Twelve large-scale tests (7 m beams with 30 mm main reinforcement) were made to investigate the performance of lap splices in reinforced concrete beams subjected to reversed cyclic loading which produced yielding in the main reinforcement. Load history and various configurations of splice confinement were the major parameters considered. Performance was judged on the basis of strength, ductility, and several degradation indicators.Behavior was dependent on the degree of splice confinement. Specimens containing superior splice confinement, provided either by closely spaced stirrups or by closely fitting spirals, were more ductile and sustained more load cycles, on average, prior to failure. It was advantageous to provide more splice confinement than the amount considered to be effective under static loading. Tensile splices designed with superior confinement according to proposed seismic specifications achieved ductility ratios (failure deflection divided by first yield deflection with no splice) which averaged 2.66.Reversed cyclic loading was more damaging than repeated unidirectional or monotonic loading. The number of reversed load cycles to failure decreased as the intensity of loading increased. Under load reversals, the reduction in stiffness, the increase in energy dissipation, and the gain in damping capacity were used to examine the degradation that could be sustained before failure. Key words: reinforced concrete, beams, bond, splices, cyclic loads, ductility, seismic design, joints, deflection, strength, stiffness, damping.
Experimental investigation of steel fiber-reinforced concrete beams under cyclic loading
