Seismic Behavior of Headed-Bars in High-Strength RC Exterior Beam-Column Joints with P-Delta Effect

• Main Authors: Wei-Fan Chao, 趙偉帆
• Other Authors: Chien-Kuo Chiu
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/54841222274884637001

碩士 === 國立臺灣科技大學 === 營建工程系 === 104 === In the moment resisting frames, impacts of gravity effect and dumping moment of earthquakes on the entire building cause the axial force that exterior beam-column joints bear to vary depending on the direction and size of the dumping moment. As a result, the axial force variation of columns and impacts of horizontal displacement δ on shears should be taken into consideration, while evaluating the seismic capacity and deformation behavior of beam-column joints. In traditional RC exterior beam-column joints, beams are typically anchored in columns at a 90º angle. However, since the SD685 steel rebars adopted in New RC are enhanced with higher strength, the rebars are not vulnerable to bending, and thus standard hooks are not recommended for use. This study adopted nuts of head as the anchorage device of threaded-reinforcement, aiming to verify if the anchored length that complies with ACI 318-14 requirements can be applied to Taiwan’s New RC structures. This study carried out four tests on exterior beam-column joints in total, targeting on exploring if the material strength of the New RC structures is in compliance with the ACI 318 requirements, including the maximum strength of steel reinforcement bars and concrete materials, the clear spacing of headed bars, the development of reinforcement, and the shear zone demand and capacity ratio of beam-column joints in intersection areas. The columns are also observed to explore if secondary moment happens under P-δ Effect and the impacts on the strength of joints. Moreover, the study made a comparison between the test methods of push columns and the forms of traditional push beams to explore the consistency of both behaviors.