Sakalauskas Karolis, Kaklauskas Gintaris
Department of Reinforced Concrete Structures and Geotechnical Engineering, Vilnius Gediminas Technical University, Vilnius, Lithuania.
Sci Rep. 2023 Aug 24;13(1):13883. doi: 10.1038/s41598-023-41080-x.
Reinforcement corrosion in concrete structures with excessive crack width poses a high risk of reducing the structure's service life. The crack width behavior is one of the most complex aspects of the mechanics of reinforced concrete (RC). With most of the models used in practice being semi-empirical or empirical, very few analytical approaches have been proposed. However, the analytical models lack either accuracy or simplicity, or both. This paper presents a new analytical model, termed the Pure Shear Model, that predicts mean crack width by a simple formula. It is based on the partial interaction tension stiffening model considering a short RC tie subjected to short-term loading. The model assumes elastic material properties and neglects shrinkage, internal cracking, and slip at the interface. It presumes that the only deformations that occur in concrete are the shear strains due to shear lag that are taken constant across the cover thickness. Deplanation of concrete section due to shear lag results in crack width linearly increasing from zero at the bar to its maximum value on the surface of the RC member. Despite the simplicity of the proposed model, its accuracy in predicting mean crack width was shown to be comparable to that of the design code methods.
在裂缝宽度过大的混凝土结构中，钢筋锈蚀会严重缩短结构的使用寿命。裂缝宽度特性是钢筋混凝土（RC）力学中最复杂的问题之一。目前实际应用的大多数模型都是半经验或经验模型，很少有解析方法被提出。然而，这些解析模型要么缺乏准确性，要么缺乏简单性，或者两者都缺乏。本文提出了一种新的解析模型，称为纯剪切模型，该模型通过一个简单的公式预测平均裂缝宽度。它基于考虑短期加载的短RC拉杆的部分相互作用拉应力强化模型。该模型假定材料为弹性性质，忽略收缩、内部开裂和界面处的滑移。它假定混凝土中发生的唯一变形是由于剪滞引起的剪应变，且在保护层厚度范围内保持恒定。由于剪滞导致混凝土截面的展开，使得裂缝宽度从钢筋处的零值线性增加到RC构件表面的最大值。尽管所提出的模型很简单，但其预测平均裂缝宽度的准确性与设计规范方法相当。
