Impoving Development Characteristics of Reinforcing Bars

目前的ASTM对钢筋几何形状的要求是在40多年前制定的，现在已纳入四个涉及钢筋的ASTM规范中。拟议的研究将应用最新的分析和测试技术来评估当前使用的和潜在的新的肋骨几何形状，并制定旨在获得最佳钢筋发展特征的建议。该计划将包括钢-混凝土界面相互作用的基础研究，应用非线性有限元分析来评估不同的肋骨几何形状，测试现有的模式和原型钢筋，设计和生产新模式的钢筋，并评估全尺寸结构构件中的钢筋。结构方面的考虑将包括近距离钢筋的相互作用的影响、拼接的行为以及直线发展、循环荷载、疲劳和断裂以及高强度混凝土。此外，还将考虑环氧涂层对结合强度的影响以及对环氧涂层的改性，例如添加磨粒。

The current ASTM requirements for reinforcing bar geometry were established over 40 years ago and are now incorporated in four ASTM specifications covering reinforcing bars. The proposed research will apply the latest in analysis and testing techniques to evaluate currently used and potential new rib geometries, and to develop recommendations aimed at obtaining optimum reinforcing bar development characteristics. The program will include a basic study of the interactions at the steel-concrete interface, apply nonlinear finite element analyses to evaluate different rib geometries, test existing patterns and prototype bars, design and produce reinforcing bars with new patterns, and evaluate the bars in full-size structural members. Structural considerations will include the effects of the interactions of closely spaced reinforcement, the behavior of splices as well as straight development, cyclic loading, fatigue and fracture, and high strength concrete. In addition the effects of epoxy coating on bond strength and modifications to epoxy coatings, such as the addition of grit, will be considered.