Eleventh U.S. National Conference on Earthquake Engineering Integrating Science, Engineering & Policy June 25-29, 2018 Los Angeles, California VULNERABILITY BASED SEISMIC ASSESSMENT AND RETROFIT OF ONE- AND TWO-FAMILY DWELLINGS (ATC-110 PROJECT) C. Blaney 1 , V. Bourcier 2 , K. Cobeen 3 , A. Filiatrault 4 , D. Welch 5 , M. Stoner 6 , W. Pang 7 , and T. Vincent 8 ABSTRACT The California Earthquake Authority (CEA) and the Federal Emergency Management Agency (FEMA), through the Applied Technology Council’s ATC-110 Project series, have sponsored development of a prestandard for seismic assessment and retrofit of cripple wall, house-over- garage, and hillside vulnerabilities in residential wood dwellings. Although simplified for the purposes of implementation, methodologies are being developed using best available numerical tools and performance objectives consistent with the philosophies of current seismic codes and standards. After almost three years of work, prestandard provisions and prescriptive plan sets for assessment and retrofit are nearing completion. This paper discusses the project methodology, illustrates retrofit approaches and interim numerical study results, and shares insights gained. 1 Structural Engineer, Buehler & Buehler, San Carlos, CA 94070 (cblaney@bbse.com) 2 Structural Engineer, Hohbach-Lewin, Inc., 296 East 5th Ave. Suite 302, Eugene, Oregon 97401 (vbourcier@hohbach-lewin.com) 3 Structural Engineer, Wiss Janney Elstner Assoc., Emeryville, California 94608 (kcobeen@wje.com) 4 Professor, Department of Civil, Structural and Environmental Engineering, University at Buffalo, State University of New York, Buffalo, NY 14260 (af36@buffalo.edu) & University School for Advanced Studies IUSS Pavia, Italy (andre.filiatrault@iusspavia.it) 5 Post-doctoral researcher, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305 (dpwelch523@gmail.com) 6 Graduate Student, Glenn Department of Civil Engineering, Clemson University, Clemson, SC 29634 (mwstone@g.clemson.edu) 7 Associate Professor, Glenn Department of Civil Engineering, Clemson University, Clemson, SC 29634 (wpang@clemson.edu) 8 Staff Engineer, Hohbach-Lewin, Inc., 296 East 5 th Ave. Suite 302, Eugene, Or 97401 (tvincent@hohbach- lewin.com)