Influence of shape modification and stirrups on the axial capacity of concrete columns

Columns as an important element of building structures support loads that work on slabs and beams and deliver the loads to the foundation. Concrete columns can experience strength degradation due to several reasons such as having less concrete strength than designed due to construction error or environmental damage. To restore the strength capacity of the columns, rehabilitation or retrofitting methods with steel plates or Fibre-Reinforced-Polymer (FRP) sheets are generally applied. This method is effective if the shape of the column is rounded. However, the shape of the column in the field is commonly rectangular or squared. Moreover, retrofitting using FRP is very expensive. Based on this background, this study examined the effect of shape modification and stirrup on the axial capacity of concrete columns. A total of 12 specimens of concrete columns were cast and tested. The specimens were grouped into 4, with variations in shape and stirrup spacing. The experimental results showed that the shape modification increased the axial capacity of the concrete column. Shape modification and addition of stirrups at the same time increased the axial capacity of the concrete columns more significantly. Furthermore, the shape modification and addition of stirrups improved the performance of the columns