Experimental and numerical investigations of the composite behaviour in concrete-filled tubular columns with massive steel core at high temperatures. (31st August 2017)

• Record Type: Journal Article
• Authors: Schaumann, Peter; Kleibömer, Inka
• Is Part Of: Journal of structural fire engineering. Volume 9:Number 2(2018)
• Page Start: 147
• Page End: 160
• Publication Date: 2017-08-31
• Subjects: High temperature -- Numerical simulation -- Experimental test -- Composite behaviour -- Concrete-filled tubular column -- Steel core; Fire protection engineering -- Periodicals; 628.92205
• DOI: 10.1108/JSFE-01-2017-0010
• Languages: English
• ISSNs: 2040-2317

Abstract

Abstract : 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.