What Risks Do Non-Ductile Buildings Pose In an Earthquake?
There have been an alarming amount of earthquakes in the US over the past few years, specifically in Alaska, California, Hawaii, Oregon and Utah, including a few others. The buildings that have been affected the most in these states are non-ductile buildings (concrete structures) that have not been retrofitted.
The designs and construction of new buildings in CA, for example, are now designed for Life Safety design to help in an earthquake. Older buildings are going to lack those important details which means a much less safe building than you might realize.
California is littered with hundreds of buildings that are non-ductile buildings. These are buildings that have not been retrofitted and are incredibly dangerous.
What Is a Non-Ductile Building?
Non-ductile buildings are also known as “non-ductile concrete” or sometimes, “non-ductile reinforced concrete”buildings. These buildings are brittle and more inclined to break and crack with seismic strain, as implied by the name non-ductile, which means non-flexible. Although non-ductile building construction became less popular in the west coast in the 1960’s, due to earthquake safety concerns, there are still many of these older buildings in California, Oregon, and Seattle which pose a major risk during an earthquake.
The Single Biggest Earthquake Risk
Seismic engineers have a saying; Earthquakes don’t kill people, buildings do! This is why FEMA calls these non-ductile buildings the single biggest contributor to earthquake damage, risk, and injury in the United States.
Not only do the non-ductile buildings pose risk during the earthquake itself, but also during aftershocks which are often more extreme than the earthquake itself, and often cause more damage to already-weakened structures.
Non-ductile buildings are extremely vulnerable in earthquakes because they are brittle and do not have a solid reinforcement. Reinforcement might include buildings that have more rebar, diagonal steel reinforcements, bracing systems, or concrete shear walls.
Considering Building Strength
The type of retrofit needed for your building is going to depend on the type of performance you will want for your commercial space. A hospital, for example, will still need to be functional after an earthquake while a parking garage would not.
If you need a retrofit or if you think you might have one of the many non-ductile buildings around California, contact Saunders Seismic for more information and to schedule an appointment.