Experimental study on influence of proposed FRP-strengthening techniques on RC circular short columns considering different types of damage index

摘要

The most important phenomenon that threatens the stability and health of structures in different parts of the world is the occurrence of an earthquake with varying intensity and magnitude. The most dangerous type of failure in structures is shear failure, which could occur in short columns. Consequently, such columns, with the potential of failure in shear, must be retrofitted. This paper explores three new methods for strengthening RC circular short columns, including the Near Surface Mounted (NSM), externally bonded with new pattern and an innovative hybrid strengthening technique (using near-surface mounted method in the form of spiral grooves filled with CFRP hand-made bar in composition with externally bonded CFRP sheet) and compare them with two common methods of strengthening (full and partial wrapping). Six circular short columns were constructed, strengthened and tested under constant axial load and cyclic lateral loading. An analytical procedure was used to predict the behavior of the columns. A good correlation was observed between analytical values and experimental results. An innovative hybrid strengthening method and externally bonded method with new pattern showed higher values in strength, energy absorption, ductility and stiffness compared to existing methods.