Bond-slip behavior of large high-strength concrete-filled circular steel tubes with different constructions

摘要

To investigate the bond-slip behavior of the interlace in large high-strength concrete-filled circular steel tubes (HSCFCSTs), 18 specimens with 6 different constructions (HSCFCSTs with no additional construction, with built-in studs, with built-in circular ribs, with built-in vertical ribs, and with various combinations of the above) were examined using push-out tests. Specimens were constructed from high-strength concrete or recycled aggregate concrete (RAC). The bond-slip behavior and slip-failure mechanisms were analyzed through comparison of load-slip curves, slip displacements, and steel tube strain to generate predicted load-slip curves based on multiple parameters. Experiments revealed that the bond-slip curves of HSCFCSTs with no additional constructions contained an ascending section, a rapidly descending section, and a residual section. For tubes with special constructions, the descending section was either postponed or not visible, the interfacial bonding properties were enhanced when using special constructions, the concrete strength and bond strength were positively correlated, and the RAC had better bonding behavior than normal concrete. The predicted load-slip curves agreed with the test curves and provided a theoretical basis for HSCFCST applications. (C) 2020 Elsevier Ltd. All rights reserved.