Ultra-high-performance fibre-reinforced concrete (UHPFRC) has been widely adopted in the strengthening of reinforced concrete (RC) beams and slabs due to its excellent mechanical properties and durability. Although many studies have been conducted on the mechanical behaviours of RC structures reinforced by UHPFRC, the mechanical behaviours of UHPFRC-reinforced RC structures in a combined force state of bending and axial compression remain unknown. In this study, an eccentric compression short RC column, which was strengthened by a UHPFRC layer on the tension/compression side, was studied based on experiments and numerical simulations. Some key performance attributes of the short columns including load carrying capacity, stiffness, ductility, strain, cracking, and lateral deflection were investigated. In addition, finite element (FE) models were established to determine the influence of the reinforcement parameters including the reinforcement ratio and the thickness of the UHPFRC layer as well as the reinforcement location. The results showed that the UHPFRC layer could significantly increase the load carrying capacity and the stiffness while reducing the ductility of the short RC columns. In addition, the UHPFRC layer could delay the formation of cracks and control their development. The results also showed that the RC columns bonded well with the UHPFRC layers. No bond failure but partial bond slip occurred at the interface. Furthermore, the unreinforced UHPFRC layer could still effectively promote the load carrying capacity of the short RC columns, either reinforced on the tension or compression side. The improvement rate obviously increased with increasing thickness of the unreinforced UHPFRC layer.

超高性能纤维增强混凝土（UHPFRC）由于其优异的机械性能和耐用性而被广泛用于增强钢筋混凝土（RC）梁和楼板。尽管已经对UHPFRC增强的RC结构的力学性能进行了许多研究，但仍不清楚UHPFRC增强的RC结构在弯曲力和轴向压缩力共同作用下的力学性能。在这项研究中，基于实验和数值模拟，研究了偏心压缩短RC柱，该柱由拉伸/压缩侧的UHPFRC层加固。研究了短柱的一些关键性能属性，包括承载能力，刚度，延性，应变，破裂和横向挠度。此外，建立有限元（FE）模型来确定包括加筋率和UHPFRC层厚度以及加筋位置在内的加筋参数的影响。结果表明，UHPFRC层可以显着提高承载能力和刚度，同时降低短RC柱的延展性。另外，UHPFRC层可以延迟裂纹的形成并控制裂纹的发展。结果还表明，RC柱与UHPFRC层粘结良好。没有粘结失败，但在界面处发生了部分粘结滑移。此外，未增强的UHPFRC层仍可以有效地提高短RC柱的承载能力，无论是在受压侧还是在压缩侧进行增强。