Experimental investigations of dry-dry timber-concrete composite notched connections designed for disassembly

Abstract

Timber-Concrete Composite (TCC) decks offer an efficient, and environmentally friendly alternative to conventional concrete slabs. Traditionally the concrete is cast directly onto the timber with a permanent connection arrangement that does not allow non-destructive disassembly at end-of-service-life. This will prevent the reuse of the materials and ultimately decrease the extent of the environmental benefit. This paper presents a deconstructable dry-dry notched connection made from fully prefabricated timber and concrete elements. The concept was investigated through 30 experimental pure-shear push-off tests, where various design parameters, such as prestressing degree, fastener placement, and notch length, were varied. The experimental results indicate that the new connection exhibits the same stiffness characteristics as a traditional wet-dry notched connection. Five different failure modes were observed in the series, and experimental measurements such as Digital Image Correlation and fastener force measurement provided insight into the connection behavior during failure. Two rigid-plastic upper bound solutions were established to estimate the load-carrying capacity for two of the observed concrete failures, and a satisfactory agreement with the test results was obtained. In conclusion, the experimental results indicated that dry-dry notched connections are feasible for achieving a more environmentally friendly TCC structure.