Investigation on Behavior of Strengthened Beams by CFRP in Adjacency of Columns

There are numerous methods for strengthening concrete structures in which using fiber-reinforced polymers (FRP) is suitable for retrofitting reinforced concrete (RC) structures. In RC frames, maximum negative moment of beam occurs at the junction point. Continuing FRP from beam to the face of column (‘L’ shaped) in negative moment zone and then wrapping the column are widely used to anchor longitudinal FRP. Reviewing the findings shows that few studies have been conducted in this area. So, in this study with the construction of four RC specimens (‘+’ shaped ( and strengthening of beam in adjacency of column, the effect of this type of anchorage has been evaluated. One specimen acts as a control specimen (non-strengthened) and three others were strengthened by one, two and three layers of CFRP sheets in tension side. In order to anchor longitudinal CFRP sheet, these sheets were continued and wrapped on column. All the specimens were loaded under concentrated load at midspan (i.e. on the column). The experimental results demonstrate that the yield load of tensile steel of strengthened specimens is slightly increased and also the crack width of strengthened specimens is reduced in comparing with control specimen. But increasing ultimate load capacity of strengthened specimens is very lower in comparison with expected values. Therefore, this type of anchorage is not effective for strengthening of RC beams in adjacency of columns.