TY - JOUR

T1 - Experimental and numerical investigations of the composite behaviour in concrete-filled tubular columns with massive steel core at high temperatures

AU - Schaumann, Peter

AU - Kleibömer, Inka

N1 - Funding information: The presented work is part of the European RFCS-research project FRISCC (“Fire resistance of innovative and slender concrete filled tubular composite columns”) and was kindly funded by the European Commission (Grant No. RFSR-CT-2012-00025).

PY - 2018/6/11

Y1 - 2018/6/11

N2 - Purpose: This paper deals with experimental and numerical investigations of the composite behaviour within concrete-filled tubular columns with embedded massive steel core (CFTES columns). As the inner profile provides the main load-bearing capacity, the load introduction and transfer is of particular interest for the structural detailing of CFTES columns. Currently, no specific design regulations are available – neither for room temperature nor fire design. The presented investigations provide a basis for design recommendations and numerical approaches on reliable shear stresses. Design/methodology/approach: Three series of push-out tests at room temperature and high temperatures are analysed in terms of ultimate shear strength, bond strength and shear strength-displacement-curve shape. The test parameters involve the steel core diameter and concrete cover, applying normal strength steel and concrete. Furthermore, a three-dimensional finite element model of the push-out tests is set up in Abaqus. The model implies temperature-dependent contact properties derived from the experimental tests using the cohesive behaviour method. Findings: The test data reveal a distinctive reduction in both ultimate shear and bond strength for high temperatures. For high temperatures, the thermal expansion coefficients dominate the composite behaviour. Using the 3D numerical model and applying a temperature-dependent joint stiffness, maximum shear stress criterion and damage evolution, the observed composite behaviour can be described in a realistic manner. Originality/value: The presented experimental investigations are unique, both concerning the investigated column type and performing push-out tests at high temperatures. For the first time, a temperature-dependent reduction of capable shear stresses is identified, which is crucial for the design of structural components.

AB - Purpose: This paper deals with experimental and numerical investigations of the composite behaviour within concrete-filled tubular columns with embedded massive steel core (CFTES columns). As the inner profile provides the main load-bearing capacity, the load introduction and transfer is of particular interest for the structural detailing of CFTES columns. Currently, no specific design regulations are available – neither for room temperature nor fire design. The presented investigations provide a basis for design recommendations and numerical approaches on reliable shear stresses. Design/methodology/approach: Three series of push-out tests at room temperature and high temperatures are analysed in terms of ultimate shear strength, bond strength and shear strength-displacement-curve shape. The test parameters involve the steel core diameter and concrete cover, applying normal strength steel and concrete. Furthermore, a three-dimensional finite element model of the push-out tests is set up in Abaqus. The model implies temperature-dependent contact properties derived from the experimental tests using the cohesive behaviour method. Findings: The test data reveal a distinctive reduction in both ultimate shear and bond strength for high temperatures. For high temperatures, the thermal expansion coefficients dominate the composite behaviour. Using the 3D numerical model and applying a temperature-dependent joint stiffness, maximum shear stress criterion and damage evolution, the observed composite behaviour can be described in a realistic manner. Originality/value: The presented experimental investigations are unique, both concerning the investigated column type and performing push-out tests at high temperatures. For the first time, a temperature-dependent reduction of capable shear stresses is identified, which is crucial for the design of structural components.

KW - Composite behaviour

KW - Concrete-filled tubular column

KW - Experimental test

KW - High temperature

KW - Numerical simulation

KW - Steel core

UR - http://www.scopus.com/inward/record.url?scp=85033567696&partnerID=8YFLogxK

U2 - 10.1108/JSFE-01-2017-0010

DO - 10.1108/JSFE-01-2017-0010

M3 - Article

AN - SCOPUS:85033567696

VL - 9

SP - 147

EP - 160

JO - Journal of Structural Fire Engineering

JF - Journal of Structural Fire Engineering

SN - 2040-2317

IS - 2

ER -