SDCI is celebrating a major milestone on the pathway to improving Seattle’s earthquake safety. On September 26, 2023, the Public Safety and Human Services Committee voted 5-0 to refer Resolution 32111 to a Council vote. This resolution supports the development of a voluntary seismic retrofit ordinance that will establish a minimum seismic safety standard for the retrofit of unreinforced masonry (URM) buildings. URM buildings are classic red brick buildings, generally constructed before 1945, and are prone to collapse in an earthquake. Seattle has 1,100 URM buildings and an 86% chance of experiencing a damaging earthquake in the next 50 years. Adopting a mandatory URM retrofit ordinance continues to be the City’s long-term goal. However, adding a short-term goal to adopt a voluntary URM retrofit ordinance provides assurance to URM building owners that by retrofitting to the established standard, they will be compliant with future mandatory requirements. Resolution 32111 is scheduled for a vote by full Council on October 10.
SDCI published the 2023 Draft URM Retrofit Technical Standard in June that will inform the minimum seismic safety standard of the future voluntary URM retrofit ordinance. It establishes two retrofit methods for URM building owners, the code-based method or the Alternate Method.
- The code-based method uses the Seattle Existing Building Code for compliance with seismic retrofit performance levels of a substantial alteration.
- The Alternate Method, available for use by URM owners as outlined in Director’s Rule 6-2023, results in a building upgrade that provides a minimally acceptable level of safety from collapse. This method includes bracing parapets, strengthening connections between walls and floors, and preventing the walls from falling outwards. This option is limited to buildings that meet specific criteria.
To help communicate the multiple pieces of URM legislation and how they are connected, SDCI created the process graphic below. Each of the five squares represents a piece of legislation, their associated regulation, and the legislative pathway to a future mandatory URM retrofit ordinance. Flowing left to right, the first square represents the 2023 Draft URM Retrofit Technical Standard that establishes two pathways for URM retrofits, either the code-based method or the Alternate Method. The second square represents Director’s Rule 6-2023, demonstrating partial adoption of the 2023 Draft URM Retrofit Technical Standard by allowing the voluntary use of the Alternate Method for retrofit. The third square represents the proposed URM Voluntary Retrofit Resolution 32111 that directs SDCI to create a voluntary URM retrofit ordinance informed by the 2023 Draft URM Retrofit Technical Standard. The fourth square represents the voluntary URM retrofit ordinance which will establish a compliance standard, informed by the 2023 Draft URM Retrofit Technical Standard, for URM owners voluntarily choosing to retrofit. The fifth and final square represents the mandatory URM retrofit ordinance which will require URMs be retrofitted, using the compliance standard adopted by the voluntary URM retrofit ordinance. The mandatory requirement will only be adopted once there are supportive financial resources in place.
SDCI is still developing a timeline for mandatory compliance and other key aspects of a future mandatory retrofit program. As part of this process, we are identifying funding options to help building owners cover the costs of the retrofits.
The 2023 Draft URM Retrofit Technical Standard was developed by a cross-sector team of subject matter experts from SDCI and local structural engineers who are familiar with regional practice related to URM evaluation, design, and retrofit methodology. This team was formed in 2022 to update the previous 2012 Draft Retrofit Standard to reflect the current understanding of regional seismic hazards and building codes. The updated standard includes a clearer scope of retrofit and testing requirements to qualify for using the alternate method for retrofit. Additionally, the update establishes criteria for recognizing previous seismic retrofits which will help URM building owners understand how future mandatory retrofit requirements may impact them.