The Earthquake Engineering Online Archive

Rate of loading effects on uncracked and repaired reinforced concrete members

Atalay, Mehmet Bilgin; Mahin, Stephen A.; Bertero, Vitelmo V.; Rea, Dixon

UCB/EERC-72/09, Earthquake Engineering Research Center, University of California, Berkeley, 1972-12, 148 pages (550.3/M2/1972)

The effect of high loading rates on the behavior of reinforced concrete structures and the effectiveness of the epoxy-injection technique of repairing cracks in such structures have been studied through tests on six simply supported, doubly reinforced concrete beams. Zones of time-varying moment were developed in the specimens by imposing the same displacement histories at the third points of the beams with electronically controlled hydraulic actuators. Damage in two of the specimens was limited so that they could be repaired by the injection of epoxy resins into cracks and later retested. An additional steel wide flange beam was tested to evaluate the performance of the experimental facilities. Steel and concrete strains, curvatures, and deflections were continuously monitored and are presented in the appropriate hysteretic forms. The results are interpreted with specific regard to the effects of rate of loading and crack repair on the stiffness, strength, ductility and energy absorption and dissipation capacities of the specimens. High rates of loading in regions of essentially pure flexure were found mainly to increase the moment capacity on the first excursion beyond yield. The stiffness of the repaired beams was adequately restored for service loads although the mode of failure of the repaired beams differed from that of the nonrepaired beams as a consequence of their differing load histories.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-72-09.pdf (12 MB)