长江科学院院报

• 水工结构与材料 • 上一篇    下一篇

钢筋混凝土三点弯曲梁断裂韧度计算模型

胡少伟1,米正祥1,范向前2,陆俊1   

  1. 1.南京水利科学研究院 材料结构研究所,南京   210029; 2.河海大学 力学与材料学院,南京   210024
  • 收稿日期:2012-02-29 出版日期:2013-03-01 发布日期:2013-03-26
  • 通讯作者: 米正祥(1987-),男,甘肃广河人,硕士研究生,主要从事工程结构与材料研究
  • 作者简介:胡少伟(1969-),男,河南杞县人,教授级高级工程师,博士,主要从事工程结构与材料研究
  • 基金资助:

    水利部公益行业专项(201201038);水利部前期项目(S409001)

A Model for Predicting the Fracture Toughness of Reinforced Concrete Beam in Three-Point Bending

HU Shao-wei1, MI Zheng-xiang1, FAN Xiang-qian2, LU Jun1   

  1. 1.Material and Structural Engineering Department, Nanjing Hydraulic Research Institute, Nanjing   210029, China; 2.College of Mechanics and Materials, Hohai University, Nanjing   210024, China
  • Received:2012-02-29 Online:2013-03-01 Published:2013-03-26

摘要:

基于虚拟裂缝模型,针对钢筋混凝土试件在三点弯曲作用下开裂截面的受力特征,在合理假定的前提下,给出了一种计算钢筋混凝土三点弯曲梁的失稳断裂韧度的解析方法。然后,应用该方法计算了初始缝高比 α0(初始裂缝长度与试件高度的比值)分别为0.2,0.3,0.4,0.5的三点弯曲试件的最大荷载和临界有效裂缝长度,进而求得了钢筋混凝土三点弯曲梁的失稳断裂韧度。通过对计算结果与试验数据的误差分析,发现失稳断裂韧度最大误差为4.915%,说明这种方法可以较为准确地预测三点弯曲梁的失稳断裂韧度。在此基础上研究了初始缝高比 α0对失稳断裂韧度的影响,发现失稳断裂韧度基本上不随 α0 变化,失稳断裂韧度可以作为材料常数,应用于裂缝扩展状态的判断。

关键词: 钢筋混凝土, 失稳断裂韧度, 初始缝高比, 最大荷载

Abstract:

On the basis of fictitious crack model, an analytical method to calculate the fracture toughness of reinforced concrete was proposed under reasonable hypothesis by analyzing the mechanical characteristics at the cracked section of a specimen in three-point bending. The method was used to calculate the maximum load, critical effective crack length and in turn the fracture toughness of reinforced concrete beams in three-point bending whose  α0 (ratio of initial crack length to specimen height) were 0.2, 0.3, 0.4 and 0.5 respectively. The maximum error of unstable fracture toughness was 4.951% by comparing calculation results with test data. The results indicated that the method could predict the unstable fracture toughness precisely. Furthermore, the impact of  α0 on the unstable fracture toughness was studied. It was found that the unstable fracture toughness generally did not vary with α0, thus could be regarded as material constant to determine whether a crack will propagate.  

Key words:  reinforced concrete, unstable fracture toughness,  initial crack height ratio, maximum load         

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