锈胀钢筋混凝土拱肋承载力试验与模拟

EXPERIMENTAL AND NUMERICAL STUDIES ON REINFORCED CONCRETE ARCH RIBS WITH CORROSION-INDUCED CRACKS

  • 摘要: 为研究锈胀损伤对钢筋混凝土拱肋极限承载力的影响,制作了4片钢筋混凝土圆弧拱肋,通过电化学快速锈蚀使其表面产生不同程度的锈胀裂缝,讨论了初始锈胀裂缝的分布情况,研究了锈胀拱肋的裂缝发展、不同位置处位移和应变、极限承载力及失效模式。试验结果表明:锈胀削弱了混凝土截面尺寸和刚度,降低了钢筋与混凝土间的粘结性,是承载力退化的主要原因之一;锈胀导致的拱肋极限承载力下降率约为60%;锈胀未改变拱肋的失效模式,所有拱肋均在一侧拱脚发生脆性破坏。在试验的基础上,建立了锈胀钢筋混凝土拱肋的有限元计算模型,由于RC拱肋存在大面积锈胀,模型中未考虑混凝土保护层的影响,计算结果和试验值较为接近,为日后有限元建模提供一定参考。

     

    Abstract: This paper aims to study the effect of cracking damage on the ultimate strength of reinforced concrete arch ribs. Four reinforced concrete arch ribs of a circular type were manufactured. An accelerated corrosion test was used to obtain different cracking levels on the concrete surface and the initial crack distribution was discussed. The crack propagation, the deflections and strains at different positions, the ultimate load bearing capacity, and the failure modes were also studied. The experimental results showed that corrosion-induced cracks decreased the concrete sectional size and the stiffness, resulting in a bond degradation between concrete and steel bars. Cracking damage is one of the key factors on the strength degradation of reinforced concrete arch ribs. The decreased ratio of the bearing capacity is about 60% of un-corroded arch ribs. Cracking damage did not change the failure modes of arch ribs. All specimens occurred a brittle fracture at an arch spring. Based on the experimental results, a finite element model was established, neglecting the effect of concrete cover due to severe cracking. The calculated results agreed well with the experimental observations, which provided a reference for future finite element modelling.

     

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