摘要
为评估事故条件下核电站堆腔在热力耦合作用下的剪切破坏风险,采用条带化模型设计1∶4缩尺RC梁,开展室温、100℃和150℃条件下一端固接、一端铰接的非对称约束RC梁四点加载试验,分析了热力耦合作用下试验梁荷载-位移曲线、裂缝开展及分布规律、温度分布规律、钢筋应变演变规律和剪切破坏形态等。试验结果表明:试验梁在固接端剪跨段发生斜压脆性破坏,破坏时承载力迅速下降,混凝土大面积剥落,试验梁无法继续承载;与室温加载梁相比,100~150℃范围内高温作用虽然能够延缓斜向剪切裂缝发展、降低试验梁挠度,但是其增大弯曲裂缝的宽度、降低试验梁的极限承载能力。此外,综合考虑热力耦合作用及非对称约束条件影响,提出了改进的压杆-拉杆模型(MSTM),用以评估热力耦合作用下非对称约束超静定钢筋混凝土梁的受剪承载力,计算结果与试验结果吻合良好(平均误差5.93%)。
To assess the shear failure risk of nuclear power plant reactor cavity under accident conditions considering thermal-mechanical coupling effects,1∶4 scale reinforced concrete(RC)specimens were designed using a strip model.Asymmetrically constrained RC beams,fixed at one end and hinged at the other,were subjected to four-point bending tests at room temperature,100℃and 150℃.The load-displacement curves,crack development and distribution patterns,temperature distributions,rebar strain evolution,and shear failure modes under thermalmechanical coupling were analyzed.The results reveal that the test beams experience oblique compression brittle damage in the shear span section at the fixed end,with a rapid decrease in load-bearing capacity and extensive concrete spalling,rendering them incapable of further load bearing.Compared to specimens tested at room temperature,those exposed to temperatures 100-150℃show delayed development of diagonal shear cracks and reduced deflection but exhibit wider bending cracks and decreased ultimate load capacity.Furthermore,a modified strut-and-tie model(MSTM)considering thermal-mechanical coupling and asymmetric constraint effects was proposed to assess the shear resistance of asymmetrically constrained statically indeterminate RC beams.The calculated results closely match experimental results(average error of 5.93%).
作者
陈圣刚
陈江涛
周传波
郭俊营
李贤
无
CHEN Shenggang;CHEN Jiangtao;ZHOU Chuanbo;GUO Junying;LI Xian;无(School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China;China Nuclear Power Design Co.Ltd,Shenzhen 518031,China;Jiangsu Key Laboratory of Disaster Impact and Intelligent Prevention in Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China)
出处
《建筑结构学报》
北大核心
2025年第9期232-241,共10页
Journal of Building Structures
基金
“十三五”国家重点研发计划(2019YBF1900903,2020YFB1901500)
国家自然科学基金项目(51808258)。
关键词
钢筋混凝土梁
非对称约束
热力耦合
受剪试验
改进压杆-拉杆模型
reinforced concrete beam
asymmetric restraint
thermal-mechanical coupling
shear behavior test
modified strut-and-tie model
