UHPC加固损伤RC梁抗弯性能有限元分析研究

Finite Element Analysis Research on Flexural Behavior on the Damaged Reinforced Concrete(RC)Beam Strengthened by UltraHigh Performance Concrete(UHPC)

配筋超高性能混凝土(UHPC)具有优异的抗拉韧性、拉伸应变硬化性能和超强的耐久性,已有研究表明,将其用于加固钢筋混凝土(RC)结构,可使RC受损部位得到高强、耐久、低渗透的保护,大幅度提高RC结构强度、延长其使用寿命。但目前在这方面的具体研究还较为缺乏,加固梁的抗弯性能研究也未考虑RC梁损伤的影响,因此在RC梁损伤严重的情况下,其分析结果可能偏于不安全。设计了考虑RC损伤程度影响的两根试验梁,采用试验与有限元模拟相结合的方法研究配筋UHPC加固损伤RC梁的抗弯性能,并与完好RC梁进行对比分析。使用有限元软件进一步进行了参数分析,研究了RC梁混凝土强度等级、UHPC龄期和UHPC加固层配筋率的变化对配筋UHPC加固RC梁抗弯性能的影响。结果表明:有限元分析较好地符合试验结果;UHPC加固梁表现为典型的弯曲破坏,破坏前UHPC加固层与RC梁的整体工作性良好、未出现界面剥离破坏;损伤RC梁采用配筋UHPC层加固后,其抗裂能力和抗弯性均能大幅提升。

Reinforced ultra-high performance concrete(UHPC)exhibits excellent tensile strength,strain hardening,low permeability and super durability,using it to reinforce the damaged reinforced concrete(RC)structure can make the damaged parts of RC get high strength,durable and low penetration protection,greatly improve the strength of RC structure and prolong the service life.However,the specific research in this area is still relatively lacking,and most research on flexural performance of reinforced beams does not consider the influence of RC beam damage,so the analysis results may be unsafe in the case of serious damage of RC beams.In this paper,two test beams considering the influence of damage degree of RC are designed,and the bending performance of pre-damaged RC beams strengthened by reinforced UHPC is studied by the method of test and finite element simulation,and compared with intact RC beams.The influence of concrete strength grade,UHPC age and reinforcement ratio of UHPC reinforcement layer on the flexural performance of reinforced UHPC RC beams is studied by finite element.The results show that the finite element analysis is in good accordance with the test results;UHPC strengthened beams show typical bending failure,the working performance of UHPC strengthened beams is good before the failure,and there is no interface peeling failure;after the damaged RC beams are strengthened with reinforced UHPC layer,their crack resistance and bending resistance can be greatly improved.