Analysis and design of axially loaded square CFST columns with diagonal ribs: Fid-Bau Portal

Analysis and design of axially loaded square CFST columns with diagonal ribs

Zhou, Xuhong / Zhou, Zheng / Gan, Dan

Abstract Diagonal binding ribs, made of thin-walled steel plates with circular openings and welded to the steel tube of a square concrete-filled steel tubular (CFST) column, can improve the composite effect effectively by co-carrying axial compressive forces and confining the steel tube and concrete. The column with diagonal ribs is referred to as diagonal ribs stiffened CFST column. This paper summarizes the test results of axially loaded diagonal ribs stiffened and longitudinal ribs stiffened CFST columns comprehensively, followed by further tests of stub columns with longitudinal reinforcing bars. A verified finite element analysis (FEA) model was presented to implement parametric studies. The studied parameters included diagonal rib detailing (i.e., opening diameter, opening spacing, and welding position) and material strengths. Finally, based on the test and analysis results, design considerations, involving width-to-thickness ratio limits of tube plates, diagonal rib detailing, thickness matching relationship between diagonal ribs and the steel tube, detailing of composite column with diagonal ribs, and load-carrying capacity prediction, were proposed.

Highlights • Diagonal binding ribs significantly improved composite response of CFST columns. • Design considerations for the diagonal ribs stiffened square CFST column were proposed. • Test results about stiffened square CFST columns were summarized and analyzed comprehensively. • A verified finite element analysis model was presented to implement parametric studies.