Seismic Retrofitting: What You Need to Know
Updated: Dec 20, 2022
When it comes to preparing for a major earthquake, seismic retrofitting is an important part of the equation. Seismic retrofitting is the process of strengthening existing structures to make them more resistant to earthquake damage. And while it’s not a guarantee of absolute safety, it can greatly reduce the risk of major structural damage during an earthquake.
So, what exactly is a seismic retrofit? It’s the process of reinforcing a structure’s frame and sometimes foundation to make them stronger and more able to withstand the force of a major earthquake. This is done by adding reinforcing materials to the existing structure, such as steel beams and concrete, and using special fasteners to secure the structure together.
To make a property earthquake-proof, the first step is to identify and address any existing structural weaknesses in the building. This can include anything from unstable walls to weak foundations and even cracks in the walls. Once these weaknesses have been identified, they can be addressed by either repairing them or by adding seismic retrofitting measures. Often times for a single family home, its a rather simple procedure of adding anchor bolts and wood shear walls.
Most often for a single family home we will prescribe:
Anchor bolts (Titen HD or Strongbolt 2)
Anchor plates (URFP or FRFP)
Additional studs and framing called blocking (Douglas Fir #2)
Holddowns (HDU2 or HDU4)
Wood shear walls (CDX grade plywood nailed to all studs and framing)
Framing clips (L70 or A35)
When it comes to stabilizing equipment and systems within a building, there are several methods used for seismic retrofitting. One of the most common methods is the use of base isolation systems, which utilize a series of pads or bearings to help absorb the shock of an earthquake.
Certain types of structures are at a higher risk of earthquake damage, such as those with soft-story construction or those made from unreinforced masonry. Just because your house is brick does not means its unreinforced masonry. This is something we will check for during our assessment. URM and soft-story buildings are especially vulnerable to seismic activity, and should be retrofitted as soon as possible to help prevent major damage.
Geographic locations that are prone to earthquakes should also consider retrofitting their buildings. This includes areas such as the Pacific Northwest, California, Oregon, Alaska, and Hawaii, which are all susceptible to major earthquakes. By retrofitting these buildings, property owners can help protect their investments and help protect the lives of their tenants.
Seismic retrofitting is an important step in preparing for an earthquake, and it’s important that property owners take the time to assess the existing structures on their property and determine if they need to be reinforced. By making these preparations ahead of time, they can help reduce the risk of major damage and injury during an earthquake.
Wondering whether a seismic retrofit is right for your property? Book a free seismic assessment with us today.