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Response of Reinforced Concrete Dapped-End Beams Exhibiting Bond Deterioration Subjected to Static and Cyclic Loading
Journal of Advanced Concrete Technology ( IF 1.6 ) Pub Date : 2021-05-22 , DOI: 10.3151/jact.19.536
Ajibola Ibrahim Quadri 1 , Chikako Fujiyama 2
Affiliation  

In existing bridge structures, reinforced concrete dapped-end beams/girders (RCDEB) are frequently subjected to service loadings that exceed their design capacity, due to increasing economic and population growth. Dapped-end beams are prone to the accumulation of water due to improper drainage and sealing of the joint, providing favorable conditions for corrosion due to the stagnation of chloride rich water from de-icing salts used on roads. The situation can get even worse when freezing and thawing due to extreme weather conditions is present. Due to difficulties in maintenance of the dapped-end regions, this often leads to the deterioration of the concrete around the recess and bond deterioration, which ultimately results in durability issues. Unfortunately, the performance of RCDEB exhibiting corrosion induced bond deterioration is still not well understood. Hence, experimental, and numerical investigations were conducted to understand better the response of RCDEB subjected to static and cyclic loading, with the presence of bond deterioration. Furthermore, the static capacity of the beam was adopted to consider the variable amplitude cyclic loading at an increment of 15% static capacity for every 20 cycles. The reliability of the numerical examination under the direct-path constitutive models of concrete was extended to the moving load scenario by applying a lower load amplitude than the static capacity. It is shown that the prominent failure mechanisms observed in both static and cyclic tests were diagonal tension and shear. Through numerical investigations, it is also shown that from the damage level developed in the RCDEB under the moving load at a relatively low magnitude, high stresses were found within a relatively short number of cycles, which raises a serious cause for concern.



中文翻译:

静力和循环荷载作用下粘结劣化的钢筋混凝土空心端梁的响应

在现有的桥梁结构中,由于经济和人口的增长,钢筋混凝土简支梁/大梁(RCDEB)经常承受超过其设计能力的服务载荷。由于接头排水和密封不当,端梁容易积水,由于道路上使用的除冰盐中富含氯化物的水停滞,从而为腐蚀提供了有利条件。当由于极端天气条件而出现冻结和解冻时,情况可能会变得更糟。由于维护端部末端区域的困难,这通常导致凹部周围的混凝土变质和粘结变质,最终导​​致耐久性问题。很遗憾,RCDEB表现出腐蚀引起的键变质的性能仍未得到很好的理解。因此,进行了实验和数值研究,以更好地理解RCDEB在静态和循环载荷下的反应,并且存在键变差的情况。此外,采用梁的静电容来考虑每20个周期以15%静电容为增量的可变幅度循环载荷。在混凝土的直接路径本构模型下,数值检验的可靠性通过施加比静态容量低的荷载幅度而扩展到了移动荷载场景。结果表明,在静态和循环测试中观察到的主要破坏机制是对角拉伸和剪切。通过数值研究

更新日期:2021-05-22
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