Distributed knee-braced (DKB) system as a complete or supplemental retrofit of soft-story wood-frame buildings

M. Gershfeld, C. Chadwell, J. Van De Lindt, W. Pang, E. Ziaei, M. Amini, S. Gordon, E. Jennings

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The NEES-Soft NSF-sponsored project, as one of its objectives, evaluated the performance of various retrofit schemes for "soft-story" light wood-frame buildings subjected to seismic loading. The distributed knee-braced (DKB) system was one of the retrofits evaluated. This system consists of an assembly of light wood-frame knee-braced frames placed so as to reinforce an existing deficient line of resistance. The individual knee-braced frame is constructed by reinforcing existing wall studs with additional stud(s) and connecting them to the existing floor joists with new diagonal 2x wood members. The reinforcement of the members and connections along the knee-braced frame load path are designed to exceed the capacity of the knee-brace to stud and knee-brace to joist connection, thus creating a load fuse. The performance of DKB system was validated using reversed-cyclic testing, numerical modeling, hybrid testing, and shake table testing. The four-frame, 10-ft DKB system was able to develop a maximum lateral load capacity of approximately 2,400 lbs (1088 kg) at 4.5% drift and 1,000 lb (454 kg) at 7.5% drift. The findings suggest that the DKB system can be an effective alternative to other more traditional "soft-story" retrofits by providing strength at very large drift capacities.

Original languageEnglish (US)
Title of host publicationStructures Congress 2014 - Proceedings of the 2014 Structures Congress
EditorsGlenn R. Bell, Matt A. Card
PublisherAmerican Society of Civil Engineers (ASCE)
Pages2863-2874
Number of pages12
ISBN (Electronic)9780784413357
DOIs
StatePublished - 2014
Externally publishedYes
EventStructures Congress 2014 - Boston, United States
Duration: Apr 3 2014Apr 5 2014

Publication series

NameStructures Congress 2014 - Proceedings of the 2014 Structures Congress

Other

OtherStructures Congress 2014
Country/TerritoryUnited States
CityBoston
Period4/3/144/5/14

ASJC Scopus subject areas

  • Building and Construction
  • Civil and Structural Engineering

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