Seismic retrofit of R/C columns using steel jackets

Riyad S. Aboutaha, Michael D. Engelhardt, James O. Jirsa, Michael E. Kreger

Research output: Chapter in Book/Entry/PoemConference contribution

5 Scopus citations


Inadequate shear strength and inadequate lap splices in the longitudinal reinforcement are two major deficiencies in non-ductile reinforced concrete columns. Such deficiencies limit the lateral strength and ductility of older reinforced concrete moment resisting frames. Provisions of older codes led to columns with shear strength less than required to develop the member's flexural capacity. Consequently, non-ductile shear response may dominate the behavior of older short columns. In addition, lap splices in older concrete columns were primarily designed as compression splices, but may actually experience large tensile forces during earthquakes. As a result, lap splices in older concrete columns are often inadequate to develop the yielding strength of the spliced bars in tension. This paper presents results of an experimental investigation on the use of rectangular steel jackets for seismic retrofit of rectangular reinforced concrete columns with inadequate shear strength or inadequate lap splices. Three large scale columns with inadequate lap splices and four large scale columns with inadequate shear strength were tested under lateral cyclic loading. The basic unretrofitted columns showed early dramatic non-ductile failures. However, the retrofitted columns with steel jackets exhibited excellent response, higher strength and much higher ductility and energy dissipation. Test results suggest that rectangular steel jackets can considerably improve the performance of columns with inadequate shear strength. Also, the steel jackets can significantly enhance the response of wide columns with inadequate lap splices, when stiffened with adhesive anchor bolts.

Original languageEnglish (US)
Title of host publicationSeismic Rehabilitation of Concrete Structures
EditorsGajanan M. Sabnis, Avanti C. Shroff, Lawrence F. Kahn
PublisherAmerican Concrete Institute
Number of pages14
ISBN (Electronic)9780870316586
StatePublished - Jun 1 1996
Externally publishedYes
EventSeismic Rehabilitation of Concrete Structures at 1994 ACI Spring Convention - San Francisco, United States
Duration: Mar 20 1994Mar 25 1994

Publication series

NameAmerican Concrete Institute, ACI Special Publication
ISSN (Print)0193-2527


ConferenceSeismic Rehabilitation of Concrete Structures at 1994 ACI Spring Convention
Country/TerritoryUnited States
CitySan Francisco


  • Anchor bolts
  • Columns (supports)
  • Ductility
  • Earthquake-resistant structures
  • Hysteresis
  • Lap connections
  • Reinforced concrete
  • Shear strength

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science


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