鋼梁接圓形鋼管混凝土柱接頭耐震行為

Abstract

鋼管混凝土具有高強度、高勁度與韌性佳之優點，但其梁柱接頭細節不易設計，往往需要大量銲接方能達到設計要求。因此本研究設計一夾型板式接頭，其夾型鋼板貫穿鋼管並以開槽銲與鋼管接合，夾型鋼板延伸出柱面段則與鋼梁填角銲接合。藉由夾型鋼板貫穿鋼管將梁翼應力傳導入交會區，避免梁柱交接面應力集中；夾型鋼板自柱面延長段補強梁翼斷面，並於延長段末端形成塑鉸消散地震能量。 本文進行四組實尺寸梁柱接頭試驗，其中兩組試體設計為強柱弱梁，預期非彈性變形集中於夾型板末端塑鉸處，另兩組試體設計為低交會區剪力強度，預期非彈性變形集中於夾型板末端塑鉸處與梁柱交會區。實驗結果顯示夾型板式接頭可有效傳遞梁翼作用力至交會區。本研究採用軟化壓桿理論與混凝土圍束效應所提出交會區剪力強度預測理論，可有效預測夾型板式梁柱接頭交會區剪力強度。

Concrete-filled tube (CFT) columns possess several structural advantages such as stiffness, strength, and ductility. However, it is difficult to joint the steel beam to the circular CFT column due to its complexity. This research proposed a connection detail, which is by penetrating a pair of clamping plates through the tube and welding to the steel beam. The force-transferred mechanism of the connection is established by transferring the beam flange forces into the tube and concrete core through those clamping plates. Four large-scale specimens were designed and fabricated to identify the possible failure mode. Test results indicate that the penetrated clamping plate connections possess the satisfactory connection strength and inelastic deformation ability required for the moment connection when the shear strength in the joint is adequately designed. Joint shear failure, presented by the shear cracking on the concrete inside the tube, is the controlled mode of failure for the flange plate connection with weak joint shear strength. The clamping plates are effective to transfer the beam flange forces into the concrete core. Proposed softened strut-and-tie model can predict the joint shear strength well.