摘要：Abstract The aim of this work is to study the effect of partial strengthening of partially defected columns on its capacity, and global behavior. There are two types of defects on R.C columns, the first is decreasing the characteristic compressive strength of a part of R.C column, and the second is bad stirrup arrangement. External FRP jacketing and steel jacketing have been widely used for strengthening R.C columns. The cost effectiveness and convince of applying the steel jacketing strengthening technique have been demonstrated through various strengthening applications. Few studies have been carried out on partial strengthening of defected columns. In this research, the efficiency of short steel jackets for strengthening of R.C defected columns was studied. The experimental program consists of testing of seven R.C columns with dimensions 200*200*1500mm and having stirrups in top and bottom thirds only, while the middle third was without stirrups. The main parameters studied were the type of steel jacket used and height of partial strengthened part of column. One of the tested specimens was a control specimen and the other six were partially strengthened with different types of steel jackets such as using 4 steel angles at corners connected with straps, using external ties with different spacings, and using 4 steel plates with different thicknesses welded together and connected to column by anchor bolts. Finally, the experimental results were analyzed and compared with results obtained from finite element analysis using ANSYS program.
