Numerical Evaluation of the Influence of Using Carbon-Fiber-Reinforced Polymer Rebars as Shear Connectors for Cross-Laminated Timber-Concrete Panels

Carbon fiber-reinforced polymer (CFRP) sheets have been used to reinforce cross-laminated timber (CLT)-concrete systems in recent years. The existing studies have indicated that the use of CFRP rebars as shear connectors in CLT-concrete panels can improve the structural performance of these elements. However, the application and understanding of CFRP rebars as shear connectors still need to be improved, since comprehensive studies on the subject are not available. Therefore, this research aimed to evaluate the structural performance of CLT-concrete panels with CFRP rebars as shear connectors through finite element (FE) numerical simulation. A parametric study was conducted, varying the connector material, the number of CLT layers, the connector insertion angle, and the connector embedment length. According to the results, panels with CFRP connectors showed a higher maximum load, bending strength, and maximum bending moment than panels with steel connectors. The regression models revealed that the parameters analyzed explained between 80.2% and 99.9% of the variability in the mechanical properties under investigation. The high explanatory power (R2) of some regression models in this study underscores the robustness of the models. The number of CLT layers and the connector material were the most significant parameters for the panels' maximum load, displacement at the maximum load, ductility, bending strength, and maximum bending moment. The number of CLT layers and the connector insertion angle were the most significant parameters for the panels' effective bending stiffness. This research highlights the importance of studies on CLT-concrete composites and the need to develop equations to estimate their behavior accurately. Moreover, numerical simulations have proven very valuable, providing results comparable to laboratory results.