San Francisco Nonductile Concrete Buildings Part I: Building Inventory

October 17, 2019
Publication: 2019 SEAOC Convention
Author(s): Keith Palmer Pearl Ranchal Kari Klaboe Duke Crestfield Stephen Kadysiewski Laurence Kornfield Robert Kraus

Over the years, there has been much focus within California on seismically vulnerable building types, with the ultimate goal being to reduce life safety risks, improve community resiliency, or achieve a balance of both objectives. In San Francisco, preservation of housing is a prime objective. Numerous studies have identified unreinforced masonry, SWOF (soft, weak, or open front), and nonductile concrete (NDC) buildings as performing particularly poorly when subjected to strong ground shaking. While some mitigation programs to address the first two vulnerable building types have been previously implemented statewide and in San Francisco, NDC buildings are a vulnerable building type within the California building inventory that remain largely unaddressed by policy in jurisdictions around the state. Staff and interns at The EPICENTER, an earthquake policy center operated by the City and County of San Francisco, collaborated with SEAONC’s Existing Buildings Committee over summer 2018 to develop a comprehensive inventory of concrete buildings in San Francisco based on public records and historic documentation. This building inventory is being used by the City of San Francisco to better understand the scope of the NDC problem and in the development of a mandatory building analysis and retrofit ordinance for these buildings. The inventory is also used as input to a companion paper on the Analysis, Assessment, and Comparison of Older Concrete Buildings. This work builds upon preliminary inventory work previously undertaken by the Concrete Coalition and the Earthquake Engineering Research Institute.