The Effect of Section Enlargement with Cementitious Grout on the Eccentric Compression Behavior of RC Columns

The use of cementitious grout to enlarge the member size represents a method for strengthening RC columns, addressing limitations inherent in traditional section enlargement techniques. This study conducted experiments on the eccentric compression behavior of RC columns reinforced by enlarging the member size through the application of cementitious grout. The effects of eccentricity, strengthening thickness, new steel bars, and strengthening position on the bearing capacity of columns strengthened with cementitious grout were investigated. The results show that increasing the size of the members with cementitious grout can significantly improve the bearing capacity of columns under eccentric loads, with improvement ranging from 16% to 237%. Strengthening in the compression zone had a notably greater impact compared to strengthening in the tension zone for eccentric compression members. The ultimate compressive load of the strengthened columns experienced varying degrees of improvement with the increase in strengthening thickness and area of new steel bars. In addition, the study established a calculation formula for the bearing capacity of a strengthened column under eccentric load based on the plane section assumption and verified the availability of the calculation method by comparing the calculation results with the experimental results.