Earthquakes are considered a part of life for many of us, certainly for those living in California, but also for those living in Washington, Oregon, and even Nevada. And those of us who make mobile homes a part of everyday life should pay just as much attention to earthquake safety as anyone else. Take the 1994 Northridge Earthquake for a recent example.
The Northridge Earthquake provided an opportunity to see first hand the effects that a major earthquake event has on nearby mobile home structures. This quake struck in close proximity to several mobile home communities located in the San Fernando Valley. Damage to the homes was extensive and costly. Why did mobile homes suffer greater damage, on average, than nearby frame built homes? The answer: a large majority of mobile homes in the area were mounted on piers.
Most mobile homes are mounted on a system of piers, the most widely
used method of providing a foundation for mobile homes. These piers are typically metal tripods or concrete blocks that are positioned below the steel chassis, or undercarriage, of the mobile home. The piers are adjusted and leveled so that the mobile home itself rests in a level position on top of the piers. Once this is completed, the mobile home will be positioned approximately 24 to 36 inches above the ground. Utility hookups for water, sewage, and gas are then attached underneath the mobile home.
This is an effective method of installing mobile homes. However, it is a less than desirable arrangement should a major seismic event strike in close proximity. The piers, which are not typically secured to the ground, will give way when strong shaking motion occurs. This, in turn, causes the mobile home to drop 24 to 36 inches before striking the ground. Such an impact can bend the steel chassis beneath the home, sever and damage the utility connections, and cause the piers to pierce through the flooring of the mobile home. The contents of the home are scattered and damaged, and structures connected to the home, such as carports or patio
decks and awnings, can be torn away from the main structure.
rather simple mechanism can prevent this scenario from happening - an Earthquake Restraint Bracing System (ERBS). These systems are manufactured and sold by several companies, and in California, must be certified by the Department of Housing and Community Development. The concept is a simple one. The ERBS system is made up of two strong crossbeams underneath the mobile home structure that are supported by wide footings. In the event of an earthquake, if the individual piers give way, the crossbeams of the ERBS will hold the mobile home in place in its upright position.
We encourage all mobile home owners in earthquake prone areas to install a certified ERBS system. It can save your home from extensive damage in an earthquake.
The California Department of Housing and Community Development publishes a list of companies that manufacture certified Earthquake Restraint Bracing Systems. Click here to see the list.