Seismic performance of concrete columns reinforced with high strength steel

Test results are presented from an experimental program carried at the University of Texas at Austin aimed at evaluating the seismic performance of concrete columns reinforced with high-strength steel. Comparisons are made between the performance of columns reinforced with conventional Grade 60 steel, and the higher Grade 80. The high-strength steel used in this study is the result of a recent push in the U.S. to produce higher grade reinforcing bars with relatively high ductility. All steel used satisfied the specifications of ASTM A706. Column specimens were tested under constant axial load and reverse cyclic lateral loading until collapse. Columns performed in a similar manner, indicating that current limits on the yield strength of reinforcing bars in seismic applications could be raised to include Grade 80 A706 bars. Conclusions are drawn with respect to the effects of higher strength reinforcement on, member cracking, drift capacity, plasticity spread, plastic hinge performance, and strain demands on reinforcing bars.