What is the remedy if a building is a soft-story?
A soft story retrofit involves strengthening and stiffening the first story, so it does not “pancake” or collapse. The retrofit might involve the addition of steel moment frames, shear walls, diagonal bracing, or fusing systems.
Why are soft story buildings in danger during an earthquake?
The soft-story apartment buildings with carports under them are more susceptible to collapse in an earthquake because the heavier upper floors are resting on a weaker ground floor. The wood and cement columns cannot support the entire buildings during violent shaking.
Is my building a soft story building?
A soft story building is any multi-story building in which one or more floors have windows, wide doors, large unobstructed commercial spaces, or other openings in places where a shear wall would normally be required for stability as a matter of earthquake engineering.
What is a soft-story retrofit?
What is a soft-story retrofit? A soft-story retrofit simply adds to and reinforces the structure of the building so it can hold up much better in an earthquake. The main goal is to make sure the building is still standing after an earthquake hits and ensure the safety of everyone in and around the building.
How does a frame with soft storey behave under earthquake?
During an earthquake motion, the soft story behavior is based on the criteria that the ground motion will look for all possible weakness in the structure. This floor hence has a lower structural stiffness compared to the above floor. It represents a vertical symmetry.
Are soft story buildings safe?
Soft story buildings are vulnerable to collapse in a moderate to severe earthquake in a phenomenon known as soft story collapse. As of 2009, few such buildings in the area had undergone the relatively inexpensive seismic retrofit to correct the condition.
Will my apartment building collapse in an earthquake?
This type of apartment building design is prone to structural failure and collapse during earthquakes if not built to modern building code. Such buildings collapsed in the 1989 Loma Prieta earthquake and the 1994 Northridge earthquake, including one apartment building where 16 people died.
How much does soft-story retrofit cost?
Through the Community Action Plan for Seismic Safety (CAPSS) analysis, it is believed that these retrofits will cost between $60,000 and $130,000, depending on the building size.
How much is a soft-story retrofit?
In what manner is the Behaviour of a soft storey construction likely to be different from a regular construction in the event of an earthquake?
Soft story configuration in structures is a type of construction where any one story of the building is more flexible (less stiff) when compared with other floors. This may be located at the bottom, or at any intermediate points, where the floor above or below it may be stiffer compared to itself.
What is a soft story building?
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.
Are San Francisco’s soft story buildings in danger of collapse?
In the San Francisco Bay Area, a region notorious for its earthquakes, an estimated one in six structures are soft story buildings, which means that many neighborhoods could experience catastrophic building collapses in a major earthquake if property owners refuse to retrofit.
What happens to soft floors during an earthquake?
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.
Why are parking garages considered soft stories?
Parking garages are typically soft stories. 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.