Disaster Zone: Unreinforced Masonry Buildings
January 31, 2020
Category: Guest Author , Emergency Management
Earthquakes are one of the more significant disaster types that we have here in Washington State. Much has been written about the Cascadia Subduction Fault and the devastation it will bring to Western Washington. This is especially true along the coast, due to the creation of tsunami waves crashing ashore; however, there are other earthquake risks that exist and not just in Western Washington. Other areas of the state, for example the Tri-Cities and Spokane, also have earthquake risks.
Earthquakes can cause damage to public utilities, transportation routes, and buildings. Fortunately, traditional wood-framed homes are flexible enough to absorb the shock of earthquake forces. However, there is one type of building, commonly known as an unreinforced masonry (URM) building, that do not share that trait. You find these older buildings (many are composed of brick) throughout towns and cities in Washington State. They were built before modern seismic building codes were developed and may therefore be vulnerable to failure during significant seismic events. Many of the state’s older school buildings that are still in use are URM.
This type of building is the one most likely to collapse in an earthquake, with the floors separating from the walls and “pancaking” down, likely killing and injuring all inside when it is occupied.
In recent years there have been several studies commissioned and completed that call out the specific risks of not addressing URM structures. See the two reports below and a news article on the results of a seismic study of schools.
- Resilient Washington State, 2012
- Resilient Washington Subcabinet Report, 2017
- Study: State’s schools at risk in quake
The City of Seattle has done a detailed analysis of their building inventory to identify specific buildings classified as URM.
If we understand the risks of URM buildings, and in some cases have identified specific buildings in danger of collapsing, why hasn’t anything been done to cause these structures to be made safer?
The issue above has to do with both public safety and funding. Some of the general arguments against updating URM buildings include:
- Some buildings are of historical significance and altering the look of the structure or tearing them down runs counter to the need to preserve our history.
- If owners are forced to either retrofit the building, or in some cases, tear them down, it will cause rents to go higher, causing more stress on the cost of housing for a city or region. If a building is torn down, this action will eliminate a source of lower-cost housing.
- Fixing a school building will only put additional stress on school district budgets when funding is already stretched thin.
The Seattle Times is the source of numerous good articles on the topic of URMs, and this one, Seattle’s old brick buildings could see huge damage in big quake, provides good information on what makes these structures risky. With little public pressure to act on this public safety issue, the easiest course of action has all too often been to take no action.
If you are looking for a place where action has been taken to address URM you should look at what California has done, as the City of Seattle has in its Summary of URM Retrofit Laws for California Jurisdictions.
Likely the frequency and history of earthquakes in California has moved their locally elected officials to act. In Washington State, which is rated the second most at-risk state in the United States for earthquakes, the impetus to take action has not been there.
As noted in the linked documents above, unreinforced masonry buildings pose a clear and present danger for all who live and work in them. What has been lacking is the political will to take the actions necessary to effectively address this threat. What is not needed are more studies. Steve Palmer, the geoscientist who did most of the liquefaction mapping for Washington State, lamented that major action on seismic safety might only come in the aftermath of a deadly earthquake. Is it possible that we can prove him wrong?
One last note: A National Level Exercise called Cascadia Rising 2022 will be held in June 2022. It will do nothing to proactively address the issue of URM in this state.
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