摘要
为了研究酸雨腐蚀环境下预应力混凝土T梁重载交通疲劳性能,对6根腐蚀预应力混凝土梁进行静载试验和等幅疲劳试验,利用显微镜观察钢筋疲劳断裂时的破坏形态,从而推出相应条件下钢筋破坏的几何模型。结果表明:腐蚀预应力混凝土梁的疲劳破坏以底部钢筋发生疲劳脆性断裂为标志;在疲劳加载过程中,预应力混凝土梁荷载-挠度曲线、混凝土、钢筋和钢绞线荷载-挠度曲线呈现“疏-密-疏”三段式变化;钢筋疲劳裂纹的发展规律与钢筋应变的变化相对应;相较于未腐蚀试件,腐蚀试件疲劳寿命降低了32.7%;疲劳上限值为0.45和0.6倍极限荷载时,预应力混凝土梁疲劳寿命均小于200万次,且相较于疲劳上限值为0.3倍极限荷载时分别下降69.3%、85.1%。
To investigate the effects of acid rain corrosion on the fatigue performance of prestressed concrete T-beams under heavy-duty traffic,six corroded beams were subjected to static load tests and constant amplitude fatigue tests.The microscopic morphology of the steel bars at the fatigue fracture locations was examined,and a geometric model of the steel bar failure under the corresponding conditions was established.The results showed that fatigue brittle fracture of the bottom steel bars was the main failure mode of all corroded prestressed concrete beams.The load-deflection curves of the prestressed concrete beams,as well as those of the concrete,steel bars,and steel strands,exhibited a three-stage variation of“sparse-dense-sparse”during the fatigue loading process.The evolution of fatigue cracks in the steel bars was consistent with the changes in steel strain.The fatigue life of the corroded beams was reduced by 32.7%compared to the uncorroded ones.When the fatigue upper limit value was 0.45 and 0.6 times the ultimate load,the fatigue life of the prestressed concrete beams was less than 2 million cycles,which was 69.3%and 85.1%lower than that when the fatigue upper limit value was 0.3 times the ultimate load,respectively.
作者
许开成
黄凌娟
杨宏宇
张立卿
易彬
陈梦成
XU Kaicheng;HUANG Lingjuan;YANG Hongyu;ZHANG Liqing;YI Bin;CHEN Mengcheng(The State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University,Nanchang 330013,Jiangxi,China;School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,Jiangxi,China)
出处
《实验力学》
CSCD
北大核心
2024年第2期248-260,共13页
Journal of Experimental Mechanics
基金
国家自然科学基金项目(51968021)
江西省自然科学基金项目(20224BAB204067)
轨道交通基础设施性能监测与保障国家重点实验室资助项目(HJGZ2022201)
江西省研究生创新专项资金项目(YC2022-s506)。
关键词
重载交通
预应力混凝土梁
酸雨腐蚀
等幅疲劳试验
疲劳寿命
heavy load traffic
prestressed concrete beam
acid rain corrosion
constant amplitude fatigueexperiment
fatiguelife
