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Title: Seismic Risk Reduction for Soft-Story Wood-Frame Buildings: Test Results and Retrofit Recommendations from the Nees-Soft Project

Source: In: WCTE 2014, World Conference on Timber Engineering, Quebec City Canada, August 10-14; 2014; 9 p.

Author(s)Lindt, John W. van de; Bahmani, Pouria; Gershfeld, Mikhail; Mochizuki, Gary; Shao, Xiaoyun; Pryor, Steven E.; Pang, Weichiang; Symans, Michael D.; Tian, Jingjing; Ziaei, Ershad; Jennings, Elaina N.; Rammer, Douglas

Publication Year: 2014  View PDF »

Category: Conference Proceedings
Associated Research Project(s):   FPL-4714-3B

Abstract: There are thousands of soft-story wood-frame buildings in California which have been recognized as a disaster preparedness problem with concerted mitigation efforts underway in many cities throughout the state. The vast majority of those efforts are based on numerical modelling, often with half-century old data in which assumptions have to be made based on engineering judgment and project committee consensus. The NEES-Soft project, whose full title is “Seismic Risk Reduction for Soft-Story Wood-frame Buildings,” is a five-university multi-industry three-year project with many facets including improved nonlinear numerical modelling, outreach, design method development, and full-scale system-level experimental validation of soft-story retrofit techniques. In 2013, two full-scale buildings were tested within NEES-Soft. The first was a three-story building tested at the University at Buffalo NEES facility using slow pseudo-dynamic testing. The bottom story, representing a soft story with garage openings, was the numerical substructure reproduced by computer, while the damage to the two upper stories, representing the physical substructure, was observed in the lab and provided feedback to the actuators. This test had the main objective of determining the effect of the retrofits on damage to the upper stories and collapse risk of the complete structure. The second major test was on a full-scale four-story 400 square meter soft-story building. It was tested by the NEES-Soft project team at the UCSD NEES outdoor shake table facility using a variety of retrofits. These retrofits ranged from FEMA P-807 retrofits to performance-based seismic retrofits developed as part of the project. Both tests demonstrated the effectiveness of the FEMA P-807 retrofit guidelines and the NEES-UCSD test validated the PBSR methodology developed within the NEES-Soft project.

Keywords: Wood-frame; soft-story; earthquake; collapse; seismic retrofit; FEMA P807; risk reduction

Publication Review Process: Formally Refereed

File size: 812 kb(s)

Date posted: 08/29/2014

This publication is also viewable on Treesearch:  view
RITS Product ID: 68563
Current FPL Scientist associated with this product
Rammer, Douglas R.
Research General Engineer

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