Seismic retrofitting is a structural strengthening process that begins at the foundation and related to earthquake preparation and disaster mitigation. Cal-Quake Construction is a retrofitting contractor who specializes in foundations and structural strengthening.
Cal-Quake provides quality retrofits and foundation replacement or repairs to the entire state of California. As featured on: NBC Nightly News
In order to understand the seismic retrofitting process, here are some basic concepts… The majority of structures were built to withstand one type of force or load as the engineers call it — the force of gravity. That’s an up-and-down force. Unfortunately, the most damaging component of earthquake force is from side to side, producing what engineers call a lateral load. Therefore, properties that were adequately built to resist up and down forces are potential collapses under the lateral stresses of earthquakes. When dealing with conventional wood framed structure, there are three basic types of lateral failure, and as a consequence there are three different needs in seismic reinforcement. Bracing against one type of lateral failure does not protect you from the other two. That’s why a retrofitting design should be planned by a knowledgeable professional — a scatter shot approach can leave your property more vulnerable. So here’s the rundown on the three types of lateral failure.
In California, there is an earthquake hazard disclosure law requiring the seller to disclose to the buyer at the time of sale the existence of certain known earthquake hazards, such as lack of bolting, existence of cripple walls with no shear paneling, hot water heaters that are not properly strapped, etc.. One of the conditions required to be disclosed as a hazard is the existence of a “soft story” condition. Visualize two dominoes standing on their small ends. Load four or five bricks on the dominoes with no difficulty because the dominoes are strong enough to carry the load, or downward force. But, if you go to the side of the dominoes and apply a tiny shear force: a shake or with even a breath; the whole thing will come crashing down…
We make certain to consult our structural engineers to address the specifics of your particular structure.