Abstract
This paper presents a trilinear restoring force model based on the test results of two square concrete-filled steel tubular (CFT) stub columns without binding bars and eight square CFT stub columns with binding bars subjected to constant axial load and cyclic lateral load. The effects of binding bars and axial load level on the specimens are considered to determine the feature points of the skeleton curves. Calculation formulas for the characteristic parameters of the model, including the yield load, the peak load and the ultimate load, are given by analyzing the influence of the confinement factor of steel tube, the confinement coefficient of binding bars and the axial load level. Additionally, the hysteretic rule under cyclic lateral load is confirmed. The predicted hysteretic cures and skeleton curves based on the proposed model are in good agreement with the experimental results.
Highlights
A simplified restoring force model, including the skeleton curve and hysteretic rule, for the square Concrete-filled steel tubular (CFT) columns with binding bars was proposed based on the theoretical model and
The results show that the binding bars can improve the strength capacity of square CFT columns
Ck s s ck c where ξ is the confinement coefficient of steel tube; ξ is the confinement coefficient of binding bars; B is the width of square steel tube; t is the wall thickness of steel tube; as and bs are the horizontal and longitudinal spacing between binding bars respectively; fy and fay are the yield strength of binding bars and steel tube respectively; fck is the characteristic strength of core concrete, defined as 0.76fcu, and fcu is the cubic compressive strength of core concrete; Aa and Ac are the area of steel tube and core concrete on the cross section respectively; As is the area of binding bar
Summary
Ten square CFT columns, including 8 columns with binding bars and 2 columns without binding bars were designed and tested subjected to constant axial load and cyclic lateral load. All the specimens were made of square steel tube with the width of 200mm in cross-section and 600mm in height. The thickness of steel tube is 6mm. The diameter of binding bars is 10mm. The material properties of core concrete, steel tube and binding bars are listed, respectively. The experimental parameters are the axial load level, the horizontal spacing of binding bars and the longitudinal spacing of binding bars. (1) shows the details of the cross section of specimens. The configurations of binding bars are given in Fig. All the specimens were tested under a constant axial load and cyclic lateral load. The configuration for all specimens is shown in Fig. The configuration for all specimens is shown in Fig. (2)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
