铁道建筑

为研究超高性能混凝土(ultra-high performance concrete， UHPC)薄板模壳在侧压力及局部集中荷载作用下其抗弯承载力与变形性能，设计了相关静力荷载试验；通过改变板平面尺寸、板厚及配筋率，设计并完成8块UHPC双向薄板静力加载试验，分析试件的荷载—挠度曲线、裂缝发展特征及破坏模式，揭示主要参数对抗弯性能的影响规律。理论研究方面，结合截面应变分布特征，构建等效截面受力模型。引入塑性铰线理论，提出集中荷载作用下UHPC双向薄板抗弯承载力的计算方法；研究结果表明，各试件均以弯曲破坏为主，未配筋薄板在开裂后裂缝迅速扩展并贯通，破坏较为集中；配置构造钢筋后，裂缝发展得到有效抑制，峰值荷载后仍保持一定承载能力，构件变形性能明显改善。板厚对抗弯承载力影响最为显著，在相同配筋条件下，板厚由40mm增加至55mm时，900mm边长试件峰值承载力提高约44%，1250mm边长试件提高约31%；基于等效截面模型与塑性铰线理论建立的计算方法能够较好预测UHPC双向薄板在集中荷载作用下的极限抗弯承载力，可为UHPC薄板模壳结构设计提供参考。

To investigate the flexural bearing capacity and deformation behavior of ultra-high performance concrete (UHPC) thin plate formwork under lateral pressure and localized concentrated loads， relevant static load tests were designed. By varying the slab's planar dimensions， thickness， and reinforcement ratio， eight UHPC bidirectional thin slabs were designed and subjected to static loading tests. The load-deflection curves， crack propagation characteristics， and failure modes of the specimens were analyzed to elucidate the influence of key parameters on flexural performance. In terms of theoretical research， an equivalent cross-sectional force model is constructed in combination with the characteristics of the cross-sectional strain distribution. By introducing the theory of plastic hinge lines， a calculation method for the flexural bearing capacity of UHPC bidirectional thin slabs under concentrated loads was proposed. The research findings reveal that all specimens primarily experienced flexural failure， with unreinforced thin slabs exhibiting rapid crack propagation and penetration upon cracking， leading to concentrated failure. The incorporation of structural reinforcement effectively suppressed crack development， enabling the slabs to maintain a certain load-bearing capacity beyond the peak load and significantly improving their deformation performance. The influence of slab thickness on flexural bearing capacity was most pronounced. Under identical reinforcement conditions， increasing the slab thickness from 40 mm to 55 mm resulted in a peak bearing capacity increase of approximately 44% for specimens with a 900 mm side length and about 31% for those with a 1250 mm side length. The calculation method， based on the equivalent cross-sectional model and plastic hinge theory， accurately predicts the ultimate flexural capacity of UHPC bidirectional thin slabs under concentrated loads， providing valuable reference for the design of UHPC thin plate formwork structures.