In this work we follow a multiscale methodology to characterize the structural performance of post-tensioned steel fiber-reinforced concrete dry joints. At the material level, we use an experimentally validated lattice-particle model whose input parameters are the properties of the different phases themselves (i.e., mortar, aggregates, fibers) and mixing information. This model is used to obtain the mechanical properties used in the structural-level simulations of the joints in terms of constitutive laws. The structural analyses are performed using the concrete damage plasticity model, which allows us to quantify the effect of fiber addition on the shear strength of the dry joints and their ductility. Our simulations agree well with other macroscopic models in the case of plain concrete and show, once again, that the American Association of State Highway Transportation Officials (AASHTO) code overestimates the nominal shear capacity of multiple-keyed joints. Regarding the fiber addition, we observe that it promotes an important increase in the shear capacity, but the prestress level is still more relevant in this sense. Based on our simulations, we propose an updated shear capacity estimate accounting for the fiber volume fraction. Finally, a clear increase in the ductility of the joint is observed when the fiber volume content is increased.

中文翻译：

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钢纤维增强对后张干接头抗剪强度影响的多尺度分析

在这项工作中，我们遵循多尺度方法来表征后张紧的钢纤维增强混凝土干接缝的结构性能。在材料级别，我们使用经过实验验证的晶格颗粒模型，其输入参数是不同相本身（即砂浆，骨料，纤维）的特性和混合信息。该模型用于根据本构定律获得用于接头结构级模拟的机械性能。使用混凝土损伤可塑性模型进行结构分析，这使我们能够量化纤维添加对干接缝的剪切强度及其延展性的影响。在普通混凝土的情况下，我们的模拟与其他宏观模型非常吻合，并再次表明，美国国家公路运输官员协会（AASHTO）的代码高估了多键接头的名义剪切能力。关于纤维的添加，我们观察到它促进了剪切能力的重要提高，但是在这种意义上，预应力水平仍然更为重要。基于我们的模拟，我们提出了考虑纤维体积分数的更​​新的剪切容量估算值。最后，当纤维体积含量增加时，接头的延展性明显增加。我们提出了考虑纤维体积分数的更​​新的剪切容量估算值。最后，当纤维体积含量增加时，接头的延展性明显增加。我们提出了考虑纤维体积分数的更​​新的剪切能力估算值。最后，当纤维体积含量增加时，接头的延展性明显增加。