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Seismic Retrofitting Multifamilies

Seismic Retrofitting Multifamilies

The US Geological Survey states that within the next thirty years, the likelihood of an earthquake of 6.7 or greater magnitude in California is 99%. No one can predict exactly when the next earthquake will occur, yet an earthquake is inevitable. Since we are statistically aware that an earthquake in California is expected to take place in the next few decades, it is within our power to make preparations for such an event.

Many people plan ahead for earthquakes by drafting an emergency response plan and buying earthquake and first aid kits. Each of these preparations is an effective way to prepare for an earthquake. Likewise in the world of business, persons or investors that have commercial real estate property need to get ready in much the same manner along with making important arrangements for their tenants and property, multi-family dwellings where whole families reside in particular.

Following the 1994 Northridge Earthquake, multifamily dwellings of wood framed construction, especially those with “soft story” construction or “tuck under” parking, incurred structural damage as evidenced by the 2,700 multi-family dwellings (including 30,000 living units) that were vacated or had significant structural damage.

The Northridge Earthquake has taught us about the intrinsic seismic risk to multi-family dwellings with soft story construction or tuck under parking. An earthquake retrofit to this type of property is gaining more popularity among investors, banks, and the government alike as such modifications are ultimately in the interest of all involved. An increasing number of buildings will be equipped and better prepared to react to an earthquake event as others continue to pursue earthquake retrofitting for buildings with soft story construction.

Rather than dealing with expensive repairs performed after an earthquake, a proactive stance would be to retrofit a property beforehand? There are numerous ways to earthquake retrofit a building with soft-story construction. The most economic way to fortify the diaphragm and shear walls is to encase them with structural grade plywood nailed to the existing wood framing, making the lateral force resisting system better. When additional reinforcement is required, steel beams and columns with concrete footings may need to be implemented to further improve the lateral resisting system.

You can discuss earthquake retrofitting with a licensed structural engineer and a licensed contractor for a summary of the retrofit scope and a rough expense. The type of mitigation measures needed to earthquake retrofit a property effectively are contingent upon the distinguishing attributes of a property, its location, age, condition of construction, parking needs, city requirements, etc…

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