What is a Soft Story Building?
A soft story building is a multi-story building with one or more floors which are “soft” due to structural design. These floors can be especially dangerous in earthquakes, because they cannot cope with the lateral forces caused by the swaying of the building during a quake. As a result, the soft story may fail, causing what is known as a soft story collapse. If you’ve ever seen pictures of massive damage after a major earthquake, you have probably seen a number of examples of soft story collapse, because it is one of the leading causes of damage to private residences. Soft story buildings are characterized by having a story which has a lot of open space. Parking garages, for example, are often soft stories, as are large retail spaces or floors with a lot of windows. While the unobstructed space of the soft story might be aesthetically or commercially desirable, it also means that there are less opportunities to install shear walls, specialized walls which are designed to distribute lat
A soft-story building is a structure constructed before 1991, when the California Building Code adopted enhanced earthquake design standards, which has large ground-floor openings (parking garage, store-front windows) with slender columns supporting the upper stories. Soft-story buildings are particularly likely to lean or collapse in an earthquake. Click here to learn about the City’s Soft-Story Seismic Screening Program.
