The response of structures under rapidly varying loads can be affected by strain rate sensitivity generally expressed using Dynamic Increase Factor (). Current models for estimating the in Reinforced Concrete (RC) structures are generally deterministic and have restricted applicability due to their dependence on limited experimental data resulting in bias. This paper overcomes these limitations by proposing three probabilistic models that quantify compressive and tensile concrete and steel , accounting for the relevant uncertainties. The proposed models are based on existing deterministic models with the addition of probabilistic correction terms. Bayesian updating is employed to estimate the unknown model parameters using observational data from a large collection of experimental observations. The models incorporate model uncertainties stemming from assumed model form and (potential) missing variables through a model error term. The proposed probabilistic models are used to evaluate the reliability of RC structures under dynamic loads. As an illustration, the proposed probabilistic models are used to estimate the reliability of an example RC column under combined dynamic axial force and moment, and a RC column or beam under dynamic bending moments resulting in cracking. In the two examples, we consider the ACI 318-19 requirements for Ultimate Limit State (ULS) and Serviceability Limit States (SLS). In comparison to deterministic models, the proposed probabilistic models yield enhanced predictive accuracy, presenting a practical and robust approach to assess the structural reliability under impact and blast loads.

中文翻译：

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钢筋混凝土结构动态增加系数 (DIF) 的概率模型：贝叶斯方法

结构在快速变化的载荷下的响应可能会受到应变率敏感性的影响，通常使用动态增加因子 () 表示。目前用于估计钢筋混凝土（RC）结构的模型通常是确定性的，并且由于它们依赖于有限的实验数据而导致偏差，因此其适用性受到限制。本文克服了这些局限性，提出了三种量化混凝土和钢材的压缩和拉伸的概率模型，并考虑了相关的不确定性。所提出的模型基于现有的确定性模型并添加了概率校正项。贝叶斯更新用于使用大量实验观测数据中的观测数据来估计未知模型参数。这些模型通过模型误差项纳入了源自假设模型形式和（潜在）缺失变量的模型不确定性。所提出的概率模型用于评估动态载荷下钢筋混凝土结构的可靠性。作为说明，所提出的概率模型用于估计示例 RC 柱在动态轴向力和力矩组合下的可靠性，以及 RC 柱或梁在导致开裂的动态弯矩下的可靠性。在这两个示例中，我们考虑了 ACI 318-19 对极限极限状态 (ULS) 和适用极限状态 (SLS) 的要求。与确定性模型相比，所提出的概率模型提高了预测精度，提供了一种实用且稳健的方法来评估冲击和爆炸载荷下的结构可靠性。