Bond Behavior in Steel Fiber-Reinforced Concrete Zones under Static and Cyclic Loading: Experimental Evaluations and Analytical Modeling

Abstract

There is a renewed interest in using steel fiber reinforcement within the critical hinging regions of reinforced concrete (RC) members as a means for improving their seismic response. Examples include beam-column joints, structural walls, and shear walls coupling beams. The presence of steel fiber reinforcement in these regions confines the concrete, improves the bond strength of the steel bars, and reduces the bond degradation, leading to reduced damage and increased energy absorption and dissipation capacities under cyclic loading. This paper presents a synthesis of the results of a series of experimental and analytical investigations undertaken by the writer on the use of steel fiber reinforcement for improving the bond capacity and bond stress-slip response of steel bars under static and cyclic loading and its implication on the static and seismic response of RC members. The experimental results are discussed, a design expression for evaluating the effect of fiber reinforcement on the bond or development/splice strength of steel bars in tension is described, and a new model of the local bond stress-slip response under generalized (cyclic) excitations is presented.