Does Your Manufactured Home have Earthquake Bracing?

Woman hands covering a model house with bubble wrap

California, specifically the Bay Area, felt quite a rumble in January. The New Year started with a 4.4 magnitude in Berkeley along the Hayward Fault, which lasted about 10 seconds. An estimated 9.8 million people in the Bay Area felt the aftershocks of the quake, leaving them to question whether they are ready for when the “big” earthquake hits California.

The quake was a reminder that there is a one-in-three chance that a 6.7 or greater earthquake will hit the Bay Area in the next 30 years, according to the United States Geological Survey.

While the state of California’s Residential Mitigation Program offered grants of up to $3,000 for seismic retrofits of older homes, one of the most asked questions regarding manufactured homes are whether they are safe from earthquakes.

“Manufactured homes fair very well during earthquakes,” said Ara Sarkisian, a partner in Alliance Manufactured Homes. “They are built with a high percentage of shear walls, which offers great structural support during any shaking or rattling from an earthquake.”

Compared to on-site built homes, manufactured homes are lighter in general, an advantage in the context of earthquake ground motion, as seismic forces are proportional to the weight of architectural structures. These factory-built homes are built to resist the severe forces and shaking when transported on a permanent chassis from factory to site. The seismic performance of manufactured homes depends largely on the condition of the foundation and particularly on the connections between the home and the foundation, in accordance with Arash Nasseri, Ph.D. and Ehsan Kianirad, Ph.D. of ‎AIR Worldwide.

With Pier Approval by the State of California Department of Housing and Community Development, manufactured homes are installed onto a series of steel support piers, one of the most used earthquake restraint bracing systems (ERBS).

piers1
Figure 1. A display model of a manufactured home supported by multiple standard piers.

The piers offer structural foundation and seismic bracing for any lateral forces caused by earthquakes. It is also important to secure the piers to their footings and main beams of the home, as shown below (Fig 2). These connections will prevent the home from jumping off the pier or footing during an earthquake.

piers
Figure 2. Secure piers to their footings and to the main beams of the home.

Alliance Manufactured Homes Installations has installed 75% of the new manufactured homes in the Greater Bay Area, accredited with over 5,000 new home installations.

For more information on the safety of our manufactured homes, call (888) 874-8692 to speak with an agent today!

Cabanatuan, Michael et al. No damage reported as 4.4 Berkeley quake rocks Bay Area. SFGate. 4 Jan 2018. Web. 26 Jan 2018. http://www.sfgate.com/bayarea/article/No-damage-reported-as-4-4-Berkeley-quake-rocks-12472837.php.
Lin II, Rong-Gong and Serna, Joseph. Bay Area earthquake rattled 9.8 million people — and offers a preview of something much worse. LA Times. 4 Jan 2018. Web. 26 Jan 2018. http://www.latimes.com/local/lanow/la-me-ln-earthquake-bay-area-20180104-story.html.
Lochner, Tom. Here are the Bay Area communities eligible for state earthquake retrofit grants. East Bay Times. 23 Jan 2018. Web. 26 Jan 2018. http://www.eastbaytimes.com/2018/01/23/homeowners-in-several-east-bay-communities-eligible-for-state-earthquake-retrofit-grants.
Minimizing damage and repair costs to manufactured homes during an earthquake. U.S. Department of Housing and Urban Development. Web. 26 Jan 2018. http://www.huduser.gov/publications/pdf/pdrbrch.pdf.
Nasseri, Arash and Kianirad, Ehsan. Understanding the Seismic Vulnerability of Manufactured Homes. AIR Worldwide. 23 Oct 2017. Web. 26 Jan 2018. http://www.air-worldwide.com/Publications/AIR-Currents/2017/Understanding-the-Seismic-Vulnerability-of-Manufactured-Homes.

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