Investigation on Shear Performance of Concrete T-Beam Bridge Strengthened Using UHPC

This investigation examines the shear performance of concrete T-beams reinforced with thin layers of ultra-high performance concrete (UHPC) through an approach that integrates experimental evaluation, numerical simulation, and practical project verification. The research is based on a real bridge, and in accordance with the similarity principle, three reduced-scale T-beams with varying UHPC thicknesses were fabricated and tested to examine their failure modes and shear behaviors. A finite element model was created to enhance understanding of how UHPC reinforces these structures, while also considering the effects of material strength and arrangement. In addition to the laboratory tests, the actual bridge was analyzed to assess the effectiveness of the proposed strengthening technique. Results indicated that concrete T-beams strengthened with 30 mm-thick layers of UHPC had significant improvements, including a 491% increase in shear stiffness, a 23.15% rise in ultimate resistance, and a 155% enhancement in deformability compared to unreinforced T-beams. Furthermore, these improvements continued to increase with the application of thicker UHPC layers. Using 120 MPa-grade UHPC with a thickness of 50 mm and an A-type arrangement ensured that the dynamic and static performance of the T-beam bridge met established code requirements. This research highlights the potential of UHPC thin layers in effectively reinforcing concrete beams for enhanced shear performance.