Axial Load Behavior of Rectangular CFT Stub Columns with Binding Bars

This paper presents an experimental study on the axial load behaviour of rectangular concrete-filled steel tubular (R-CFT) stub columns with binding bars. Eight specimens were concentrically loaded in compression to failure in order to investigate the effects of the binding bars, depth-to-wall thickness ratio and cross-sectional aspect ratio on the ultimate strength and ductility of the composite columns. Experimental results indicate that the binding bars increase the confinement of the concrete core and delay local buckling of the tube. The results also show that R-CFT columns with binding bars have better ductility than those without binding bars. A model is proposed to predict the ultimate strength of the specimens. A comparison of the ultimate strengths between tests and design codes shows that the proposed model gives reasonable predictions of the ultimate strength of rectangular CFT stub columns with binding bars while the codes EC4 (1996), AIJ (1997) and GJB (2001) conservatively estimate the ultimate strength by 17.6%, 22.9% and 9.7% respectively.

[1]  J. Mander,et al.  Theoretical stress strain model for confined concrete , 1988 .

[2]  Brian Uy,et al.  Local and post-local buckling of concrete filled steel welded box columns , 1998 .

[3]  Keh-Chyuan Tsai,et al.  AXIAL LOAD BEHAVIOR OF STIFFENED CONCRETE-FILLED STEEL COLUMNS , 2002 .

[4]  Hanbin Ge,et al.  Cyclic Tests of Concrete-Filled Steel Box Columns , 1996 .

[5]  Dalin Liu,et al.  Axial load behaviour of high-strength rectangular concrete-filled steel tubular stub columns , 2005 .

[6]  Hanbin Ge,et al.  Strength analysis of concrete-filled thin-walled steel box columns , 1994 .

[7]  Toshiyuki Kitada,et al.  Ultimate strength and ductility of state-of-the-art concrete-filled steel bridge piers in Japan , 1998 .

[8]  Brian Uy,et al.  Strength of short concrete filled high strength steel box columns , 2001 .

[9]  Hiroyuki Nakahara,et al.  Behavior of centrally loaded concrete-filled steel-tube short columns , 2004 .

[10]  Richard W. Furlong.  Design of Steel-Encased Concrete Beam-Columns , 1968 .

[11]  Stephen P. Schneider,et al.  Axially Loaded Concrete-Filled Steel Tubes , 1998 .

[12]  Robert Park,et al.  Strength of Concrete Filled Steel Tubular Columns , 1969 .

[13]  Jian Cai,et al.  Axial load behavior of square CFT stub column with binding bars , 2006 .

[14]  Hanbin Ge,et al.  Strength of Concrete‐Filled Thin‐Walled Steel Box Columns: Experiment , 1992 .

[15]  Richard W. Furlong,et al.  Strength of Steel-Encased Concrete Beam Columns , 1967 .

[16]  Masahide Tomii,et al.  Experimental Studies on Concrete-Filled Steel Tubular Stub Columns under Concentric Loading , 1977 .