The Concrete Coalition: A Panel Discussion on Understanding the Policy, Inventory, and Technical Problems Associated with Pre-1980 Concrete Buildings

Earthquake Loss Estimates and Policy Implications for Nonductile Concrete Buildings in Los Angeles

“…The inventory excludes tilt-ups, which largely have been mitigated in compliance with the Los Angeles retrofit ordinance known as Division 91 (City of Los Angeles 1994). For comparison purposes, the Concrete Coalition estimated the number of older concrete buildings in San Francisco to be 3,000 (Comartin et al 2011). Using default replacement costs per square foot specified in Tables 3.6 and 3.7 of the HAZUS™ Technical Manual (FEMA 2003) and using modifiers to reflect inflation and regional construction costs, the replacement value of the building structures alone was estimated to be $17 billion (with contents, replacement estimates were $34 billion).…”

“…The Grand Challenge research project undertaken from 2007 to 2013 included a case study inventory in the City of Los Angeles for loss modeling (Anagnos et al 2008, 2010, 2012; Comerio and Anagnos 2012), extensive experimental laboratory testing of components (Hassan and Moehle 2012, Henkhaus et al 2013, Prasad and Hutchinson 2014), and analytical simulations of ground motions, progressive collapse analyses, and building fragility studies (Star et al 2011, Park and Mosalam 2012, Galanis and Moehle 2015). During this same period, other investigators inventoried these buildings (Comartin et al 2011), studied their performance (Lynch et al 2011, Liel et al 2011, Wu et al 2009), estimated earthquake losses (Baradaran Shoraka et al 2013, Jones et al 2008, Taciroglu and Khalili-Tehrani 2008), and evaluated mitigation strategies (Koutromanos et al 2013; Liel and Deierlein 2012, 2013). In addition, a collaborative project of the National Institute of Standards and Technology (NIST), the Federal Emergency Management Agency (FEMA), the Applied Technology Council (ATC), and the Consortium of Universities for Research in Earthquake Engineering (CUREE) aimed to develop nationally accepted collapse assessment and mitigation guidelines for nonductile concrete buildings (NIST 2010, 2013; ATC 2012; Elwood et al 2012).…”

“…In California, NDC buildings were principally constructed between approximately 1890 (when elevators first enabled the construction of relatively tall buildings) and the mid-1970s (when NDC frame collapses and other significant damage in the 1971 San Fernando earthquake motivated improvements in building codes). The Concrete Coalition estimates that in California alone, 20,000 to 23,000 of these buildings exist, including residential, commercial, schools, and critical service facilities (Comartin et. al.…”

Developing Regional Building Inventories: Lessons from the Field

“…Table 2 shows, for a few selected cities, the data sources that were used by members of the Concrete Coalition to attempt to assess the size and scope of the potential risk due to older concrete buildings for the whole state of California. The complete table is available in the Concrete Coalition final report (Comartin et al 2011). Note that Burlingame and Calabasas did not use Sanborn Maps, possibly because they were not readily available.…”

“…The Concrete Coalition's sidewalk survey of pre-1980 concrete buildings in San Francisco was actually the fourth phase of a broader inventory effort (Comartin et al 2011). In Phase 1, volunteers met at the San Francisco Public Library and counted every concrete building on each of the 1,200 Sanborn maps available for the city.…”