ANALYTICAL MODEL FOR THE PREDICTION OF THE ELASTIC RESPONSE OF CURVED T-STUBS

Andrej Mudrov,Jean-Pierre Jaspart,Adrien Corman,Antanas Šapalas

doi:10.3846/jcem.2021.15206

Abstract

Composite steel-concrete columns utilise the advantages of both materials, by combining high strength and ductility of steel with the compressive strength of the concrete. But the wide adaptation of composite structures is limited, mainly because of the lack of cheap and easy to construct connections, as many of which require costly and timeconsuming on-site welding, when circular concrete filled steel tubes (CFST) are adopted. New connections, like those incorporating the use of blind bolts and curved end-plates, may represent a valuable alternative. Such joints can be adapted to circular CFST to eliminate on-site welding, but they require the creation of new curved T-stub components. This paper proposes an analytical model for the evaluation of bolt forces in the curved T-stubs within the elastic range. The model is then validated against experimental results of joints between circular CFST columns and steel beams, with both preloaded and snug tightened bolts. Analytical model shows good agreement with experimental data, but needs further development to take into account the prying forces.

Highlights

Steel-concrete composite structures offer high strength, stiffness and superior ductility
The wide adaptation of composite structures is limited, mainly because of the lack of cheap and easy to construct connections, as many of which require costly and timeconsuming on-site welding, when circular concrete filled steel tubes (CFST) are adopted. Like those incorporating the use of blind bolts and curved end-plates, may represent a valuable alternative. Such joints can be adapted to circular CFST to eliminate on-site welding, but they require the creation of new curved T-stub components
This paper proposes an analytical model for the evaluation of bolt forces in the curved T-stubs within the elastic range

Summary

Introduction

Steel-concrete composite structures offer high strength, stiffness and superior ductility. They examined works of Alostaz and Schneider (1996), in which weldable deformed bars were used to redistribute flange forces into the concrete core, and come up with the idea of a curved flange plated joint This joint was bolted to the circular column by means of blind bolts, that allowed to eliminate on-site welding. Oktavianus et al (2014) showed that, by increasing the bolt inclination angle α (Figure 1c), stiffness and resistance of the curved T-stub decrease It became clear through these works that the T-stub approach recommended in Eurocode 3 Part 1-8 (European Committee for Standardization, 2005) for flat end-plate could not be directly extended to curved T-stubs, but that blind bolting could be more accommodated. The horizontal thrust force H (Figure 2a) is here equal

Behaviour of curved T-stub in tension

Simplification

Experimental evaluation

Verification of design equations

Findings

Conclusions