Improving the strength and ductility of rectangular reinforced concrete columns through composite partial interaction: Tests

A new structural approach that uses composite partial interaction to improve the strength and ductility of rectangular reinforced concrete columns has been studied experimentally. By increasing the compressive resistance of concrete columns, through composite partial interaction such as by bolting a steel plate to the compression face of a column, this new composite action approach is shown to successfully delay concrete crushing in the plastic hinge zone. The experimental results confirm theoretical predictions that composite partial interaction can be used to increase either the strength or ductility (or both) of concrete columns. The paper also briefly describes a design procedure for the retrofit strategy to achieve a specified displacement, or interstory drift.