Advanced Steel Construction

Vol. 14, No. 2, pp. 274-290 (2018)


COMPOSITE EFFECT OF STUB SQUARE STEEL TUBED

COLUMNS UNDER AXIAL COMPRESSION

 

X. H. Zhou1, D. Gan 1,2*, J. P. Liu1 and Y. F. Chen3

1Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400045, China

2School of Civil Engineering, Chang’an University, Xi’an 710061, China

3 Department of Civil Engineering, The Pennsylvania State University, Middletown, PA 17057, USA

*(Corresponding author: E-mail:This email address is being protected from spambots. You need JavaScript enabled to view it.)

Received: 28 January 2016; Revised: 16 December 2016; Accepted: 27 December 2017

  

DOI:10.18057/IJASC.2018.14.2.8

 

ABSTRACT:

The in-filled concrete of square tube confined concrete columns (tubed columns for short) is non-uniformly confined and the effectiveness of its confinement is reduced, leading to a complex composite effect. This paper discusses key parameters, including friction, width-to-thickness ratio and chamfered corner radius of steel tubes, which would affect the confinement of square tubes on in-filled concrete. Eighteen specimens with large width-to-thickness ratio and six RC counterparts were tested under axial compression. Four main system parameters were considered in the tests: 1) width-to-thickness ratio (60-160); 2) types of steel tubes (galvanized and ordinary); 3) interface between tube and concrete (reduced friction and not); and 4) with and without reinforcement cage. It was found that the square tubed RC and plain RC columns were characterized by the shear failure mode, but the ductility performance of the tubed columns was much better than the RC specimens. The axial load-carrying capacities of the specimens with smaller friction were slightly lower than those with larger friction. A finite element analysis (FEA) model was developed to analyze the influence of friction and corner radius on of square tubed columns. An effective section confining model considering effective utilization index of square steel tubes was developed to predict the axial load resistances. The results are satisfactory when comparing the predictions to the experimental and nonlinear finite element analysis results.

 

Keywords:

Square steel tubed column, concrete-filled tube column, composite effect, friction coefficient, effective utilization index, axial load-carrying capacities

 

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