Temperature influence on creep of reinforced concrete

abstract: The creep of concrete promotes strains over time in structural members kept under sustained load. It causes the stress decrease on the concrete and the steel stress increase in reinforced concrete members. The moisture content and temperature influence significantly such phenomenon. The creep strains model of the NBR 6118/2014 [1] is, applicable, solely, to those cases of constant stress magnitudes. Reinforced concrete members exhibit variations on the stress magnitudes and, in this way, requires the use of an alternative model for the prediction of the creep strains as the so known the State Model. This report refers itself to temperature influence analysis upon creep strains of reinforced concrete structural members. The results have revealed that temperature speeds up the creep effects and, in this way, the steel yielding caused by the stress increase on the reinforcement bars occurs at earlier ages.

摘要：混凝土徐变可使承受持续荷载的结构构件随时间产生应变。该现象会导致钢筋混凝土构件内混凝土应力降低、钢筋应力升高。含水率与温度对该徐变现象影响显著。NBR 6118/2014标准[1]提出的徐变应变模型仅适用于应力幅值恒定的工况。而钢筋混凝土构件的应力幅值往往存在变化，因此需采用替代模型开展徐变应变预测，即本次研究提及的状态模型（State Model）。本报告围绕温度对钢筋混凝土结构构件徐变应变的影响展开分析。研究结果表明，温度会加速徐变效应的发展，进而使得配筋因应力升高产生屈服的龄期提前。