锈蚀箍筋矩形柱轴压承载力试验及理论研究

EXPERIMENTAL AND THEORETICAL STUDIES ON AXIAL COMPRESSION CAPACITY OF RECTANGULAR COLUMNS WITH CORRODED STIRRUPS

  • 摘要: 为探究箍筋锈蚀对钢筋混凝土矩形柱轴压性能的影响,以截面形状、箍筋布置、体积配箍率、锈蚀程度为变化参数,设计了27个钢筋混凝土矩形柱试件,并采用全浸泡电化学加速锈蚀法对其中的18个试件进行加速锈蚀。通过轴压试验研究了试件的破坏形态及各参数对其力-位移曲线的影响。结果表明:随着箍筋锈蚀率的增加,试件的初始刚度、极限承载力及延性均有所降低。试件的配箍率越低,其极限承载力降幅越显著。而后,基于锈蚀箍筋约束混凝土峰值应力、纵筋压屈模态下剩余承载力及保护层锈胀剩余承载力模型,建立了锈蚀箍筋约束混凝土矩形柱的极限承载力计算模型。通过预测值与试验值的对比,验证了模型的准确性与适用性。该模型可为锈蚀钢筋混凝土结构的剩余承载力的计算及安全评估提供指导。

     

    Abstract: In order to investigate the influence of stirrup corrosion on axial compression properties of reinforced concrete rectangular columns, 27 specimens were designed and tested. The variables include cross-sectional shapes, stirrup arrangements, volume stirrup ratios and corrosion degrees. The corrosion of stirrups was accelerated by the fully-immersed electro-chemical method. Failure modes and effects of variables on force-displacement curves of the specimens were studied through axial compression tests. Results show that with the increase of corrosion rate, the initial stiffness, bearing capacity and ductility of the specimens decrease. The decline of bearing capacity is more obvious with a lower stirrup volume ratio. Furthermore, the bearing capacity model for rectangular columns with corroded stirrups was established based on the maximum stress of the confined concrete, the residual bearing capacity of longitudinal reinforcement and the strength of concrete cover after corrosion. The accuracy and applicability of the proposed model were verified through a comparison between the predicted and experimental results. The proposed model can be used for the estimation of residual bearing capacity of corroded columns as well as the safety assessment.

     

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