內灌混凝土鋼柱與鋼骨鋼筋混凝土梁或鋼筋混凝土梁之子構架耐震行為

Abstract

本研究探討鋼骨鋼筋混凝土柱與鋼骨鋼筋混凝土梁與鋼骨鋼筋混凝土梁及鋼筋混凝土梁接頭之耐震行為，主要試驗參數包括寬厚比、斷面配置以及接頭細部設計，共四組試體。試驗方法為施加側力對試體進行位移控制之反復載重試驗，試體製作使用SN 490B系列之鋼材、混凝土抗壓強度為35 MPa及SD420W系列之鋼筋。具10 cm厚混凝土之包覆填充型箱型鋼柱其鋼骨斷面為Box 495x495x19 mm，寬厚比為24.1，滿足美國AISC對於高韌性構件的斷面限制(λhd = 33.6)，也滿足台灣規範對於塑性斷面設計之限制(λpd = 43.1)；試體一為鋼骨鋼筋混凝土梁，其鋼梁斷面滿足台灣規範對於塑性斷面設計之限制；試體二為鋼筋混凝土梁，內部設計一30 cm長之剪力板作為剪力傳遞機制；試體三為鋼筋混凝土梁，內部設計一30 cm長之鋼短梁作為彎矩及剪力傳遞機制；為探討鋼短梁長度對耐震行為之影響，設計試體四為鋼筋混凝土梁，內部接110 cm長之鋼短梁作為彎矩及剪力傳遞機制。 試驗結果顯示，試體一、試體三及試體四在層間側位移角0.04 rad之前，試體皆保持完整無明顯破壞，試體二於層間側位移角0.02 rad即因續接器銲道破壞造成試驗終止。試體一之鋼梁上翼板於層間側位移角0.04 rad負迴圈第一圈時斷裂，顯示SRC梁更應該採用RBS韌性削切以達到接頭之韌性需求。試體二藉由剪力板傳遞剪力之設計未達預期效果，使續接器於反復載重過程中同時受剪力及拉力，且銲道有瑕疵的情況下造成柱面與續接器銲道破壞。試體三於試驗過程中無明顯破壞，滿足AISC 341-16於層間側位移角0.04 rad第一迴圈至少滿足0.8Mp(Mn)之接頭耐震規定，但試體於轉換斷面有明顯相對滑移產生。試體四亦滿足前述AISC規範規定，但轉換斷面於層間側位移角0.04 rad第二迴圈時有更嚴重之梁相對滑移以及混凝土剝落。顯示鋼短梁是比剪力板還要好的傳力機制，然而SRC與RC構材間之轉換續接有待更好的設計及改良。

This study investigates the seismic behavior of steel reinforced concrete columns between steel reinforced concrete beams and reinforced concrete beams.The main test parameters include width-to-thickness ratio, section configuration, and joint detailing, with a total of four groups of specimens. The experimental method involves applying lateral forces to the specimens and subjecting them to displacement-controlled cyclic loading tests. The specimens are fabricated using steel materials from the SN 490B series, concrete with a compressive strength of 35 MPa, and steel reinforcement from the SD420W series. The steel section of the concrete-filled box steel column, with a 10 cm thick concrete enclosure, has a cross-sectional shape of Box 495x495x19 mm. Its width-to-thickness ratio is 24.1, which satisfies the section restrictions for high ductility members according to the American Institute of Steel Construction (AISC) with a limit of λhd = 33.6. Additionally, it meets the requirements for plastic design stipulated by Taiwanese regulations with a limit of λpd = 43.1. Specimen 1 is a steel reinforced concrete beam, and its steel beam section complies with the plastic design requirements stipulated by Taiwanese regulations. Specimen 2 is a reinforced concrete beam with a 30 cm long shear plate for shear transfer mechanism. Specimen 3 is a reinforced concrete beam with a 30 cm long steel short beam for both bending and shear transfer mechanism.To investigate the effect of the length of the steel short beam on seismic behavior, a specimen is designed with a 110 cm long steel short beam for both bending and shear transfer mechanism. The test results indicate that specimens 1, 3, and 4 maintained integrity without significant damage until a drift angle of 0.04 radians. Specimen 2 was terminated due to weld failure of the couplers at a drift angle of 0.02 radians. The failure of the upper flange of the steel beam in specimen 1 at the first cycle of the negative loop at 0.04 rad drift indicates the need for a more ductile joint design for SRC beams, such as the reduced beam section (RBS) method. Specimen 2 failed to achieve the expected effect of shear transfer through the shear plate design, leading to simultaneous shear and tension on the couplers during cyclic loading, exacerbating the weld defects and resulting in weld failure between the column face and couplers. Specimen 3 showed no significant damage during testing, satisfying the seismic requirements of AISC 341-16 at a drift angle of 0.04 radians for the first loop with at least 0.8Mp (Mn) capacity. However, significant relative slip occurred at the transformed section. Specimen 4 also met the seismic requirements of AISC, but exhibited more severe relative slip and concrete spalling at the transformed section during the second loop at a 0.04 rad drift. This indicates that the steel short beam is a better transfer mechanism than the shear plate, but there is room for improvement in the design and detailing of the transition joints between SRC and RC members.