The applying of the high-strength steel bars to the ultra-high performance concrete (UHPC) structure can bring the advantages of the high strength of the steel bars and the UHPC into full play.To have an understanding of the influences of the prestressing degrees and steel bar ratios on the seismic behavior of the UHPC beams reinforced with the prestressing high-strength steel bars,3 prestressed and 1 non-prestressed UHPC beams were designed and cast and the low-cycle repeated load tests for the beams were made.The seismic failure modes,hysteretic curves,skeleton curves,ductility indices,rigidity degradation and the energy dissipation and deformation recovery capacity of the different beams were analyzed and the laws of the influences of the prestressing degrees and the conversed steel bar ratios on the seismic behavior of the beams were studied.The results indicate that the UHPC beams that are non-prestressed and that have the medium prestressing degrees have good seismic and ductility behavior while the beams that have the high prestressing degrees have good crack-resistant and deformation recovery capacity.The increase of the prestressing degrees can decrease the energy dissipation capacity of the beams and improve the deformation recovery capacity,but has little influence on the rigid degradation rates.The increase of the conversed steel bar ratios can retard the rigidity degradation rates of the beams and decrease the energy dissipation capacity,but has little influence on the deformation recovery capacity.%将高强钢筋用于超高性能混凝土(UHPC),可充分发挥两者的高强性能.为了解预应力度和配筋率对预应力高强钢筋UHPC梁抗震性能的影响,设计制作了3根预应力和1根非预应力UHPC梁,进行低周反复荷载试验,分析各梁的抗震破坏形态、滞回曲线、骨架曲线、延性指标、刚度退化、耗能能力和变形恢复能力,探讨预应力度和换算配筋率对梁抗震性能的影响规律.结果表明:非预应力和中等预应力度UHPC梁具有良好的抗震性能和延性性能,高预应力度UH-PC梁具有较好的抗裂能力和变形恢复能力;提高预应力度会降低梁的耗能能力,改善变形恢复能力,但对刚度退化速率影响不大;提高换算配筋率可减缓刚度退化速率,降低梁的耗能能力,但对变形恢复能力影响不大.
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