SHEAR IN BEAM-COLUMN JOINTS IN SEISMIC DESIGN OF STEEL FRAMES

This paper discusses the importance of joint shear in the response of frame structures to severe earthquakes. Presently used AISC design criteria for joint shear are reviewed in the light of limited experimental evidence. The effects of high shear in joints on the strength, stiffness, and energy-dissipation characteristics of frames are discussed. The most important conclusions can be briefly summarized: Joints usually are very ductile elements capable of undergoing severe inelastic strain reversal without a decrease in strength. The shear force defined by the AISC design equation for combined gravity and lateral loads usually causes some inelastic deformation in joints. This is reduced when the allowable shear stress is modified by the factor alpha, which accounts for the effect of the axial force in the column on the yield stress in shear. Solutions for the ulimate shear strength, associated with controlled inelastic distortions, are given, for joints with unreinforced and reinforced webs, respectively. When joints are designed according to allowable stress criteria, inelastic deformations may be concentrated primarily in the joints and to a lesser degree in plastic hinge regions of beams and columns. Maximum strength and stiffness of frames is attained when all joints are designed for the maximum shear force that can be developed based on the strength capacity of the members framing into the joint. The need for this design criterion has not been fully established, although it is widely used in areas of high seismicity. If this criterion is used, the joints should be permitted to participate in energy dissipation through inelastic deformations. Joint distortions contribute significantly to the elastic story drift in frames. Equations are given which permit an estimate of the effect of these distortions on the lateral deflections.

  • Availability:
  • Corporate Authors:

    American Institute of Steel Construction

    101 Park Avenue
    New York, NY  USA  10017
  • Authors:
    • Krawinkler, H
  • Publication Date: 1978

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 82-91
  • Serial:
    • Engineering Journal
    • Volume: 15
    • Issue Number: 3
    • Publisher: American Institute of Steel Construction
    • ISSN: 0013-8029

Subject/Index Terms

Filing Info

  • Accession Number: 00188441
  • Record Type: Publication
  • Source Agency: Engineering Journal
  • Files: TRIS
  • Created Date: Mar 14 1979 12:00AM