Unreinforced Masonry Buildings
We have completed the validation of our Unreinforced Masonry (URM) building inventory list. Our validation process involved combining all the lists available from previous studies into one list, removing the duplicates, and verifying if the remaining buildings contain URM bearing walls. The verification process used publicly available data in the form of exterior views of the buildings, building plans from our microfilm library, and historical documents from the Seattle Public Library.
We have posted the validated list on the Project Documents page. Our validation has confirmed that there are 1164 URM buildings located throughout Seattle.
We have also posted a report to the policy committee on the Project Documents page. Our report contains extensive analysis of the data about the URM building stock. There are maps showing the locations of the URMs and charts showing the different sizes of the buildings, different occupancies, and the building retrofit status, along with many other attributes.
We notified the building owners by mail, in early April 2016, that their buildings are on the list of confirmed URMs. All building owners have the right to appeal the determination of URM building status by hiring an engineer to perform an in-depth analysis of the building to determine if the building does not contain any URM bearing walls. This in-depth analysis is beyond the scope of what the City could do in our validation efforts.
For more information:
Nancy H. Devine, P.E., S.E.
Senior Structural Plans Engineer
Public safety is the primary reason for requiring retrofits of URMs. However, there are also concerns about maintaining important buildings that are the heart of the historic and cultural character of many neighborhoods. Requiring retrofits for URMs means that more of these “character buildings” may be preserved after an earthquake. It may also result in less building demolition or vacancy. Retrofits can help lessen damage to these buildings, allowing businesses to reopen in a timely manner following a smaller earthquake; a City’s resiliency is key to recovery.
Once the policy is adopted and legislation approved, we will develop a program to require owners to retrofit their URM buildings. We currently only require seismic upgrades when an owner is doing a large remodel to a building. The upgrades typically do not bring the URMs up to current code, but they do help stabilize the buildings enough to make them less vulnerable to collapse during earthquakes.
We anticipate that the program will have tools and incentives to help building owners. We would like to encourage owners to go beyond minimum code for seismic retrofit. Renovation beyond the code requirements increases the potential for buildings to be quickly occupied after an earthquake.