Study on Deflection and Deformation Performance of UHPC-Steel Truss Web Composite Beams

本文针对超高性能混凝土(UHPC)与钢桁腹组合梁的受力性能展开研究。基于经典梁理论，建立了考虑弯曲变形与剪切变形耦合作用的挠度计算模型，并对钢桁腹杆进行等效换算处理，将离散腹杆转化为连续钢腹板以便于剪切变形的分析，用于进行UHPC-钢桁腹组合梁在集中荷载作用下挠度的计算。通过有限元分析以及静力试验，我们对UHPC-钢桁腹组合梁在荷载影响下的挠度分布、应变特性和破坏模式进行了全面和系统的研究。试验结果表明，理论计算值与有限元及试验结果较为吻合，其中理论模型略显保守，有助于在工程设计中提供额外安全度。同时，对比分析揭示了不同部位(跨中与支座附近)弯曲与剪切变形对挠度贡献的区域性差异，为结构优化设计提供了理论依据。This paper investigates the mechanical performance of composite beams made of ultra-high performance concrete (UHPC) and steel truss webs. Based on classical beam theory, a deflection calculation model considering the coupled effects of bending and shear deformations is established. The steel truss web members were equivalently converted into a continuous steel web plate to facilitate the analysis of shear deformation. This model is used to calculate the deflection of UHPC-steel truss web composite beams under concentrated loading. Through finite element analysis and static tests, we conducted a comprehensive and systematic study on the deflection distribution, strain characteristics, and failure modes of UHPC-steel truss web composite beams under load. The test results show that the theoretical calculation values are in good agreement with the finite element and experimental results, with the theoretical model being slightly conservative, which helps provide an additional safety margin in engineering design. Moreover, comparative analysis revealed regional differences in the contributions of bending and shear deformation to deflection at different locations (midspan and near supports), providing a theoretical basis for structural optimization design.