DUCTILITY OF CONTINUOUSLY CONFINED COLUMNS UNDER HIGH-AXIAL LOADING

• Main Authors: Mario D.Barahona, 羅漢哲
• Other Authors: Tsung-Chin Hou
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/arefr3

碩士 === 國立成功大學 === 土木工程學系 === 107 === Columns are structural elements that are prone to failure during intense earthquakes. Transverse reinforcement helps to prevent buckling of the longitudinal bars, prevents shear failure, and confines the concrete core. The bars have to be cut, bent and then placed individually on their corresponding position by the workers. All these complex details are sometimes difficult to accomplish on-site and might lead to construction errors. Due to technological advances and the automation of construction processes, some authors have proposed the use of continuous rectangular spirals for transverse reinforcement using machines that can be configured to obtain rebars bent to any desired shape and pitch. In this study, the use of two continuous rectangular spirals is proposed, one along the corner longitudinal bars, and a second one holding the inner longitudinal bars. The use of two independent spirals may provide more adequate ductility and confinement of the core concrete. Three columns were tested in order to evaluate their seismic performance, comparing the ductility, failure mode, and hysteretic behavior at different drift ratios of the specimens reinforced using spiral transverse reinforcement against a specimen reinforced with conventional ties. The test variables were the transverse reinforcement configuration and the effects of welding the spirals to the longitudinal steel reinforcement. The results indicate that using continuous transverse reinforcement provides several benefits. The use of rectangular spirals ease the construction process and it demands fewer amounts of steel. Their seismic performance is satisfactory and provides better confinement when an element is subjected to high-axial loading.