EFFECTS OF DEBONDING ON AXIAL-LOADED CIRCULAR CFST COLUMNS WITH DIFFERENT SLENDERNESS RATIOS

With the rapid development of the economy in China, numerous CFST bridges have been built in recent years. The CFST arch bridges have become a viable alternative to reinforced concrete (RC) arch bridges or steel arch bridges due to several advantages. One of the most important advantages is the confinement effect of core concrete from steel tube under compression. However, this beneficial composite action will be probably weakened by debonding, which is almost unavoidable as a common phenomenon in CFST structures. In this paper, the finite element models of debonding circular CFST columns with different slenderness ratios were implemented using the finite element software ABAQUS, and the validity and accuracy of the results were verified by test results of debonding CFST stub columns. Utilizing the finite element model, a parametric analysis was carried out to study the influence of the following parameters on the ultimate load capacity of debonding specimens: debonding arc-length ratio, debonding thickness, confinement factor and slenderness ratio. Based on the results of parametric analysis, a simplified calculation formula was proposed to calculate the ultimate load capacity of debonding circular CFST columns subjected to axial load.