Turk & Eddy Apartments Seismic Retrofit

Coffman provided structural engineering services related to seismic risk analysis and seismic retrofit oriented toward specific performance objectives. These services were provided for the two subject buildings at 165 Turk Street and 249 Eddy Street in the Tenderloin neighborhood of San Francisco. These buildings are 6- and 7-story apartment buildings built in the 1920s, constructed with wood floor framing supported on steel beams and columns, with reinforced concrete exterior walls.

Coffman was hired to develop a schematic structural design of retrofit measures that would enable these buildings to meet specific seismic risk levels and to quantify the resulting scenario expected losses (SELs) and scenario upper losses (SULs). This approach and these results were approved by the lender, and Coffman was subsequently hired to complete the design that we recommended. We worked collaboratively with the owner, Tenderloin Neighborhood Development Corporation, to both develop details that would be easily constructed and to help schedule the construction in a way that would be least impactful to the tenants (many of whom were seniors).

Retrofit measures consisted of new Fiber Reinforced Polymer (FRP) strengthening of certain existing concrete walls, diaphragm strengthening, wall-to-diaphragm anchorage, and diaphragm collectors and ties at re-entrant corners. This project helped to ensure seismic safety for many senior tenants who were able to continue living in familiar surroundings.


  • Hospitality & Housing


  • Structural Engineering