Experimental study on K-joints of concrete-filled steel tubular truss structures

Abstract The failure modes of K-joints of Concrete Filled Steel Tubular (CFST) truss structures were investigated through laboratory tests. CFST K-joint specimens consisted of a tubular chord filled with concrete and two braces inclined at the same angle with respect to the chord. Their size was chosen of the same scale as that of joints of real tubular structures currently used in bridges. The results were compared with those obtained by testing K-joint specimens of Circular Hollow Section (CHS) truss structures with the same size. Contrary to CHS K-joints, where a chord face failure mode occurred, in CFST K-joints no failure mode with inward deformation of the chord section can occur. Hence, punching shear failure was shown to be the typical failure mode of CFST K-joints, if no brace failure mode occurred before. Resistance of CFST K-joints to punching shear was then compared with the resistance values calculated through the Eurocode 3 and the AWS code formulae on CHS K-joints. The values provided by the former formula were quite close to (although always lower than) the actual resistance to punching shear of CFST K-joints. Finally, the favourable effect on joint resistance due to additional studs welded to the interior surface of the chord tube of CFST K-joint was also investigated.

[1]  Bruno Briseghella,et al.  Effects of debonding on circular CFST stub columns , 2012 .

[2]  Bruno Briseghella,et al.  Resistance of Welded Joints of Concrete Filled Steel Tubular Truss Girders , 2012 .

[3]  Baochun Chen,et al.  Overview of Concrete Filled Steel Tube Arch Bridges in China , 2009 .

[4]  Jaap Wardenier,et al.  Evaluation of the recent IIW (2012) and ISO (2013) strength equations for axially loaded CHS K gap joints , 2014 .

[5]  Jaap Wardenier,et al.  Hollow section joints , 1982 .

[6]  Jeffrey A Paker,et al.  Hollow structural section connections and trusses : a design guide , 1997 .

[7]  Lin-Hai Han,et al.  Concrete-filled circular steel tubes subjected to local bearing force: Experiments , 2013 .

[8]  L. H. Lu.  The Static Strength of I-Beam to Rectangular Hollow Section Column Connections , 1997 .

[9]  Zhang Bo-yi.  Experimental research on ultimate bearing capacity of grouted-round-steel-tube N-joint , 2007 .

[10]  Lin-Hai Han,et al.  Concrete-filled circular steel tubes subjected to local bearing force: Finite element analysis , 2014 .

[11]  I. E. Tebbett,et al.  The Punching Shear Strength Of Tubular Joints Reinforced With a Grouted Pile , 1979 .

[12]  Chen Baochun.  Research on influence of web member on mechanical behavior of CFST truss girders , 2009 .

[13]  Lin-Hai Han,et al.  Tests on curved concrete filled steel tubular members subjected to axial compression , 2011 .

[14]  Q. Wu,et al.  Nonlinear seismic properties of the Second Saikai Bridge: A concrete filled tubular (CFT) arch bridge , 2006 .

[15]  Jaap Wardenier,et al.  Simulation of Ductile Fracture of Circular Hollow Section Joints Using the Gurson Model , 2005 .

[16]  Lin-Hai Han,et al.  Flexural behaviour of curved concrete filled steel tubular trusses , 2014 .

[17]  Ben Young,et al.  Tests of concrete-filled stainless steel tubular T-joints , 2008 .

[18]  K. Suzuki,et al.  Microstructural features and deformation-induced lattice defects in hot-extruded Bi2Te3 thermoelectric compound , 2009 .

[19]  Chanakya Arya,et al.  Eurocode 3: Design of steel structures , 2018, Design of Structural Elements.

[20]  Lin-Hai Han,et al.  Some Recent Developments of Concrete Filled Steel Tubular (CFST) Structures in China , 2010 .

[21]  Jeffrey A. Packer.  Concrete-Filled HSS Connections , 1995 .

[22]  Jaap Wardenier.  Design guide for circular hollow section (CHS) joints under predominantly static loading , 1991 .

[23]  Yue Yin,et al.  Ultimate load capacity and reinforcement of circular-hollow-section N-joint , 2010 .

[24]  X. Zhao,et al.  Hollow sections in structural applications , 2010 .

[25]  Y. Sakai,et al.  Experiments on concrete filled and reinforced tubular K-joints of truss girder , 2004 .