Confinement effect of stiffened and unstiffened concrete-filled stainless steel tubular stub columns

This paper presents a comparative study between stiffened and unstiffened concrete-filled stainless steel hollow tubular stub columns using the austenitic stainless steel grade EN 1.4301 (304). Finite element analysis of concrete-filled stainless steel unstiffened tubular stub columns is constructed herein based on the confined concrete model recently available in the literature. It is then compared with the experimental results of concrete-filled stainless steel stiffened tubular stub columns. The stiffened stainless steel tubular sections were fabricated by welding four lipped angles or two lipped channels at the lips. The longitudinal stiffener of the column plate was formed to avoid shrinkage of the concrete and to act as a continuous connector between the concrete core and the stainless steel tube. The behavior of the columns was investigated using two different nominal concrete cubic strengths of 30 and 60 MPa. The overall depth-to-width ratios (aspect ratio) varied from 1.0 to 1.8. The depth-to-plate thickness ratio of the tube sections varied from 60 to 90. The stiffened and unstiffened concrete-filled stainless steel tube specimens were subjected to uniform axial compression over the concrete and stainless steel tube to force the entire section to undergo the same deformations by blocking action. The ABAQUS 6.6 program, as a finite element package, is used in the current work. The results of the comparative study showed that the stainless steel tubes in stiffened concrete-filled columns offered a high average of increase in the confinement of the concrete core than that of the unstiffened concrete-filled columns.

[1]  Ulf Wickström,et al.  Comments on calculation of temperature in fire-exposed bare steel structures in prEN 1993-1-2: Eurocode 3—design of steel structures—Part 1–2: general rules—structural fire design , 2005 .

[2]  Ehab Ellobody,et al.  Nonlinear behavior of concrete-filled stainless steel stiffened slender tube columns , 2007 .

[3]  L. P. Sanez,et al.  DISCUSSION OF EQUATION FOR THE STRESS - STRAIN CURVE OF CONCRETE’ BY DESAYI AND KRISHNAN , 1964 .

[4]  Hsuan-Teh Hu,et al.  NONLINEAR ANALYSIS OF AXIALLY LOADED CONCRETE-FILLED TUBE COLUMNS WITH CONFINEMENT EFFECT , 2003 .

[5]  Mostafa Fahmi Hassanein,et al.  Experimental investigation on concrete-filled stainless steel stiffened tubular stub columns , 2009 .

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

[7]  Leroy Gardner,et al.  A new approach to structural stainless steel design , 2002 .

[8]  Mostafa Fahmi Hassanein,et al.  A comparative experimental study between stiffened and unstiffened stainless steel hollow tubular stub columns , 2009 .

[9]  Kim J.R. Rasmussen,et al.  Numerical modelling of stainless steel plates in compression , 2003 .

[10]  L. P. Saenz.  Discussion of Equation for the Stress-strain Curve of Concrete by Desayi and Krishman , 1964 .

[11]  William C. Schnobrich,et al.  Constitutive Modeling of Concrete by Using Nonassociated Plasticity , 1989 .

[12]  Mathias Johansson,et al.  Composite Action and Confinement Effects in Tubular Steel-Concrete Columns , 2002 .

[13]  K. F. Chung,et al.  Composite column design to Eurocode 4 : based on DD ENV 1994-1-1: 1994 Eurocode 4: design of composite steel and concrete structures: part 1.1: general rules and rules for buildings , 1994 .

[14]  Ben Young,et al.  Experimental investigation of concrete-filled cold-formed high strength stainless steel tube columns , 2006 .

[15]  Leroy Gardner,et al.  The use of stainless steel in structures , 2005 .

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

[17]  E. Mirambell,et al.  On the calculation of deflections in structural stainless steel beams: an experimental and numerical investigation , 2000 .

[18]  Ehab Ellobody.  Buckling analysis of high strength stainless steel stiffened and unstiffened slender hollow section columns , 2007 .