Abstract This paper firstly developed high performance sandwich composite beams with novel J-hooks and ultra-high performance concrete (UHPC), i.e., steel-UHPC-steel sandwich composite beams with J-hooks (SUSSBJs). Nine full-scale two-point loading tests were then performed on SUSSBJs to study their ultimate strength behaviour. The test results revealed that all SUSSBJs exhibited flexural failure even for SUSSSBJs with short shear span ratio of 2.41 and high spacing of J-hooks of 200 mm due to the high performance UHPC. The test results showed the SUSSBJs exhibited a four-stage working mechanism, which were initial elastic, elastic, nonlinear developing, and hardening stage. The test results also detailed reported and discussed the influences of key parameters on flexural behaviour of SUSSBJs. The flexural bending resistance of SUSSBJs was reduced for small shear span ratios; the spacing of J-hooks did not change the flexural failure mode, but reduces its ultimate strength as well as working mechanism; and all the strength and stiffness indexes increase linearly with the increasing thickness of faceplate. Finally, this paper developed analytical models on stiffness and strengths indexes of SUSSBJs, and the validations against nine test results proved their capabilities on predicting these indexes.

中文翻译：

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带 J 形钩连接件的钢-UHPC-钢夹层梁的弯曲行为

摘要 本文首次研制了新型J型钩和超高性能混凝土(UHPC)的高性能夹层组合梁，即钢-UHPC-钢J型钩夹层组合梁(SUSSBJs)。然后对 SUSSBJ 进行了九次全尺寸两点加载测试，以研究它们的极限强度行为。测试结果表明，由于高性能 UHPC，即使对于剪跨比为 2.41 的短剪跨比和 J 形钩间距为 200 毫米的 SUSSSBJ，所有 SUSSBJ 也表现出弯曲破坏。测试结果表明，SUSSBJs表现出四个阶段的工作机制，即初始弹性阶段、弹性阶段、非线性发展阶段和硬化阶段。测试结果还详细报道和讨论了关键参数对SUSSBJ弯曲行为的影响。对于小剪跨比，SUSSBJ 的抗弯弯曲能力降低；J形钩的间距没有改变弯曲破坏模式，但降低了其极限强度和工作机制；并且所有强度和刚度指标都随着面板厚度的增加而线性增加。最后，本文开发了 SUSSBJ 刚度和强度指标的分析模型，并通过 9 个测试结果的验证证明了它们对这些指标的预测能力。