardens. Follow me on my adventures throughout L.A. to see all that this sustainable city has to offer.