UHPC-NC组合短柱轴压性能  

Axial Compression Performance of UHPC-NC Composite Short Columns

作　　者：梅葵花[1] 徐升宇 郭乐 周琪 孙胜江[1] MEI Kui-hua;XU Sheng-yu;GUO Le;ZHOU Qi;SUN Sheng-jiang(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;Shanxi Transportation Planning Survey and Design Institute Co.Ltd.,Taiyuan 030032,Shanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]山西省交通规划勘察设计院有限公司,山西太原030032

出　　处：《中国公路学报》2025年第3期354-366,共13页China Journal of Highway and Transport

基　　金：国家重点研发计划项目(2021YFB2601000);陕西省自然科学基础研究计划项目(2023-JC-YB-292)。

摘　　要：为有效提高桥梁墩柱结构的耐久性,通过使用超高性能混凝土(Ultra-high Performance Concrete,UHPC)约束普通混凝土(Normal Concrete,NC)形成一种新型的组合结构UHPCNC组合柱。对8根UHPC-NC组合柱、1根无箍筋保护层组合柱、1根无钢筋组合柱开展轴压试验,探究不同浇筑方式、UHPC厚度、箍筋间距以及有无钢筋对组合柱轴压性能的影响。结果表明:UHPC-NC组合柱达到峰值荷载时箍筋外侧UHPC仍保持一定的完整性,并未发生大面积剥落;浇筑方式对组合柱承载力影响较大,先浇筑内部NC后浇筑外部UHPC的方法能够使组合柱获得更大的承载能力;对于相同截面积的组合柱试件,其峰值荷载增加的相对幅值随UHPC厚度的增加而逐渐减小,当UHPC厚度分别由30mm增加到40mm,由40mm增加到50mm时,峰值荷载增加的相对幅值分别为11.8%和9.5%;箍筋间距对组合柱初期刚度几乎无影响,但组合柱峰值荷载随箍筋间距的减小而增大,当箍筋间距由60mm减小到40mm时,组合柱的峰值荷载提升了11.0%;为避免UHPC-NC组合柱发生脆性破坏,应在组合柱中配置螺旋箍筋。建立了与试验结果较为吻合的UHPC-NC组合柱有限元分析模型;基于轴压试验与数值模拟,引入了箍筋外侧UHPC强度折减系数α和浇筑方式影响系数β,提出的组合柱轴压承载力计算公式具有较高的精度,可用于UHPC-NC组合柱的轴压承载力计算。To effectively improve the durability of bridge pier column structures,a new type of composite structure,ultra-high-performance concrete(UHPC)normal concrete(NC)composite columns,was developed in this study.Axial compression tests were conducted on eight UHPCNC composite columns,one composite column without a stirrup protection layer,and one composite column without a steel bar.The effects of different casting methods,UHPC thicknesses,stirrup spacings,and steel bar arrangements on the axial compression performance of composite columns were investigated in this study.The results show that the UHPC outside the stirrup maintains a certain integrity,and no large-scale spalling occurs when UHPC-NC composite columns reach the peak load.The casting method significantly affects the bearing capacity of the composite columns.Casting the internal NC first and then casting the exterior UHPC can make the specimen increase its bearing capacity.For composite column specimens with the same cross-sectional area,the relative amplitude of the peak load increase gradually decreased with an increase in the UHPC thickness.When the UHPC thickness was increased from 30 to 40 mm and from 40 to 50 mm,the relative amplitudes of the peak load increase were 11.8%and 9.5%,respectively.The stirrup spacing had little effect on the initial stiffness of the composite column.However,the bearing capacity of the composite column increased with decreasing stirrup spacing.When the stirrup spacing was reduced from 60 to 40 mm,the ultimate bearing capacity of the specimen increased by 1l.0%.Spiral stirrups were arranged in the composite columns to avoid brittle failure of the UHPC-NC composite columns.A finite-element analysis model of the UHPC-NC composite column was established in this study.It produces results in good agreement with the experimental results.The strength reduction coefficient of UHPC outside the stirrup,α,and the influence coefficient of the casting method,β,were introduced based on the axial compression tests and numerical simulati

关 键 词：桥梁工程 超高性能混凝土 试验研究 轴压性能 组合结构 约束效应 承载力 

分 类 号：U444[建筑科学—桥梁与隧道工程]