Episode 2 - Is Your Stuff Earthquake Ready?
In the second episode of The Deconstructed Podcast, our amazing hosts, Elide and Andrew, talk to a wood construction expert, Kelly Cobeen, about something else that can go wrong in the typical home during an earthquake. Let’s talk about “nonstructural components”.
First, what are typical nonstructural components in wood homes? It is everything else except the main structure, such as furniture, content (all of your belongings), plumbing and mechanical equipment, chimneys, etc. So what can go wrong with these components during an earthquake? Here are the three most common issues:
(1) Furniture and content falls over (minute 2:26).
Stuff inside your house can fall over during earthquakes. This can not only hurt you directly but also constitute a tripping hazard while you are trying to leave the house. The most hazardous elements are tall and heavy pieces of furniture which tend to topple over, but also shelves. In fact, not only what is on the shelves could fall, but the shelf itself could fall and hit whatever is underneath it. See Figure 1 for an example of residential damage observed after the 1994 earthquake.
Other types of belongings, like smaller items with personal or monetary value, can also get damaged. For example, Kelly Cobeen shared with us that the majority of houses she assessed after the 1994 Northridge earthquake had piles of china and jars broken in their kitchens. Figure 2 shows damage to a kitchen in a townhouse after the 1994 Northridge earthquake. In the case of this picture, the occupant cut her foot on broken glass while running outside of her house in the dark since the power was out.
What can you do to reduce this type of damage (minute 3:58)? You should first anchor the tall and heavy pieces of furniture to the wall and secure what is of value to you. A cheap, proven solution is to install child locks on all cabinets and drawers.
(2) Water heater topples, and water and gas lines break (minute 4:56).
Toppled water heaters can flood the baseline and could start a fire if the gas line breaks. Figure 3 shows an example of unanchored water heaters that fell over. Bracing the heater and adding flexible connections to the gas and water lines could easily and cheaply solve this issue.
(3) Brick chimneys break and fall (minute 6:23).
Brick chimneys are architecturally relevant in many old wood houses, however, they tend to behave very poorly during an earthquake because they are tall, slender, and heavy. It is estimated that 90% of the brick chimneys fell in San Francisco during the 1906 earthquake. While this is a common hazard, it is a complicated problem that does not have an easy fix. If your wood home has a brick chimney and you are concerned about what might happen during an earthquake, you should consult a licensed Professional Engineer. Examples of chimney failures are presented in Figures 4 and 5.
A summary of the recommendations for reducing earthquake hazards in your home is presented in FEMA 258, and reproduced in Figure 6.
LIST OF RESOURCES:
Chapter 6.5. Furniture, Fixtures, Equipment and Content
Chapter 6.3.7: Chimneys
Chapter 22.214.171.124: Water Heaters