Results from cyclic tests on high aspect ratio RC columns strengthened with FRP systems

A limited number of experimental studies have been performed on FRP-confined columns having rectangular cross section with high aspect ratio.The experimental study presented herein addresses this knowledge gap by investigating performances, under constant axial load and cyclically reversed horizontal force, of full scale rectangular (300 × 700 mm) RC columns externally confined by using Fiber Reinforced Polymers (FRPs) or strengthened with FRP wraps and steel profiles. The study is a part of a wider experimental campaign also including tests on square (300 × 300 mm) columns whose details have been already published elsewhere.Test results discussed herein aim to evaluate the influence on the column performance of relevant parameters, such as: unconfined concrete strength, longitudinal steel reinforcement (smooth or deformed rebars), strengthening system (FRP confinement with or without steel profiles); axial load level and number of FRP layers. Finally, the effectiveness of the used strengthening techniques is investigated through the comparison with the performances obtained in the case of square members.

► Experimental tests on full scale RC 300 × 700 mm rectangular columns are presented.
► Performances of different strengthening techniques with FRP materials are discussed.
► It is shown that the FRP confinement significantly increases the columns ductility.
► The combined use of FRP confinement and steel angles also improves the flexural strength.
► The FRP confinement increases the cumulative dissipated energy of columns.