Short- and long-term performance of the “Tecnaria” stud connector for timber-concrete composite beams

The paper presents the results of some experimental tests performed on the shear stud connection system for timber-concrete composite beams manufactured by the Tecnaria Ltd. Some push-out specimens constructed using both normal weight (NW) and light weight (LW) concrete were subjected to collapse and long-term creep tests. During the collapse test, the connector exhibited significant strength and stiffness. In the creep test performed in constant environmental conditions, delayed (creep) deformations took place mainly during the first days after loading. The next part of the creep test, conducted under cycles of environmental relative humidity, was characterized by an increase in delayed deformations (the so-called mechano-sorptive effect) due to the hygroscopic behaviour of timber around the connector. The amount of delayed deformation depended upon the cycle duration and was negligible for short period (less than one week) cycles. The use of LW concrete instead of NW concrete was found not to significantly affect the performance of the connection system neither in the long-term, nor in the collapse tests.