摘要
针对腐蚀导致预应力筋与混凝土间黏结性能退化而引起的变形不协调对构件承载力的影响,结合8片梁的抗弯试验,通过定义变形协调系数表征腐蚀预应力筋与混凝土的应变比,进而量化变形协调性能,构造新的几何关系和平衡方程,推导变形协调系数及构件受弯承载力的表达式,探讨了预应力筋与混凝土间变形协调系数随各影响因素的变化规律,并通过与相关文献试验结果的对比进行了验证。结果表明:腐蚀会引起预应力筋与混凝土间变形协调性下降,极限荷载时,变形协调性的退化使构件承载力降低,考虑腐蚀预应力筋与混凝土间的变形不协调,有助于提高承载力的计算精度;变形协调系数随腐蚀率、梁高、梁宽和混凝土强度增加而增大,随预应力筋重心至梁底距离增加而减小。
This paper is aimed at making an investigation of the impact of the corrosioninduced inconsistent compatibility between the strand and concrete on the flexural behavior of PC beams. In proceeding with our research, we have, first of all, designed and subjected eight PC beams to the accelerated corrosion in different strandcorrosion degrees. Secondly, we have done a flexural test on the beams with a discussion of the load deflection response and its ultimate strength. After that, a compatibility coefficient has been introduced to make a quantitative study on the inconsistent compatibility between the strand and the adjacent concrete part, all of which let us establish the new compatibility equation and the equilibrium equation while taking into account the compatibility coefficient. Following this, we have derived a successful model on the compatibility coefficient, which helps us to find the impact of the strand corrosion on the compatibility coefficient. And, finally, we have brought about an analyti cal model to predict the ultimate strength of the PC beams with the corroded strand. What we intend to do is to make the proposed ultimate strength model include the area loss and the yield strength degradation induced by the strand corrosion, as well as the compati bility coefficient. Hence, we have verified the accuracy of the said model through the experimental results in the present study with other necessary items of reference, in which the predicted ultimate strengths turn to be well in accord with the experimental data. However, the results prove that the compatibility between the strand and the concrete is inconsistent with the bond performance degradation caused by the strand corrosion. Later, we have found that the deformation compatibility degradation may lead to a significant decrease of the ultimate strength. Thus we believe that the inconsistent compatibility between the strand and the concrete can on the contrary help to improve the predicted accuracy of the ultimate strength, for the reason that the compatibility coefficient tends to increase with the in crease of the parameters in the ultimate state, such as the width and the height of the PC beam, the corrosion loss and that of concrete strength, which are likely to decrease with the increase of the dis tance between the strands and the bottom of the PC beam.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第4期5-10,共6页
Journal of Safety and Environment
基金
国家自然科学基金项目(51178060)
湖南省自然科学杰出青年基金项目(14JJ1022)
湖南省大学生研究性学习和创新性实验计划项目(3020102-1203015)
湖南省研究生科研创新项目(CX2014A015)
关键词
安全工程
工程结构
预应力混凝土
腐蚀
黏结性能
变形协调性
抗弯承载力
safety engineering
engineering structures
prestressed concrete
corrosion
bonding performance
compatibili- ty
flexural strength
