The retrofit of non-slender square concrete column with an external strengthener of carbon fiber-reinforced polymer (CFRP) under the influence of cyclic load. The purpose of this study is to know the increase of strength and ductility of a column structure element that has an initial damage, then it is fixed and strengthened by CFRP external strengthening. The column structure element is tested by giving a constant axial load and varying the cyclic load using a displacement control. In this research, two specimens t are used, C-1 column (original column) and C-1RC column (retrofit column). The results of the study show that (1) the effectiveness of the C-1CR’s restraint and moment of force are increased by 1.58 times and 52.78% compared to the C-1’s ones, and (2) the installation of CFRP reinforcement increases the strength in accepting lateral load by 52.15% and decreases of ductility by 52.12%. Tujuan penelitian ini mengetahui peningkatan kekuatan dan daktilitas elemen struktur kolom yang mengalami kerusakan awal, kemudian diperbaiki, dan diperkuat dengan perkuatan eksternal carbon fiber-reinforced polymer (CFRP). Pengujian terhadap elemen struktur kolom dilakukan dengan memberikan beban aksial yang konstan dan memvariasikan beban siklik dengan kontrol perpindahan. Dalam penelitian ini digunakan dua spesimen yaitu kolom C-1 (kolom original) dan kolom C-1RC (kolom retrofit). Hasil penelitian menunjukkan (1) efektifitas pengekangan C-1CR meningkat 1,58 kali dan kekuatan terhadap momen meningkat sebesar 52,78% dibanding kolom C-1, dan (2) pemasangan perkuatan CFRP memberikan peningkatan kekuatan dalam menerima beban lateral sebesar 52,15% dan penurunan daktilitas sebesar -52,12%
