Experimental Study on Mechanical Behavior of Shear Connectors of Square Concrete Filled Steel Tube

In order to quantitatively evaluate the shear-bearing capacity of shear connectors of square concrete filled steel tube (CFST), push-out tests on 14 square CFSTs with shear connectors have been carried out. Among the 14 CFSTs, there are 13 specimens with steel plate connectors and one specimen with steel bar connectors. The following factors are investigated to figure out their influences on the performance of CFSTs, which are the width to thickness ratio of steel tube, thickness of steel plate, length of steel plate, strength of concrete, welding condition of steel plate, number of steel plate layer and interlayer spacing. The test results show that the ultimate bearing capacity and the elastic stiffness increase with decreasing width to thickness ratio of the steel tube, and increasing thickness and length of the steel plate. With increasing concrete strength, the ultimate bearing capacity also increases. However, the welding condition has no effect on the ultimate bearing capacity. The ultimate bearing capacity of the CFST with double-layer steel plate is greater than that with single-layer steel plate. The ultimate bearing capacity of steel bar type shear connector is 87% greater than that of the steel plate type shear connector, and the steel bar specimen shows good ductility. A formula for calculating the shear-bearing capacity of shear connectors has been developed, and the calculated shear-bearing capacities are in good agreement with the test data.

[1]  Chang-Su Shim,et al.  Static behavior of large stud shear connectors , 2004 .

[2]  Sung-Pil Chang,et al.  Static and fatigue behavior of large stud shear connectors for steel–concrete composite bridges , 2005 .

[3]  M. H. Lai,et al.  Confinement effect of ring-confined concrete-filled-steel-tube columns under uni-axial load , 2014 .

[4]  Chang Xu,et al.  Push-out test of pre-stressing concrete filled circular steel tube columns by means of expansive cement , 2009 .

[5]  Weichen Xue,et al.  Static Behavior and Theoretical Model of Stud Shear Connectors , 2008 .

[6]  Dennis Lam,et al.  Axial capacity of circular concrete-filled tube columns , 2004 .

[7]  Lin-Hai Han,et al.  The Influence of Concrete Compaction on the Strength of Concrete Filled Steel Tubes , 2000 .

[8]  L. An,et al.  Push-out tests on studs in high strength and normal strength concrete , 1996 .

[9]  I Patnaikuni,et al.  Incremental collapse threshold for pushout resistance of circular concrete filled steel tubular columns , 2010 .

[10]  Lin-Hai Han,et al.  Tests on Stub Columns of Concrete-filled RHS Sections , 2002 .

[11]  R. P. Johnson,et al.  Design of composite steel and concrete structures , 1993 .

[12]  H Shakir-Khalil,et al.  PUSHOUT STRENGTH OF CONCRETE-FILLED STEEL HOLLOW SECTION TUBES , 1993 .

[13]  Charles W. Roeder,et al.  Composite Action in Concrete Filled Tubes , 1999 .

[14]  Brian Uy,et al.  Bond behavior in concrete-filled steel tubes , 2016 .

[15]  Nobuyuki Nakamura,et al.  EVALUATION OF BEARING STRENGTH OF BACKING RINGS FOR CONCRETE FILLED TUBE , 1997 .