Experimental Research and Numerical Analysis on the Concrete-Filled Square CFRP Steel Tube Column Under Compressive-Shear Loading

A large number of concrete-filled CFRP steel tube structures are widely used in practical engineering at current. Considering that as a column structure, compressive-shear loading is a more important bearing capacity method. 12 specimens are designed to study the comperssive-shear performance of concrete filled CFRP steel tube. The shear loading- displacement (V-Δ) curves and the collaborative work performance between the steel tube and CFRP are tested. Based on the tests, a numerical simulation method is firstly proposed to estimate the compressive-shear performance of concrete-filled CFRP steel tube stub column, and then validated against the representative tests results.Parametric study is conducted to explore the influence of principle factors on compresive-shear behaviour by verified numerical models. The experimental results show that the steel tube and CFRP can work together. As the axial compression ratio increases, the shear displacement of the specimen is constrained, resulting in increase of bearing capacity. Additionally, the increase of steel ratio, CFRP layers and materials strength for specimens enhance not only the bearing capacity but also the initial stiffness. The simulation results of the established finite element model are in good agreement with the experimental results. Finally, Based on experimental and finite element results, the bearing capacity correlation equation for concrete-filled square CFRP steel tublar stub columns when subjected to compressive-shear loading is presented.