Static load anchoring performance of composite anchorage with 3D printing homologous materials used for CFRP bars

To achieve efficient anchoring of carbon fiber reinforced polymer (CFRP) bars and quantify the influence of key parameters on the anchoring efficiency of the homologous materials anchorages, as well as to promote the application of 3D printing CFRP technology in bridge engineering, a systematic exploration was conducted from both experimental and simulation perspectives. Firstly, a new type of parallel composite anchorage made of homologous materials for CFRP bars was designed and fabricated using 3D printing CFRP technology. Secondly, key parameters including anchorage cup length, thickness of bonding medium, number of wedges, pre-tightening ratio of wedges, and shape of grouting cup were selected for short-term static load tensile tests to investigate the influence of different parameters on the static load anchoring performance. Furthermore, a simulation model capable of accurately characterizing the performance of the 3D printing parallel composite anchorage was constructed based on the fundamental mechanical parameters of 3D printing CFRP. Results show that there are three failure modes of the anchorage system: tensile failure of bars, shear failure, and slip failure. The anchorage efficiency improves with the increase of anchorage cup length, pre-tightening ratio of wedges, and number of wedges. Specifically, the conical bonding medium exhibits higher anchoring efficiency compared to the cylindrical one. Under the combined conditions of a conical bonding medium, 100% pre-tightening ratio of wedges, anchorage cup length of 120 mm, and 3 wedges, the anchoring efficiency reaches 103.33%, which meets the standard requirements. This optimal configuration maintains structural integrity without failure. As the load increases, stress redistribution occurs at the CFRP bar-bonding medium interface. Additionally, the errors between experimental data and simulation results are controlled within 10%, and the trends are consistent, indicating that the constructed simulation model has a good strong predictive capability. In summary, the effectiveness of 3D printing homologous materials anchorage for the single CFRP bar is verified, which provides a theoretical basis and technical support for advancing the use of homologous materials in anchorages for CFRP bars.