Soft Story Protection after July, 1999
Until July of 1999 it was legal to build garages with living areas above them with shear walls on each side of the door only 32 inches wide. The 1994 Northridge earthquake proved these narrow shear walls were very unstable and often collapsed. As a result, companies such as Simpson StrongTie invented narrow walls called Simpson Strong Walls that, though much narrower, still perform as well as much wider shear walls. This is proprietary hardware available at building supply stores.
The first to do is cut through the concrete slab so soil can be excavated. This is a very dusty procedure and we take care to cover all personal property with plastic. Simpson Strongwalls still need a structural engineer to determine how much steel and concrete will be required.
Once we cut two slots in the concrete, we break out the concrete to expose the ground and then dig a trench as specified by the structural engineer. Engineering is required in Simpson Strongwall installations.
Next we fill the trench with steel reinforcing. Often these trenches are quite large, depending on the size of the Simpson Strongwall, which can vary considerably.
The steel reinforcing is then attached to the Simpson Strongwall and the Strongwall is then attached to the floor, completing the retrofit process. Simpson Strongwalls are often used on either side of a garage door opening, either in new construction or in retrofits.