重复荷载下混凝土中钢筋锚固长度的理论分析.pdf

四川建筑科学研究
第39卷第6期
36
Sichuan Building Science
2013年12月
重复荷载下混凝土中钢筋锚固长度的理论分析
蒋德稳',邱洪兴2
(1.淮海工学院土木工程学院,江苏连云港222005
2.东南大学土木工程学院,江苏南京210096
摘要:为了研究重复荷载下混凝土中钢筋的临界锚固长度,首先运用粘结滑移基本微分方程,基于 Balazs静载下
局部粘结滑移本构关系推导了临界锚固长度理论解,分析了混凝土强度、保护层厚度和钢筋直径对静载下锚固长
度的影响;然后基于 Byung Hwan重复荷载下局部粘结滑移本构关系,根据粘结疲劳寿命基本理论,即当重复荷载
下钢筋滑移量增长到静载最大滑移量时发生粘结疲劳破坏,推导了重复荷载下粘结锚固长度公式,分析了应力水
平、应力循环次数对重复荷载下锚固长度的影响。研究表明:重复荷载下,由于粘结性能的退化,钢筋的临界锚固
长度应有所增加,在低应力水平下,重复荷载次数对锚固长度影响不大,在高应力水平下影响明显。研究结果可为
深入研究混凝土结构疲劳性能提供依据和方便。
关键词:锚固长度;粘结;滑移;钢筋混凝士
中图分类号:TU375.4
文献标志码:A
文章编号:1008-1933(2013)06-036-05
Theoretical analysis on anchorage length of bars in concrete
under repeated loading
JIANG Dewen, QIU Hongxing
(1. College of Civil Engineering, Huai-hai Institute of Technology, Lianyungang 222005, China
2. College of Civil Engineering, Southeast University, Nanjing 210096, China)
Abstract: In order to study the rebars critical length under repeated loading, according to the basic differential equation of the
relationship between bond stress and slip, the theoretical solution of the critical anchorage length was deduced based on Balazs's bond
slip basic constit utive relation moels under mno onic loading. T e fect of onree strength, thickness of concrete cover and rebar
diameter on anchorage length were analyzed. Based on Byung Hwan s bond-slip basic constitutive relation models under repeated
loading, the critical length of repeated loading was inferred according to Balazs's bond fatigue life theory(i.e., the condition of bond
fatigue damage is that slippage under repeated loading reach the maximum slippage under monotonic loading).The effect of stress
levels, repeated times on anchorage length were also analyzed. Research shows that the critical anchorage length under repeated loading
should be increased because of bond performance deterioration. Under low stress level, the repeated times have little influence on the
anchorage length, while the influence under high stress level is distinct. The results of the present study are expected to be useful for
thorough analysis of concrete structure's fatigue performance
Key words: anchorage length; bond; slip; reinforced concrete
言
力,使结构破坏。在通常情况下,纵向钢筋的承载受
力是通过一定长度上钢筋表面与握裹层混凝土的粘
钢筋和混凝土这两种材料能够共同工作,其中结锚固作用实现的。因此,锚固设计的关键是确定
很重要的一个原因是因为钢筋和混凝土之间有很好锚固长度。静载下,当错固抗力等于钢筋的屈服力
的粘结作用。当混凝土构件受到荷载作用时,在构时,相应的锚固长度为临界锚固长度,这是保证受力
件或结构的某些部位,钢筋和混凝土之间会产生相钢筋不发生锚固破坏的最小长度;当锚固抗力等于
对滑移,进而引起构件开裂或节点处的转角过大,影钢筋的极限拉力时,相应的锚固长度为极限锚固长
响结构的正常使用,严重者还会影响结构的承载能度,显然,超过此值的错固长度部分将不起作用'?
重复荷载下,由于粘结性能的退化,临界锚固长度
收稿日期:2012-04-2
极限锚固长度应有所增加。国内外试验表明3,高
作者简介:将德稳(1973-)ン,男,江苏盐城人,副教授,博士,主要从周疲劳荷载下,一般粘结疲劳发生之前,钢筋和混凝
事混凝土结构耐久性和疲劳性能研究。
基金项目:973项目(2007CB714200)
土就已经疲劳破坏了,所以,一般通过限制钢筋或混
E-mail:J5591371(@163.com
凝土的应力幅来防止粘结疲劳破坏,而没有采用增