A seismic retrofit is a process that is meant to strengthen a building’s resistance to ground motion during an earthquake. The majority of Bay Area housing was constructed before modern earthquake codes were adopted and are therefore susceptible to damage during an earthquake.
Retrofits usually involve one or all of a couple things: bolting the wood structure to the foundation with epoxy bolts, adding metal hardware at significant parts of the building in order to “collect” the lateral forces and transfer them down to the foundation, and adding plywood panels to the existing wood framing in order to strengthen the lateral resistance of the building.
The access and ease of retrofitting is different for each home, but what is standard across the board is that the potential damage to a structure after an earthquake will almost certainly be more costly than a retrofit.
Structural engineers design buildings to withstand the natural forces that come from gravity, wind, and earthquakes. They work hand-in-hand with architects/owners to design the structural system, or the bones, of a building and work with contractors to ensure that projects are built according to their design. As engineers, it is our job to minimize waste and optimize the design and use of materials in the structure.