重復荷載作用下CFRP布-混凝土界面黏結滑移模型
首發時間:2020-07-14
摘要:碳釬維增強復合材料(CFRP)-混凝土界面黏結-滑移關系是進行外貼CFRP加固混凝土結構受力分析的基礎。本文考慮重復荷載水平、混凝土強度、CFRP布與混凝土的寬度比和CFRP布黏結長度的影響,采用梁鉸式試件,進行CFRP布-混凝土界面性能試驗,研究靜力荷載和重復荷載作用下CFRP布-混凝土界面黏結-滑移本構關系。結果表明,隨著荷載循環次數的增加,CFRP布-混凝土界面黏結-滑移曲線不斷退化,曲線上升段的斜率和黏結強度也不斷降低,但對應于黏結強度的滑移量變化很小。在已有的單調荷載作用下黏結-滑移本構模型的基礎上,考慮荷載水平、混凝土強度、CFRP布與混凝土寬度比等因素的影響,提出了重復荷載作用下CFRP布-混凝土界面某確定位置處的黏結-滑移退化模型及模型曲線上升段斜率退化公式,并提出了CFRP布-混凝土界面剝離過程中黏結強度退化公式。
關鍵詞: CFRP加固 重復荷載 CFRP-混凝土界面 黏結-滑移模型 疲勞試驗
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Bond-slip model for CFRP sheets externally bonded to concrete under cyclic loading
Abstract:The bond-slip relationship between CFRP and concrete is the base of stress analysis of concrete structure strengthened by CFRP. In this paper, considering the influences of load level, concrete strength, CFRP-to-concrete width ratio and bond length of CFRP sheet, the CFRP-concrete interface characteristics tests were performed using hinged beam specimens to investigate the bond-slip constitutive relationship of CFRP-concrete interface under monotonic load and cyclic load. The results showed that as load cycles increased, the bond-slip curve of CFRP-concrete interface degenerated continuously, and the slope of the ascending section of the curve and the bond strength also decreased continuously, but the change of the slip corresponding to the bond strength was very small. Based on the existing constitutive bond-slip model under static load, considering the influences of load level, concrete strength, CFRP-to-concrete width ratio and so on, a bond-slip degradation model and a degradation formula of the slope of the ascending section of the model curve were proposed for a certain position of CFRP sheet-concrete interface under repeated load. In addition, a degradation formula of bond strength during the debonding process of CFRP sheet-concrete interface under repeated load were proposed.
Keywords: CFRP reinforcement cyclic load CFRP-concrete interface bond-slip model fatigue test
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重復荷載作用下CFRP布-混凝土界面黏結滑移模型
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