The Behavior and Design of Noncontact Lap Splices Subjected to Repeated Inelastic Tensile Loading

Keywords: Structural Dynamics, Steel Frames, Reinforced Concrete, Seismic Loading, and Dynamic Response.

Abstract: The results of an investigation on the behavior and design of noncontact lap splices under monotonic and repeated inelastic loading is presented. This is the final phase of an extensive investigation on the behavior of lap splices subjected to inelastic cyclic loading. The goal of the study is to understand the behavior of noncontact tensile lap splices and to formulate improved design guidelines and equations that conform to existing unified design equations. Forty-seven full-scale, flat plate tension specimens were tested to determine the effects of specimen geometry, bar size, concrete strength, splice length, transverse steel area and spacing, repeatability, and primarily, the spacing of the splice bars. The test data and other literature suggest that the load transfer between two bars of the splice is by a truss-like mechanism. The failure mode is an in-plane crack produced by a combination of bond-induced bursting forces and Poisson strain produced by the in-plane compressive stresses. The behavior is influenced by the added confinement that comes from spacing of the splice bars, and the reduction in concrete tensile strength with the compression field of the force transfer that is needed to resist the bursting. Equations for the design of noncontact lap splices for both monotonic and seismic loading are derived that take into account these effects, and are modifications of existing state-of-the-art lap splice design equations.