Pada umumnya kolom mendukung beban aksial secara eksentris. Eksentrisitas kolom berpengaruh terhadap stabilitas struktur kolom dan pola keruntuhan struktur. Penelitian ini bertujuan untuk mengetahui pengaruh metode perbaikan dengan sistem jacketing terhadap kekuatan, kekakuan, daktilitas, pola retak dan model keruntuhan. Benda uji berupa kolom pendek beton bertulang penampang persegi dan dibebani dengan beban tekan aksial eksentris. Pada penelitian ini digunakan 3 buah benda uji kolom berpenampang persegi dengan dimensi 150 mm x 150 mm, tinggi efektif 600 mm dengan tulangan longitudinal 4∅12 dan sengkang ∅8-150. Ketiga kolom tersebut memiliki eksentrisitas tetap sebesar 112,5mm (0,75 h). Ketiga kolom diuji dengan beban aksial sampai mencapai beban aksial maksimumnya dan rusak. Benda uji kolom yang rusak kemudian dikupas selimut betonnya, lalu bungkus dengan wiremesh dan dicor selimut beton yang baru serta diuji kembali. Penampang kolom yang telah diretrofit ini menjadi 220 x 220 mm. Pengujian kolom retrofit diuji kembali dengan cara pembebanan yang sama sampai runtuh. Kolom dengan eksentrisitas 112,5mm (0,75h), kapasitas beban maksimum setelah diperbaiki menunjukkan peningkatan 150%, 143,63%, dan 190,28% dengan diameter wiremesh berturut-turut 3mm, 4mm, dan 5mm relatif terhadap kolom aslinya. Daktilitas kolom retrofit dengan diameter wiremesh 4mm, meningkat 10,11% relatif terhadap kolom retrofit dengan diameter wiremesh 3mm, tetapi daktilitas kolom retrofit dengan diameter wiremesh 5mm, mengalami penurunan 23,24% relatif terhadap kolom retrofit dengan diameter wiremesh 3mm. Kekakuan dari kolom retrofit dengan diameter wiremesh 4mm dan diameter wiremesh 5mm mengalami peningkatan 50% dan 654,09% relatif terhadap kolom retrofit dengan diameter wiremesh 3mm. Semua kolom menunjukkan pola yang sama yakni keruntuhan tarik. Model keruntuhan kolom diawali munculnya retak awal pada sisi tarik yang melebar dan memanjang seiiring peningkatan beban, kemudian terjadi spalling pada sisi tekan.

In general, a column supports load eccentrically. Column eccentricity affects column stability and also the collapse mechanism of a building structure. The objective of this research is to study the influence of retrofitting method by jacketing on strength, stiffness, ductility, cracking pattern, and failure mechanism of column. The specimen was rectangular short column loaded axially under a given eccentricity. This research used 3 specimens columns having rectangular cross section of 150 x 150 mm, effective height 600 mms, and reinforced with 4∅12 mm longitudinal steel bars and ∅8-150 mm stirrup. All columns had a constant eccentricity of 112,5 mm (0,75h). They were loaded gradually until its maximum capacity and damaged. The damaged column was repaired. Its concrete cover was peeled off, wrapped with wiremesh reinforcement of various diameter and cast with concrete. The cross section of the retrofitted columns became 220 x 220 mm and tested under similar loading pattern as those of original column. With load eccentricity of 112,5 mm, the maximum load capacity after repaired, exhibited increased 150%, 143,63% and 190,28% for wiremesh diameter of 3, 4, and 5 mm, respectively of the original column. The ductility of retrofitted column with diameter 4 mm increase respectively 10,11% compared to retrofitted column with diameter 3 mm but the ductility of retrofitted column with diameter 5 mm decrease respectively 23,24% compared to retrofitted column with diameter 3 mm. The stiffness of retrofitted column with diameter 4 and 5 mm increase respectively 50% and 654,09% compared to retrofitted column with diameter 3 mm. Cracking pattern of the column after and pre retrofitted, in general, follow similar pattern horizontal at tension side of the column. All columns exhibited modes of failure that were similar to the tension failure. The modes of failure was started by hairlines crack appeared at tension side followed by the widening and elongating of several crack as the load increased, and finally concrete spalled off from the concrete surface at compression side.

Kata Kunci : Kolom pendek,Kolom penampang persegi,Kolom retrofit,Kawat wiremesh,Kapasitas beban maksimum, Short column, rectangular cross section column, retrofitted column, wiremesh, maximum load capacity, ductility, stiffness