It may have escaped your notice during this week's Great Utah ShakeOut earthquake drill that you live in a house made of unreinforced brick. There are many such homes along the Wasatch Front, more than 30,000 of them in Salt Lake City alone. That simple fact could place your life at risk during a major earth tremor as your home collapses around you. Fortunately, there are things you can do to shore up your home.
The Utah Seismic Safety Commission has assembled an information kit online at ussc.utah.gov/publications.html. It's titled, appropriately enough, "The Utah guide for the seismic improvement of unreinforced masonry dwellings." It includes a primer on the hows and whys of risk posed by these buildings during quakes, and what can be done to improve their safety. Most interesting is a series of six model houses in styles that you will readily recognize from the Salt Lake City area. If you live in a brick house, it probably will resemble one of these examples.
The guide is full of drawings, diagrams and photographs. The information explains the weaknesses typical of each style of home and the retrofitting building techniques that can improve their safety.
As the guide explains, "Unreinforced masonry dwellings were typically constructed prior to 1970, when seismic requirements were added to the Uniform Building Code. They were normally constructed with solid masonry-bearing walls without adequate reinforcement. As a result, URM structures lack the ability to move beyond the elastic limit required to absorb the seismic energy in an earthquake. Often the structures are quite brittle and can quickly fail when seismic activity is present. Thus, such URM structures should not be expected to perform adequately through a large seismic event."
In other words, brick houses may be just the ticket to withstand the huffing and puffing of the Big Bad Wolf, but severe earthquakes? Not so much.
Houses made of unreinforced masonry cannot be made earthquake-proof. But they can be made safer. Homeowners can get basic knowledge about the problems and solutions from the website. Depending upon their skill as builders, they might be able to make some of the improvements themselves. More likely, they may need to consult professionals.
Governments and school districts have invested hundreds of millions of dollars retrofitting schools and public buildings to better withstand "the big one." But as a private homeowner, it's up to you to decide whether to undertake such work.