建筑结构学报2025，Vol.46Issue(2)：122-131,140,11.DOI:10.14006/j.jzjgxb.2024.0125
超高性能纤维混凝土外管-混凝土内柱组合短柱轴压性能研究
Mechanical performances of short UHPFRC-NSC columns under axial compression
摘要
Abstract
To enhance the mechanical performance of concrete columns in complex environments,a composite short column composed of ultra high performance fiber reinforced concrete(UHPFRC)outer tubes and wrapped normal strength concrete(NSC)inner columns was proposed and studied under full-section axial compression by macro and micro-scale experiments and theoretical calculations.Six NSC columns with a height of 300 mm,a diameter of 104 mm(designed compressive strength of 20 MPa,35 MPa and 50 MPa)and 18 UHPFRC-NSC composite columns(diameter of 150 mm,outer tube thickness of 23 mm and high-strength steel fiber volume fraction of 2％)were tested.It is found that the peak stress and strain of the composite columns with fibers in outer tubes are improved by up to 238％and 77％respectively compared with the NSC columns,and the end-hook fibers show better effects than the straight ones.To investigate the failure mechanisms,in-situ micro X-ray computed tomography(μXCT)tests were conducted on two half-sized UHPFRC-NSC(concrete strength grade C50)columns.The digital volume correlation technique was employed to the acquired series of 35 μm CT images to calculate 3D strain field evolution.It is observed that the outer tube exhibits splitting-shear failure before the shear failure occurs to the inner column.Additionally,based on the elasticity theory and the radial displacement compatibility condition at the interface between the outer tube and the inner column,the interfacial force equation was derived.The results demonstrate that the interfacial force is minimal and the constraint effect is negligible.According to the UHPFRC and NSC compression constitutive models,a design equation of compressive stress and strain was proposed for composite columns,whose results agree well with the experimental data.关键词
超高性能钢纤维混凝土/组合柱/X光计算断层扫描/原位加载试验/约束作用Key words
ultra high performance fiber reinforced concrete(UHPFRC)/composite column/micro X-ray computed tomography/in-situ loading test/confinement effect分类
土木建筑引用本文复制引用
姜韬,彭程明,田彤,杨贞军..超高性能纤维混凝土外管-混凝土内柱组合短柱轴压性能研究[J].建筑结构学报,2025,46(2):122-131,140,11.基金项目
国家自然科学基金项目(52173300). （52173300）
