摘要
采用内填混凝土加固钢管轴压构件时,由于负载下的钢管一般处于不同的初应力水平,需要研究初应力对构件加固后承载力的影响。对15根不同长细比和初应力比的钢管进行了内填混凝土加固,并对构件加固后的轴压性能进行了试验研究。试验结果表明:钢管初应力对钢管混凝土轴压试件的破坏形态无影响;当长细比为16时,钢管初应力变化对内填混凝土加固钢管试件的承载力影响较小;当长细比为40,60时,初应力比的增大会显著降低加固试件的轴压承载力,影响内填混凝土法的加固效果,最大降幅达到27%。将试验结果与国内外主要设计规范的计算结果比较表明,当初应力比小于0.6时,GB 50936—2014、CECS 28:2012和EN 1994-1-1设计公式的计算结果与试验数据吻合较好,ANSI/AISC 360-10和AIJ-CFT规范中公式的计算结果偏于保守;而当初应力比超过0.6时,ANSI/AISC 360-10提出的公式较为保守,GB 50936-2014、CECS 28:2012、EN 1994-1-1、AIJ-CFT规范中公式的承载力计算结果则偏于不安全。
The steel tubes under axial compression,with different initial stresses,can be reinforced by infilling concrete. The influences of initial stresses on the axial bearing capacity after reinforcement should be considered. A total of 15 steel tube test specimens with different slenderness ratios and initial stress ratios were reinforced,and the behavior after infilling concrete was experimentally studied. The results show that: the initial stresses of the steel tubes have no influence on the ultimate failure modes; when the slenderness ratios is 16,the initial stresses of the steel tubes have little impact on the axial strength of the concrete filled steel tubes. However,when the slenderness ratios are 40 and 60,the axial bearing capacity can be severely reduced by the increase of initial stress ratios,and the maximum reduction range is 27%. Meanwhile,the obtained test results are used to compare with the predicted results from currently available design standards. For the test specimens with initial stress ratios lower than 0. 6,it can be seen that the predictions of bearing capacity from GB 50936—2014,CECS 28: 2012 and EN 1994-1-1 have good agreement with the test data,while the design standards ANSI / AISC 360-10 and AIJ-CFT may underestimate the capacities. While for the test specimens with higher initial stress ratios( higher than 0. 6),overpredicted results may be obtained from the three design standards GB 50936—2014,CECS 28: 2012,EN1994-1-1 and AIJ-CFT.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2015年第S2期22-27,共6页
Journal of Building Structures
基金
湖北省自然科学基金面上项目(2014CFB715)
国家自然科学基金项目(51508424)
关键词
钢管混凝土
初应力
加固
轴压试验
轴压承载力
CFST
initial stresses
axial compression test
strenghened
axial bearing capacity
