The 14 th World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China LOS ANGELES INVENTORY OF NONDUCTILE CONCRETE BUILDINGS FOR ANALYSIS OF SEISMIC COLLAPSE RISK HAZARDS T. Anagnos, 1 M. C. Comerio, 2 C. Goulet, 3 H. Na , 4 J. Steele, 5 and J. P. Stewart 6 1 Professor, Dept. of General Engineering, San José State University, San José, CA USA 2 Professor, Dept. of Architecture, U.C. Berkeley, Berkeley, CA USA 3 Research Associate, 4 Student, 6 Professor, Dept. of Civil & Environmental Engineering, U.C. Los Angeles, Los Angeles, CA USA 5 Research Associate, U.C. Berkeley, Berkeley, CA USA Email: tanagnos@email.sjsu.edu, mcomerio@berkeley.edu, goulet@ucla.edu, steele.jj@gmail.com, jstewart@seas.ucla.edu ABSTRACT : Nonductile concrete buildings arguably represent the greatest seismic life safety hazard in many urban centers world-wide because of their collapse potential. This paper documents the development of an inventory to evaluate the risk from the approximately 1600 potentially nonductile concrete buildings in the City of Los Angeles. Using state-of-the-art spatial databases, publicly available online resources, and building inspections, we record the geographic distribution of these buildings as well as their general characteristics with respect to structural configurations and usage. We describe the diverse array of data sources used to develop the inventory, which provides information on building size, age, type, usage, and ownership type. We particularly emphasize the data collection methodologies developed and utilized for this project and the significant challenges associated with data collection of this type. This information is being utilized in ongoing collapse risk studies related to nonductile concrete construction in Los Angeles and to guide a testing/simulation program that will ultimately lead to more accurate loss estimation tools. KEYWORDS: Nonductile concrete, inventory collection, risk evaluation 1. INTRODUCTION Nonductile concrete buildings were a prevalent construction type in highly seismic zones of the U.S. prior to enforcement of codes for ductile concrete in the mid-1970s. In California, nonductile concrete buildings were principally constructed between approximately 1890 (when elevators first enabled the construction of relatively tall buildings) and the mid 1970s (when improvements in building codes were implemented that reduce collapse risk). This type of construction is common internationally as well, and remains widespread in many developing countries. In California, alone, it is estimated there are 40,000 of these buildings, including residential, commercial, schools and critical service facilities (OES, 2004, p. 97). The poor seismic performance of nonductile concrete buildings was evident in recent earthquakes including Northridge (1994); Kobe, Japan (1995); Chi Chi, Taiwan (1999); Kocaeli, Turkey (1999); Sumatra (2005); Pakistan (2005); and Sichuan, China (2008). In this paper, we describe the process by which an inventory of nonductile concrete buildings is being assembled for the City of Los Angeles. Inventories such as this are a first crucial step toward understanding the scale of the problem associated with this type of construction. The inventory remains a work in progress, so we are not presenting here a summative description. However, innovative use of online publicly available data has been effective in relation to data collection and synthesis. We expect such innovations will be useful for other regions facing similar problems, which is the motivation for presenting this information at the present time.