【摘要】 为建立针对弯剪破坏钢筋混凝土矩形墩的滞回模型,基于既有试验结果,提出了桥墩破坏模式判别准则。基于Ibarra-Medina-Krawinkler模型,将弯剪破坏矩形墩骨架曲线简化成4段,推导出相应的解析计算公式。在滞回规则中引入捏拢效应参数和滞回性能退化参数,用于描述弯剪破坏桥墩的捏拢效应和滞回性能退化。利用低周反复加载试验,验证骨架曲线计算方法的正确性,给出了捏拢效应参数和滞回性能退化参数关于剪跨比的取值方法。利用振动台试验,对建议的滞回模型进行了验证。研究结果表明:利用剪跨比和体积配箍率构成的判别准则能够有效判别出钢筋混凝土矩形墩的破坏模式,按照现行规范规定执行,能够保证矩形墩不发生剪切破坏,但仍存在发生弯剪破坏的可能性;所提计算方法提供的骨架曲线与试验结果吻合较好;建议当剪跨比小于2时,捏拢效应参数取0.5,滞回性能退化参数取600;当剪跨比大于3时,捏拢效应参数取0.8,滞回性能退化参数取1 000;当剪跨比介于2和3之间时,捏拢效应参数和滞回性能退化参数进行线性插值。经验证利用建议的滞回模型计算动力响应时,计算结果与振动台试验结果整体上吻合较好。更多还原

【Abstract】 To establish the hysteretic model of reinforced concrete rectangular bridge columns with flexure-shear failure mode,a criterion was put forward to verdict different failure modes of bridge columns based on existing trial results.According to Ibarra-Medina-Krawinkler model,the skeleton curve of rectangular bridge columns with flexure-shear failure mode was simplified into four lines,and the corresponding analytical formulas were derived.Parameters were introduced to hysteretic rules to consider the pinching effect and hysteretic performance deterioration.Cyclic loading tests were used to verify the proposed method of skeleton curve,and a method was given to determine those parameters considering the pinching effect and hysteretic performance deterioration in regard to the aspect ratio.The proposed hysteretic model forrectangular bridge columns with flexure-shear mode was verified by results of shake table tests.The results show that the criterion expressed with the aspect ratio and volume ratio of transverse reinforcement can be effective to identify failure modes of reinforced concrete rectangular bridge columns.According to current codes,it is guaranteed that rectangular bridge columns will not fail in shear mode,but there is still the possibility of flexure-shear failure.The proposed method of skeleton curve can provide the results which have good agreement with trial results.It is suggested that when the aspect ratio is less than 2,the pinching effect parameter is taken as 0.5 and the hysteretic performance degradation parameter is taken as 600.When the aspect ratio is greater than 3,the pinching effect parameter is taken as 0.8 and the hysteretic performance degradation parameter is 1 000.When the aspect ratio is between 2 and 3,the pinching effect parameter and the hysteretic performance degradation parameter are linearly interpolated.Conducted on basis of the proposed hysteretic model,the results match well with results of shake table experiment on the whole,by dint of the dynamic analysis.更多还原