What is a soft-story structure?
A soft story building is a 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 design.
What is soft storey effect?
The term “soft-story” refers to one level of a building that is significantly more flexible or weak in lateral load resistance than the stories above it and the floors or the foundation below it (70% or greater reduction from one floor to the next according to the modern, International Building Code (IBC) definition).
What is difference between soft storey and weak storey?
weak storey is defined as one in which the storey’s lateral strength is less than 80 percent of that in the storey above. A soft storey is one in which late al stiffness is less than 70% of that in the storey immediately above, or less than 80% of the combined stiffness of the three stories above.
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.
Is my building a soft story building?
A soft-story building is a structure which has a weaker first floor and is unable to carry the weight of the stories above during an earthquake. The first floor generally would have large openings in the perimeter walls such as garages, tuck under parking or even large windows.
Is my building a soft story?
A typical soft story building is an apartment building of three or more stories located over a ground-level that has large openings, like tuck-in parking garages, or any other large openings. The first floor is considered weak because it is missing adequate shear walls.
What is soft storey in civil engineering?
Soft storey is the one of which the rigidity is lower than any other storey due to the fact that it has not got the walls with the same properties the other ones have. Soft storey is an irregularity which affects the behavior of a construction during a quake and also increases the construction costs.
What is storey stiffness?
Equivalent storey stiffness of a storey (Ki,eq) is estimated as the lateral force that results in unit lateral translational deformation in that storey (Fig. 4). Thus, this method requires n-additional analyses to estimate storey stiffness of an n-storey building.
How do you stop a soft story?
In case it is necessary, irregularities can be eliminated by increasing the lateral rigidity of this storey by putting up additional walls between single structural elements on the soft storey; placing diagonals between the columns and shear walls; increasing the rigidity of the soft storey by increasing beam-column …
What is a floating column?
Floating column is a type of column which is is constructed over beams or slabs of any intermediate floors of a structure. These columns are not attached to any footings or pedestal. Floating columns are also known as hanging column. ( Refer to the below image)
What are crawl space cripple walls?
Wooden floors and stud walls are sometimes built on top of an exterior foundation to support a house and create a crawl space. These are called cripple walls and they carry the weight of the house. During an earthquake, these walls can collapse if they are not braced to resist horizontal movement.
How much does a 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.