Discussion of “Alternative Shear Reinforcement of Reinforced Concrete Flat Slabs” by K. Pilakoutas and X. Li

Abstract

This brief article comments on a paper that presented a series of validation tests for a patented shear reinforcement system for reinforced concrete (RC) flat slabs (Pilakoutas and Li, September 2003). The system, called Shearband, consists of elongated thin steel strips punched with holes, which undulate into the slab from the top surface. The main advantages of the new reinforcement system are structural effectiveness, flexibility, simplicity, and speed of construction. Four RC slabs were tested in a specially designed test rig. The paper reviewed existing types of shear reinforcement and identified the need for more efficient, economic solutions. The authors concluded that the system enabled the slabs to avoid punching shear failure and achieve their flexural potential. In this commentary, the authors contend that the concrete strength of the control specimen in the study is considerably smaller than the specimens with shearbands. The discussers believe that shearbands, installed as proposed for construction, will have poor anchorage and contribute little to the punching shear strength. They conclude that the shearbands are not practical: they do not satisfy the ACI 318-02 code anchorage requirement and the experimental investigation presented in the paper does not show that they are effective.