Confinement of reinforced-concrete columns with non- code compliant confining reinforcement plus supplemental pen-binder

One of the important requirements for earthquake resistant building related to confinement is the use of seismic hooks in the hoop or confining reinforcement of reinforced-concrete column elements. however,installation of a confining reinforcement with a 135-degree hook is not easy. therefore,in practice,many construction workers apply a confining reinforcement with a 90- degreehook (non-code compliant). based on research and records of recent earthquakes in indonesia,the use of a non-code compliant confining reinforcement for concrete columns produces structures with poor seismic performance. this paper presents a study that introduces an additional element that is expected to improve the effectiveness of concrete columns confined with a non-code compliant confining reinforcement. the additional element,named a pen-binder,is used to keep the non-code compliant confining reinforcement in place. the effectiveness of this element under pure axial concentric loading was investigatedcomprehensively.the specimens tested in this study were 18 concrete columns,with a cross-section of 170 mm x 170 mm and a height of 480 mm. the main test variables were the material type of the pen-binder,the angle of the hook,and the confining reinforcement configuration.the test results indicate that adding pen-binders can effectively improve the strength and ductility of the column specimens confined with a non-code compliant confining reinforcement. © 2012 published by lppm itb.