TENSILE LAP SPLICES IN REINFORCED-CONCRETE BEAMS UNDER INELASTIC CYCLIC LOADING

Two sizes of concrete beams containing lap splices were tested under full-reversal inelastic cyclic loading to evaluate design recommendations for seismic loading proposed by researchers at Cornell University. Two-point symmetrical loading produced tensile yielding in the lap splices located at midspan. In addition to beam size, variables included the influence of the actual yield strength of the specified Grade 400 MPa main reinforcement. Reasonable ductility was found for beams with splices designed according to the Cornell proposals for seismic loading, provided the actual yield strength of the main reinforcement was close to the specified (nominal) yield strength. However, overstrength reinforcing steel (still within the strength limits for seismic design) was detrimental for beam ductility, requiring the actual, rather than specified, yield strength to be used for proportioning the splice to insure reasonable performance.