Overview of the NEES-soft experimental program for seismic risk reduction of soft-story woodframe buildings

The existence of thousands of soft-story woodframe buildings in California has been recognized as a disaster preparedness problem resulting in mitigation efforts throughout the state. The considerable presence of these large multi-family buildings in San Francisco prompted the city to mandate their retrofitting over the next seven years. The NEES-Soft project, whose full title is “Seismic Risk Reduction for SoftStory Woodframe Buildings,” is a five-university multi-industry three-year project which has many facets including improved nonlinear numerical modeling, outreach, retrofit methodology development, and full-scale system-level experimental validation of soft-story retrofit techniques. In 2013, two full-scale buildings were tested within NEES-Soft. A hybrid test of a three-story building consisting of a onestory numerical substructure and a two-story physical structure above at the University at Buffalo, and a shake table test of a four-story building at the University of California – San Diego. A series of retrofits, based on methodologies ranging from FEMA P-807 to performance-based seismic retrofits developed as part of the project, were tested at both sites. Collapse testing for both building specimens was also conducted at the end of each test program. This paper presents a summary of selected test results for these full-scale building tests within the NEES-Soft project.