摘要
基于钢筋混凝土梁加固工程中存在的难以完全卸载后再补强的问题,研究考虑二次受力的钢筋混凝土梁采用预应力碳纤维复合增强材料(carbon fibre-reinforced polymer,CFRP)加固后的抗弯刚度和承载能力。采用软件ABAQUS建立加固梁的有限元分析模型,对比模拟结果与试验结果,验证模型的准确性;对考虑环境影响下不同配筋率、CFRP用量、混凝土强度等级、预应力和初始荷载的加固梁进行数值分析。结果表明:有限元模型模拟结果与试验结果基本一致,钢筋和CFRP荷载-应变曲线基本一致,模型的准确性较高;在加载初期至钢筋屈服前,不同配筋率、混凝土强度等级、CFRP用量等3个变量下,试验梁跨中位移相差较小,钢筋屈服后,随3个变量的增大,荷载-位移、荷载-应变曲线的斜率越大,位移增大的速度越慢;预应力比例越大,破坏时位移越小,预载比例越大,破坏时位移越大;相同荷载状态、高温高湿环境下,黏结界面损伤程度更大,界面损伤增速比室温环境明显快,剥离开始位置仍为跨中两侧,与低温环境时一致;CFRP应力以跨中位置为轴线向两侧对称分布,跨中区域应力较大,靠近锚固端应力水平逐渐降低,高温高湿环境下结构破坏时,位移减小。
Based on the issues encountered in actual building reinforcement projects,where it is difficult to completely unload before strengthening,this study investigates the flexural stiffness and load-bearing capacity of reinforced concrete beams subjected to secondary loading after being strengthened with prestressed carbon fibre-reinforced polymer(CFRP).A finite element analysis model for the strengthened beams is established using the software ABAQUS,and the simulation results are compared with experimental results to validate the accuracy of the model.Numerical analyses are conducted on the strengthened beams considering environmental influences,different reinforcement ratios,CFRP quantities,concrete strengths,prestress levels,and initial loads.The research findings indicate that the simulation results of the finite element model are generally consistent with the experimental results,with similar load-strain curves for both the steel reinforcement and CFRP,thereby validating the model′s accuracy.In the initial loading stage before the yielding of the steel reinforcement,the mid-span displacements of the experimental beams are relatively small for different reinforcement ratios,concrete strength grades,and CFRP quantities.After the yielding of the steel reinforcement,as the three variables increased,the slopes of the load-displacement and load-strain curves became steeper,and the rate of displacement increase slowed down.A higher prestress ratio results in smaller displacements at failure,while a higher preloading ratio led to larger displacements at failure.Under the same load conditions and in high-temperature and high-humidity environments,the degree of damage at the bonding interface is greater,with the damage rate accelerating significantly compare to room temperature conditions.The initiation of delamination still occurs at the mid-span regions,consistent with observations in low-temperature environments.The stress in CFRP is symmetrically distributed about the mid-span,with higher stress levels in the mid-sp
作者
唐守靖
杨莉萍
吴亚成
李亲青
TANG Shoujing;YANG Liping;WU Yacheng;LI Qinqing(Suzhou University of Science and Technology,Suzhou 215009,China;CSCEC International Construction Co.,Ltd.,Suzhou 215011,China)
出处
《山东交通学院学报》
CAS
2024年第4期100-108,共9页
Journal of Shandong Jiaotong University
基金
江苏省研究生科研与实践创新计划项目(KYCX21_3027)。
关键词
加固
预应力CFRP
二次受力
环境影响
reinforcement
prestressed CFRP
secondary loading
environmental impact
