By Shawn Kyles
In southern California it is vital to consider the dangers of earthquakes. In order to prevent or minimize damage to a home during an earthquake, and prevent the possibility of the need for foundation replacement, it is important to consider earthquake retrofitting.
About fifty years ago, buildings were mainly designed architecturally to endure one type of load, namely gravity. That means an up-and-down pressure or motion. In the recent years, however, it has been more widely recognized that most earthquakes create pressures on a structure moving from side to side. This creates, as engineers define it, a lateral load. Thus, older buildings that were originally designed only to adequately support gravity loads may actually collapse as a result of the lateral pressure of an earthquake. As a result, during an earthquake, older warehouses or houses that are built out of brick and have thick walls and massive beams can be reduced to debris in seconds. But buildings that were built from wood frame are generally much more able to withstand lateral forces, because of their flexibility and the fact that they are able to move from side to side or up and down.
The idea of seismic retrofitting is not really complicated. A foundation expert bolts the house to the foundation, adds plywood to support any structurally weak walls, and then uses special hardware to bind those components together. The idea here is to transfer forces of the earthquake to the foundation. A building that is properly joined together and then secured firmly to its foundation is less likely to collapse or slip off of its foundation.
Engineers and seismologists agree that seismic retrofitting, when done properly, will significantly reduce potential destruction from a major earthquake. And it will help avoid the chances of needing foundation replacement. The concept may be simple, but rendering it is very technical. This is not an area of “do-it-yourself.” It is best to hire a contractor who is an expert in earthquake retrofitting, and foundation repair and construction. A competent foundation repair expert will know which areas need to be bolted and strengthened.
The most optimum thing you can do as the homeowner is obtain a better understanding of the retrofit process so that you can ask appropriate questions and select the contractor that will perform the best job for you.
The fact is, that for majority of people the home represents the greatest part of a family’s net worth (though that value has taken a hit in recent years). Most earthquake probability studies indicate that much of this net worth may be in danger if the home is not retrofitted properly.
Most foundation repair contractors will offer a foundation inspection, so you can find out the status of your home and its foundation and find greater peace of mind.