The horizontal (or lateral) motion in earthquakes create the forces that can be damaging to our wood framed homes. Homes tend to fail if the connections at the foundation and in between levels is week. The sill plate can slide off of the foundation if not bolted, has minimal bolts, or does not have the proper bolts.
Some homes are built directly on concrete slabs. These houses do not have crawl spaces and foundation walls. Houses with slabs that were originally built to code will have anchor bolts or straps. However, if the house is not bolted to the slab, the home can sustain damages.
Foundation bolting implies that bolts are added to improve the connections between the wooden framing members of a building and its concrete foundation. Usually this means adding bolts through the piece of wood that lies flat on top of the foundation, referred to as the sill or mudsill, into the concrete.
Failure can also occur if the home has minimal sheer value. Studs in a wall, or framing in a floor, can act independently in an Earthquake. This can be detrimental to a structure. Sheer walls are installed by blocking all the framing and adding structural plywood to the walls. By doing this, when and if an earthquake occurs, the individual framing members are forced to move as a unit, rather then individually. This improves the chances of the structure not being rattled apart.
Crisman Inc is certified with the EBB . Earthquake Brace and Bolt Contractor. We are registered with FEMA as a EBB vendor.