Retrofitting of reinforced concrete columns under eccentric loads using enhanced ferrocement

Abstract

Reinforced concrete columns are the most important load-bearing structural components in the buildings. These columns require retrofitting due to multiple reasons like poor design, inadequate materials, weak construction and improper quality control. This research involves retrofitting of reinforced concrete columns subjected to biaxial loads by using of enhanced ferrocement jacketing. Fifteen reinforced concrete columns are cast in 150 × 150 × 1700 mm including 250 × 250 × 250 mm concrete brackets at each end. They divided into three groups each with four columns in addition to the three control specimens. The three groups are preloaded up to 65 and 85% of the total failure loads of control specimens. After that, the first group retrofitted using traditional ferrocement consists of normal cement-sand mortar and reinforced with steel wire mesh. The second group retrofitted with modified mortar and steel wire mesh reinforcement. While the third group of columns retrofitted with modified mortar and reinforced with fiber glass mesh. All the columns are then biaxially loaded till failure with two different eccentricity values 30 and 70 mm. The results show that using enhanced ferrocement jacketing increases the load carrying capacity of retrofitted columns comparing to the control specimens with different percent of enhancement up to 30.6% for the column retrofitted with modified mortar and fiber glass mesh. Also, it develops the failure behavior, ductility ratio and cracks resistance of the retrofitted columns.