钢筋及其锈蚀对混凝土构件阻尼的影响

EFFECT OF REINFORCEMENT AND CORROSION ON DAMPING CAPACITY OF CONCRETE MEMBERS

  • 摘要: 钢筋及其锈蚀将显著影响混凝土构件的动力特征参数。以纵筋配筋率、纵筋表面形式、箍筋间距、钢筋锈蚀率为主要参数,采用简支梁三点弯曲动态阻尼测试,研究各因素对弯曲小变形混凝土梁弹性阶段损耗因子与耗散模量的影响,探讨其作用机理,并对比分析构件刚度退化、阻尼演变随钢筋锈蚀率的变化规律。结果表明:损耗因子与耗散模量随配筋率增加先增加后减小,在配筋率为1%时达到峰值;损耗因子与耗散模量随钢筋锈蚀率增加先减小后增大,在锈蚀率为0.4%时达到最小值;损耗因子与耗散模量随箍筋间距的增大而减小;损耗因子与耗散模量按纵筋表面形式从大到小依次为月牙肋、光圆、方钢。随钢筋锈蚀率增加,阻尼比增长比刚度退化更显著,用阻尼参数探测钢筋混凝土构件的锈蚀损伤具有可行性。

     

    Abstract: Reinforcement and corrosion have a significant impact on the dynamic parameters of reinforcement concrete (RC) members. Taking the longitudinal reinforcement ratio, steel surface shape, stirrup spacing, and corrosion ratio as influencing factors, a three-point bending dynamic test was conducted to study the influence of aforementioned factors on the loss modulus and tangent of concrete under small bending deformation. The relationship between rigidity degeneration, damping evolution and corrosion ratio were also analyzed. The test results show that the loss modulus and tangent first increase with the reinforcement ratio and then tend to decrease. Their values reach a peak value around a 1% reinforcement ratio. On the contrary, loss modulus and tangent first decrease and then increase with a corrosion ratio. They get the minimum values around a 0.4% corrosion ratio. With regards to the stirrup spacing, loss modulus and tangent decrease monotonously with an increment in spacing. The crescent-ribbed, round, and rectangular bar used in concrete, has a decreasing enhancing effect for loss modulus and tangent. In addition, the corrosion ratio has an obvious impact on damping increment than rigidity degeneration. It indicates that the damping parameters of a corroded RC member are better to evaluate their damage level.

     

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