Mandatory seismic retrofits contemplated for vulnerable structures

The City of Seattle’s Department of Planning and Development (DPD) briefed City Council today on possible new requirements for the city’s un-reinforced masonry buildings (URM’s).  The briefing included information from a recently completed study by the Reid-Middleton engineering firm, commissioned by the city, which estimates there are up to 1000 URM’s in the city, most of which have not been seismically retrofitted. The study also summarizes the experience of several California cities which have instituted a similar requirement over the past two decades.  Those cities offered 10 years or more for building owners to meet the new requirements.

“This is a public safety issue,” said Mayor Nickels.  “No one‘s rushing into this decision, and we will deliberate over the coming months before reaching any conclusions.  But Seattle is in earthquake country and URM’s are our most vulnerable structures.  We need to address the issue of safety in these structures in a major quake.”

In the Nisqually earthquake of 2001, a relatively mild seismic event, two-thirds of the buildings in Seattle that were closed due to earthquake damage were URM’s.  Currently, Seattle requires seismic retrofits when a building is undergoing substantial alterations or substantially increasing the number of occupants in the building. 

In the coming months, DPD will convene a technical committee to begin assessing what seismic standard would be required for URM’s if the new mandatory fix is adopted.  A policy committee will develop positions concerning how long owners would have to meet the new requirement, which structures it will apply to, and what the penalties might be for not complying within the set time period. The city will also be researching sources of funding support for owners of URMs, particularly those providing affordable housing and human services, as well as landmarked buildings.

If adopted, Seattle would be the first city outside California to adopt such a requirement.  Scientific information in recent years has raised the projected risk of significant damage from earthquakes in Seattle.