Abstract Adopting UHPC in practical construction is very expensive due to the high steel fibre content (>2.5 vol%) and passive flexure reinforcement. Aiming at balancing the performance and cost, two UHPC column designs (2000 × 168 × 168 mm) are proposed in the present study. Hollow-core components and steel wire mesh reinforced components were cast with UHPC that contained 1.5 vol% steel fibre, and the impact resistance of both structural types was studied. The test specimens included two hollow-core UHPC columns with square and circular hollow shapes, and two steel wire mesh reinforced UHPC columns with 6 and 10 layers wire mesh reinforcement. The impact scenario was modelled with a 411 kg drop hammer falling freely from 1.25 m height to the mid-span of the test specimen. The results demonstrated that all UHPC specimens remained a flexural response with minimal damage. The developed numerical model captured the impact force, structural deformation and damage with reasonable accuracy. With the validated model, the energy evolution, dynamic shear and moment distribution, residual axial capacity and damage level of post-impact columns were evaluated. The effects of hollow section shape and ratio, axial load level, and longitudinal reinforcement ratio for hollow-core UHPC columns and the effects of layers of steel wire mesh for steel wire mesh reinforced UHPC columns were investigated. Compared with other hollow-core UHPC columns under the impact velocities between 4.95 m/s – 6.64 m/s, UHPC columns with a circular hollow section and 15% hollow ratio was the most effective in balancing the cost and impact resistance. For steel wire mesh reinforced UHPC columns, the column with steel wire mesh strengthening in the whole section had better impact resistance than its counterpart that only had wire mesh reinforcement in the tensile zone.

中文翻译：

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空心钢丝网增强超高性能混凝土柱在横向冲击荷载作用下的性能

摘要 由于高钢纤维含量（> 2.5 vol%）和被动弯曲增强，在实际施工中采用 UHPC 非常昂贵。为了平衡性能和成本，本研究中提出了两种 UHPC 色谱柱设计（2000 × 168 × 168 mm）。空心构件和钢丝网增强构件采用含有 1.5 vol% 钢纤维的 UHPC 铸造，并研究了两种结构类型的抗冲击性。试验样品包括两根方形和圆形空心UHPC柱，以及两根6层和10层钢丝网增强的钢丝网增强UHPC柱。冲击场景是用 411 kg 落锤从 1.25 m 高度自由落下到试样的跨度中点来建模的。结果表明，所有 UHPC 试样均保持弯曲响应，且损伤最小。开发的数值模型以合理的精度捕获了冲击力、结构变形和损坏。使用经过验证的模型，评估了冲击后柱的能量演化、动态剪力和弯矩分布、残余轴向承载力和损坏程度。研究了空心截面形状和比例、轴向荷载水平和纵向配筋率对空心UHPC柱的影响以及钢丝网增强UHPC柱的钢丝网层数的影响。在4.95 m/s – 6.64 m/s的冲击速度下，与其他空心UHPC柱相比，圆形中空截面和15%中空比的UHPC柱在平衡成本和抗冲击性方面最为有效。