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Local Bond Stress-Slip Relationships of Deformed Bars Under Generalized Excitations: Experimental Results and Analytical Model.
Eligehausen, R.; Popov, E. P.; Bertero, V. V.
National Science Foundation, Washington, DC., October 1983, 190 p.
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This report covers integrated experimental and analytical investigations that permit predicting analytically the local bond stress-slip relationship of deformed reinforcing bars subjected to generalized excitations, such as may occur during the response of reinforced concrete (R/C) structures to severe earthquake ground motions. Some 125 pull-out specimens were tested. Each one of these specimens simulated the confined region of a beam-column joint. Only a short length (five times the bar diameter) of a Grade 60 deformed reinforcing bar was embedded in confined concrete. The tests were run under displacement control by subjecting one bar end to the required force needed to induce the desired slip which was measured at the unloaded bar end. The influence of (1) loading history, (2) confining reinforcement, (3) bar diameter and deformation pattern, (4) concrete compressive strength, (5) clear bar spacing, (6) transverse pressure, and (7) loading rate on the bond stress-slip relationship was studied. Based on the experimental results, a relatively simple analytical model for the local bond stress-slip relationship of deformed bars embedded in confined concrete is developed. The main assumption is that bond deterioration during generalized excitations depends on the damage experienced by the concrete, which, in turn, is a function of the total dissipated energy.
Dynamic structural analysis; Stress (Mechanics); Mechanical hystereses; Earthquake engineering; Beams (Supports); Loads (Forces); Dissimilar materials bonding; Reinforcing materials; Reinforced concrete; Deformation (Elastic); Excitation; Columns (Supports); Slip (Mechanical); Mathematical modeling; Deformation; Bars; Deterioration