DEVELOPMENT/SPLICE LENGTH OF REINFORCING BARS

This article discusses the effect of different parameters on the bond strength and ductility of beams. The authors present an equation to calculate the required development/splice length of reinforcing bars. The equation is based on previous studies on bond between normal-strength concrete (NSC) and high-strength concrete (HSC) and reinforcing bars. The authors note that the new reinforcing bars with improved bond strength and the new proposed models to calculate the development/splice length will result in the reduction of steel bars in structural members, especially in the congested beam-column joints of concrete structures. Based on the proposed equation, a simple equation to predict the splice/development length of embedded bars is derived. The authors also introduce a new parameter to account for the effect of transverse reinforcement (TR) on bond strength. The authors report the comparison between the results of 284 available tests in cases of NSC and HSC; the new proposed model correlates very well with the test results. The proposed bond strength equation can also accurately account for the rib properties of the reinforcing bars on bond strength.