Development of an innovative type of shear connector dedicated to fully embedded steel-concrete composite columns – experimental and numerical investigations.

Abstract

A shear connection in steel-concrete composite columns is established in the normal case with headed shear studs. However, this type of connector was developed for composite beams and in terms of composite columns, a wide range for an optimisation still can be identified due to the different geometries of steel profiles, concrete and reinforcement. The presented paper shows investigations on a new type of shear connector with a direct application to composite columns and with a potential for a fully automatic fabrication process. The proposed new type of shear connection is made out of reinforcement bars welded to the external surfaces of the steel profile’s flanges. The experimental campaign consisted of 12 composite push-out tests with a column section geometry. The analysed specimens included centrally embedded HEB120 steel profiles into 340x1000x450mm concrete blocks. All the tests have been categorized into 4 groups. One group per connector was defined (including group without mechanical connector). Each group had 3 identical specimens. Surface treatment conditions, reinforcement arrangement, used materials and test layout were the same in all executed tests. The acquired results showed a good performance of the proposed solutions and allowed to identify the different load-bearing behaviour. After the test execution, the specimens were opened and the failure pattern have been investigated. The testing campaign was supported by numerical simulations performed with the finite element software code Abaqus®. In the developed models, a new approach to simulate the steel-concrete bond was implemented.