UHPC薄板屈曲试验及临界板厚比研究

UHPC材料是一种新型纤维增强水泥基复合材料,利用材料强度高的特点设计建造桥梁通常为薄壁箱形结构,薄壁箱梁存在剪力滞效应、扭转畸变、翘曲失稳等问题。为研究UHPC箱梁顶板翘曲失稳,指导UHPC薄壁箱梁结构避免局部失稳破坏先于材料强度破坏,进行不同边界条件均布加载的19个UHPC薄板屈曲荷载试验研究。结果表明:UHPC板的屈曲主要有局部受压破坏、单方向裂缝破坏和双向裂缝破坏3种;屈曲荷载计算应引入材料和制作修正系数0.7;UHPC板最大幅值位于h/2高度,并只产生一个半波。最后对屈曲荷载试验值进行有限元计算分析对比,并通过欧拉公式推导UHPC箱梁顶板的临界板厚比限值。

Research on Buckling Test of UHPC Thin Plate and Critical Thickness Ratio

UHPC is a new fiber enhancement cement-based composite material with ultra-high mechanical property. The UHPC bridge is usually manufactured into thin-walled box structures, but there exist such defects as shear lag effect, twist distortion, and warping and instability in thin-walled box girder. In order to study the warping and instability of UHPC box girder roof, guide the UHPC thin-walled box girder structure to avoid local instability prior to the failure of material strength, buckling experiment of 19 UHPC plates with uniformly distributed load under different boundary conditions is conducted. The results show that the buckling of UHPC plates mainly falls into 3 types: local compression failure, single direction crack failure and two-way fracture failure; the calculation of buckling load should be made with material and correction coefficient 0.7; the maximum amplitude of UHPC board is at h/2 height, and only half wave is generated. Finally, the finite element analysis and comparison of the buckling load test values are carried out, and the critical plate thickness ratio limit of the UHPC box girder roof is deduced by Euler formula.