钢筋混凝土黏结滑移效应计算方法与应用

A calculation method and application of bond-slip effect of reinforced concrete

以钢筋混凝土(reinforced concrete,RC)结构中锚固区域的黏结滑移效应为研究对象,基于一致黏结滑移本构模型,根据微元法建立锚固区域控制方程,通过积分计算并考虑实际工程中的边界条件,解得钢筋应力-滑移关系解析模型,与既有拉拔试验数据对比,验证了该解析模型的可靠性。进而,基于OpenSEES有限元平台,将模型与零长度纤维截面单元嵌套,结合纤维梁柱单元,建立考虑钢筋黏结滑移效应的数值建模方法。通过与既有RC构件的拟静力试验及应用传统宏观本构的数值模型进行对比,从构件层面进一步对解析模型的可靠性进行验证。结果表明:提出的钢筋应力-滑移模型能较好的反映长锚固钢筋受拉时的滑移行为;应用钢筋应力-滑移模型的零长度纤维模型能较为准确地计算RC柱的滞回曲线,相较于应用传统宏观本构的数值模型,提高了RC柱刚度与强度及其退化规律的预测精度,且对于不同设计参数的RC构件,能够更加准确的表征不同加载状态下的钢筋滑移行为。

The bond-slip effect in the anchored region of a reinforced concrete(RC)structure was taken as the research object.Based on the uniform bond-slip constitutive model and the micro-element method,the governing equation of the anchored area was established,and the analytical model of stress-slip relationship of reinforcement was obtained by integral calculation and considering the boundary conditions in practical engineering.The reliability of the proposed model was verified by comparison with the existing pull-out test data.Furthermore,based on the OpenSEES finite element platform,the model in this paper was nested with a zero-length fiber cross-section element,and a fiber beam-column element was combined to establish a fiber numerical modeling method that considers the bond-slip effect of a steel bar.By comparing with the quasi-static test of existing RC members and the numerical model of the nested traditional macro-constitutive model,the reliability of the analytical model in this paper was further verified at the component level.Results show that the stress-slip model proposed in this paper can accurately reflect the slip behavior of long anchored reinforcement under tension.The zero-length fiber model using the proposed bar stress-slip model can accurately calculate the hysteresis curve of RC columns.Compared with the numerical model of the nested traditional macro-constitutive model,the prediction accuracy of RC column stiffness,strength and the degradation law of them can be improved.Moreover,for RC members with different design parameters,the sliding behavior of reinforcement under different loading conditions can be characterized more accurately.