The Earthquake Engineering Online Archive

Analytical model for concrete anchorages of reinforcing bars under generalized excitations

Ciampi, Vincenzo; Eligehausen, Rolf; Bertero, Vitelmo V.; Popov, Egor P.

UCB/EERC-82/23, Earthquake Engineering Research Center, University of California, Berkeley, 1982-11, 121 pages (555.3/C515/1982)

The model is based on a general local bond stress-slip relationship, derived from the results of a previous extensive study, and on either a bilinear or a simple but sufficiently accurate nonlinear stress-strain relationship for a reinforcing steel bar. An efficient numerical scheme for the integration of the governing differential equation of bond along the embedment length of the bar is presented. The analytical model is then used to predict the bond behavior of a reinforcing bar embedded in exterior and interior joints of reinforced concrete frames subjected to severe load and/or deformation reversals which simulate the effects of earthquake loading. In these joints, besides confined concrete, the concrete that covers the core is unconfined; therefore, a modified analytical model for these cover regions had to be developed. The analytical model is also used to conduct a numerical investigation of the influence on anchored bar behavior of (1) type of analytical model of the stress-strain relationship of the reinforcing bar (bilinear vs. nonlinear), (2) severity of hysteretic requirements determined by the number of imposed cycles and the peak values of the steel strains, (3) main mechanical characteristics of steel (namely, yield stress and rate of strain hardening), and (4) anchorage length.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-82-23.pdf (3 MB)