Bond strength, failure criteria and calculation methods for adhesively bonded timber–concrete composites

The bond strength of adhesively bonded timber–concrete composites (ATCC) with prefabricated concrete elements is usually described using the shear strength of the timber. This approach, however, often fails to consider the actual failure modes of the bondline and also the interaction between shear stresses and stresses perpendicular to the bondline has not yet been comprehensively understood. To address this limitation, a reliable calculation method is required, where stress determination, failure criterion, and stress analysis are clearly defined to accurately predict the bond failure of ATCC specimens. In this study, three linear-elastic calculation methods and one non-linear calculation method are presented along with corresponding failure criteria and strength parameters. Regarding validation, the predicted failure load is compared to experimental results from 186 ATCC bond specimens to assess the method’s suitability. Based on the findings, appropriate calculation methods for a reliable prediction of the bond strength are recommended.