【摘要】 为解决小箱梁承载力不达标问题，本研究采取超高性能混凝土（UHPC）对钢筋混凝土小箱梁实施特定部位的加固方案，并将加固部位设定为研究变量。通过四点弯曲试验和抗剪切试验，探究加固前后的梁体抗弯特性，得出跨中荷载与位移关系曲线，并在此基础上深入剖析UHPC加固层对箱梁承载力、抗弯性能以及抗剪性能的影响。研究结果表明：采用强度等级为C150的UHPC对顶部、腹部和底部进行加固后，箱梁的极限抗弯承载能力分别提升了38.76%、76.09%和90.75%；箱梁在加固后的抗剪承载能力和抵抗形变的能力均得到明显增强；加固处理后，成功地限制了梁体结构损伤的恶化趋势，为箱梁带来了更高的安全保障水平。在3种加固方式中，采用底部加固效果最佳，腹部加固效果相比前者差距较小，而顶部加固效果最差。更多还原

【Abstract】 To address the issue of substandard bearing capacity of small box girders, this study adopts a reinforcement plan with ultra-high performance concrete(UHPC) for specific parts of reinforced concrete small box girders, and sets the reinforcement parts as research variables. Through four point bending test and shear test, the bending characteristics of the beam before and after reinforcement are explored, and the relationship curve between mid span load and displacement is obtained. Based on this, the effects of UHPC reinforcement layer on the bearing capacity, bending performance, and shear performance of the box beam are analyzed in depth. The research results show that using UHPC concrete with a strength grade of C150 to reinforce the top, abdomen, and bottom of the box girder increases the ultimate bending bearing capacity by 38.76 %, 76.09 %, and 90.75 %, respectively. After reinforcement treatment, the shear bearing capacity and deformation resistance of the box girder is significantly enhanced; After reinforcement, the deterioration trend of damage to the beam structure is successfully limited, thereby bringing a higher level of safety assurance to the box girder. Among the three reinforcement methods, the bottom reinforcement has the best effect, while the abdominal reinforcement has only a small difference compared to the former. On the other hand, the top reinforcement has a worst effect.更多还原