If you live in an area that is prone to earthquakes, such as Seattle, you should consider having a seismic retrofit done. Seismic retrofitting is a process of strengthening a building or structure to better withstand the effects of an earthquake. It is important to note that seismic retrofitting should be done on any structure that has been built before building codes began to require earthquake resistance which is around 1980.
Reasons to retrofit:
Life and Safety of Occupants
Minimize Property Damage
Reduce Liability for Building Owners
Insurance Deductibles are high
Be able to live in your house after an earthquake
Reduce Financial Risk
The first and foremost reason to retrofit is to provide safety to those who occupy the building.
As an owner, you may be liable. An owner in California was found liable in court for the deaths of 2 occupants in an earthquake even though there wasn't a requirement to retrofit. An ordinance requiring a retrofit was in effect but the owners had years to get it done and they deferred. Because they knew their structure was not fit to withstand an earthquake, they lost their case.
Types of buildings that need retrofits:
Residential homes built before 1980
Softstory (tuck under parking) apartments
URM (Unreinforced Masonry Brick)
One of the primary failure points that should be addressed in a URM building is the parapet. The parapet is likely to fall onto the sidewalk in an earthquake. In upcoming city of Seattle requirements - this will absolutely be part of the requirement. The parapet needs to be braced to the roof.
The first thing to understand when considering seismic retrofitting is the types of structures that are most at risk for damage in an earthquake. Generally, unreinforced masonry, wood-frame structures, and soft-story buildings are most at risk of damage from an earthquake. If your apartment building has tuck under parking - this is a soft story condition. Unreinforced masonry is a type of construction where the walls are made of brick or adobe and are not connected together with steel or reinforced concrete. Wood-frame structures are buildings constructed with wood framing and can include plywood sheathing and wood siding. Soft-story buildings are buildings with an open space or “soft” story, such as a garage or carport, on the first floor. These buildings are particularly vulnerable to earthquake damage because they have less rigid support on the bottom floor.
In addition to the type of structure, the date the property was built can also be a factor in determining whether a seismic retrofit is necessary. Buildings built before the 1970s are much more likely to suffer damage due to an earthquake and should be considered for seismic retrofitting.
Overall, seismic retrofitting is an important step to take in order to protect your property and reduce the risk of damage due to an earthquake. It is important to understand the types of structures that are most at risk and the date the property was built in order to determine if a seismic retrofit is necessary.
Need help determining whether your property is at risk? Book a free seismic assessment with us today.