Croce Pietro, Formichi Paolo, Landi Filippo
Department of Civil and Industrial Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56122 Pisa, Italy.
Materials (Basel). 2022 Jan 26;15(3):951. doi: 10.3390/ma15030951.
Refined non-linear static or dynamic analyses are increasingly used to assess the behavior of new and existing reinforced concrete structures. To perform these analyses, an adequate knowledge of the force-displacement, bending moment-curvature, and bending moment-rotation curves of relevant parts of structural members is needed, and modeling the bond-slip correlation for steel rebars becomes fundamental. The paper presents the results of an experimental campaign on r.c. specimens under tension, aiming, differently from previous studies, to better reproduce the bond-slip relationship accounting for the local confinement and anchorage conditions of real structural members. Resorting to an original numerical procedure allowing us to predict the relative displacement between steel reinforcement and the surrounding concrete in a reinforced concrete element, once assigned the stress in the naked steel bar and the bond-slip law, the experimental results are compared with the numerical outcomes obtained by adopting codified bond-slip laws. The comparison highlights that experimental values of sliding are well below those that are commonly given in existing bond slip laws, such as that adopted by the CEB-FIP Model Code. A new bond-slip model, which is able to satisfactorily predict actual strain fields and slips along the investigated r.c. elements, is thus proposed with the final aim of extending its implementation into non-linear analyses of r.c. structures.
精细的非线性静力或动力分析越来越多地用于评估新建和既有钢筋混凝土结构的性能。为了进行这些分析，需要充分了解结构构件相关部分的力-位移、弯矩-曲率和弯矩-转角曲线，并且对钢筋的粘结-滑移相关性进行建模变得至关重要。本文介绍了对钢筋混凝土试件进行拉伸试验的结果，与以往研究不同的是，其目的是更好地再现考虑实际结构构件局部约束和锚固条件的粘结-滑移关系。借助一种原始数值程序，一旦给定裸钢筋中的应力和粘结-滑移规律，就能预测钢筋混凝土构件中钢筋与周围混凝土之间的相对位移，将试验结果与采用规范粘结-滑移规律得到的数值结果进行了比较。比较结果表明，滑移的试验值远低于现有粘结滑移规律（如CEB-FIP 模型规范所采用的规律）通常给出的值。因此，提出了一种新的粘结-滑移模型，该模型能够令人满意地预测沿所研究钢筋混凝土构件的实际应变场和滑移，最终目的是将其应用扩展到钢筋混凝土结构的非线性分析中。
