The ATC-71-1 (FEMA P-807) report, Seismic Evaluation and Retrofit of Multi-Unit Wood-Frame Buildings with Weak First Stories, was funded by the Federal Emergency Management Agency (FEMA) under the ATC-71-1 project. (Published 2012, 226 pages)
ABSTRACT: This document provides guidance on guidelines for the seismic retrofitting of weak-story, wood-frame buildings in seismically active regions, with a focus on multi-family, multi-story buildings with weak first stories, such as those damaged in the 1989 Loma Prieta earthquake, and on apartment buildings with tuck-under parking, such as those damaged in the 1994 Northridge earthquake. These are the first guidelines to focus solely on weak first stories and on incorporating just enough added strength to protect the first floor from collapse but not enough to drive earthquake forces into upper stories, placing them at risk of collapse. They are also the first guidelines to take into account the strength provided by existing nonstructural walls, which makes retrofitting more affordable. The print version of FEMA P-807 includes an attached CD containing a related spreadsheet tool.
Product support for this report and the Weak-Story Tool can be found here. An electronic copy of this report is available in the "More Info" tab.
Note: FEMA documents are available online free of charge, and in hard copy by contacting FEMA (phone: 1-800-480-2520). The above cost is the cost of handling.