For reinforced concrete members subjected to high temperature, the degree of in-service loading, commonly expressed as the loading ratio, can be highly influential on the structural behavior. In particular, the loading ratio may be pivotal in relation to the phenomenon of load-induced thermal strain. Despite its potentially pivotal role, to date, the influence of the loading ratio on both material and structural behavior has not been explored in detail. In practice, real structures experience variation in imposed loading during their service life and it is important to understand the likely response at elevated temperatures across the loading envelope. In this paper, the effect of the loading ratio is numerically investigated at both material and structural level using a validated finite element model. The model incorporates a proposed constitutive model accounting for load-induced thermal strain and this is shown to outperform the existing Eurocode 2 model in terms of accuracy. Using the validated model, the specific case of flats slabs and the associated connections to supporting columns at various loading ratios are explored. For the cases examined, a marked difference in the structural behavior including displacement direction was captured from low to high loading ratios consistent with experimental observations.

中文翻译：

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加载比对平板平板连接温度升高的影响：数值研究

对于承受高温的钢筋混凝土构件，在役载荷的程度（通常表示为载荷比）可能会对结构性能产生很大影响。特别地，负载率相对于负载引起的热应变现象是关键的。尽管具有潜在的关键作用，但迄今为止，尚未详细研究载荷比对材料和结构行为的影响。实际上，实际结构在使用寿命期间会经受强加载荷的变化，因此了解整个载荷范围内在高温下可能产生的响应非常重要。在本文中，使用经过验证的有限元模型在材料和结构水平上均对载荷比的影响进行了数值研究。该模型包含了一个拟议的本构模型，该模型考虑了负载引起的热应变，并且在准确性方面已显示出优于现有的Eurocode 2模​​型。使用经过验证的模型，研究平板的具体情况以及在各种载荷比率下与支撑柱的关联连接。对于所检查的情况，从低到高的加载比捕获了与位移观察一致的结构行为（包括位移方向）的显着差异。