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中南大学学报(自然科学版)

Journal of Central South University

第50卷    第1期    总第293期    2019年1月

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文章编号:1672-7207(2019)01-0180-09
多破坏模式和二次受力影响下FRP加固RC梁抗弯承载力
方圣恩1, 2,武棒棒1

(1. 福州大学 土木工程学院,福建 福州,350116;
2. 福州大学 土木工程防震减灾信息化国家地方联合工程研究中心,福建 福州,350116
)

摘 要: 针对实际工程应用中FRP加固RC梁存在多种破坏模式和二次受力影响等关键问题,提出采用能基本表征受压区混凝土实际应力-应变情况的Hognestad本构模型,以考虑受压区混凝土非线性应力变化。推导FRP加固RC梁受压混凝土等效应力和受压区高度各自对应的相关比值,并得出FRP拉断、钢筋屈服前、后受压区混凝土压碎这3种不同破坏模式下的梁正截面极限抗弯承载力计算公式,同时推导加固梁FRP最大、最小加固量的计算公式以定义各破坏模式间的临界状态,并考虑二次受力影响和滞后应变效应。研究结果表明:所推导的公式能有效表征加固梁的不同破坏模式及二次受力效应,所计算的承载力与试验值较吻合,可以用于RC梁加固设计和承载力分析。

 

关键字: FRP加固;Hognestad本构模型;破坏模式;二次受力;极限抗弯承载力

Ultimate load capacity of FRP-strengthened RC beams considering different failure modes and secondary loading effects
FANG Shengen1, 2, WU Bangbang1

1. School of Civil Engineering, Fuzhou University, Fuzhou 350116, China;
2. National and Local United Research Center for Seismic and Disaster Information of Civil Engineering,Fuzhou University, Fuzhou 350116, China

Abstract:With consideration of the different failure modes and the influence of secondary loading for FRP-strengthened RC beams, the Hognestad constitutive model that is close to actual stress-strain situations of concrete was used for the nonlinear changes in the compressive zone of concrete. The coefficients related to the equivalent stress of concrete under compression, as well as to the depth of compressive zone of concrete, were deduced based on the Hognestad model. Then the formulas of ultimate bending moments of RC beams were established with respect to three different failure modes i.e., FRP tensile failure, reinforcement yield before and after concrete crushing. Meanwhile, the maximum and the minimum FRP amounts for beam reinforcement were given to define the critical conditions between different failure modes. The secondary loading effects with lag strains were also involved in the context. Lastly, the proposed formulas were validated by using some tested FRP-reinforced RC beams. The results show that the proposed formulas consider different failure modes and the influence of secondary loading. The ultimate loads calculated with the formula are in agreement with the experiments results, which indicates that the formula can be used to design the FRP reinforcement and analyze the corresponding ultimate load of RC beams.

 

Key words: FRP reinforcement; Hognestad constitutive model; failure mode; secondary loading; ultimate bending moment

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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