Prediction of the Effective Concrete Strength for Column-Slab Connections

For cases where the column concrete strength exceeds 1.4 times the slab concrete strength, the KCI Code requires that either: puddled high-strength concrete(HSC) be used in the slab, or the use of vertical dowels and spirals through the joint, or the use of an effective concrete strength in the joint. This paper studies on the third strategy. A prediction model of the effective concrete strength for interior columns was proposed using an analogy of brick and mortar in brick masonry. The proposed prediction model is verified by comparison with experimental results and various design equations.