Influence of concrete type on the structural performance of timber-concrete composite T-beams using adhesively bonded perfobond connections: experimental and analytical evaluation

Abstract

Timber-concrete composite (TCC) systems are increasingly adopted in structural applications, placing greater emphasis on the performance of shear connection systems. In this study, the performance of a novel type of connector in TCC systems, the perfobond shear connector, is experimentally investigated in full-scale TCC T-beams in which two concrete types are considered, lightweight and normal weight concrete. The structural response is evaluated through force-deflection behaviour and failure modes. In all cases, connection failure precedes tensile bending failure of the timber member. Replacing normal weight concrete with lightweight concrete reduces self-weight, resulting in a slight decrease in bending stiffness and yield load due to reduced density. The experimental results are used to assess the applicability of the Gamma method, revealing deviations. An alternative approach proposed by Girhammar is therefore evaluated. A comprehensive comparison, including literature data, indicates that the Gamma method should be limited to connection spacings up to 4% of the span, while the Girhammar method provides a suitable alternative for larger spacings.