The Earthquake Engineering Online Archive

Hysteretic behavior of steel columns

Popov, Egor P.; Bertero, Vitelmo V.; Chandramouli, S.

UCB/EERC-75/11, Earthquake Engineering Research Center, University of California, Berkeley, 1975-09-01, 229 pages (530/P65/1975)

This is the third and concluding report on the project "Inelastic Behavior of Beam-Column Subassemblages." The previous reports were titled Inelastic Behavior of Steel Beam-Column Subassemblages (Oct. 1971) and Further Studies on Seismic Behavior of Steel Beam-Column Subassemblages (Dec. 1973). The results of experiments with eight specimens are given in the above two reports. These specimens were designed with strong columns, so as to have inelastic (hysteretic) behavior in the beams and the panel zones. In this report, emphasis is placed on the strong inelastic (hysteretic) action in the columns of steel beam-column subassemblages. A total of six specimens were tested. In four of these, the columns were bent around their strong axes; in two, around their weak axes. The main objective of these tests was to determine the behavior of column plastic hinges subjected to random pseudostatic cyclic loading. Some tentative conclusions are drawn from the results of the analyses presented: (1) The application of moderate intensity inelastic cyclic moments to axially loaded columns is possible, provided the P/P subscript y ratio remains less than 0.5. At higher P/P subscript y ratios, there was a sharp drop in strength which was precipitated by flange buckling. (2) Panel zones can be effectively reinforced with doubler plates. Some inelastic action in such plates can be permitted since strain-hardening tends to arrest excessive deformations. (3) The moment capacity of columns in cyclic loading tends to be much greater than that calculated on the basis of the simple plastic theory. This is due to the strain-hardening of steel.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-75-11.pdf (61 MB)