摘要
反复荷载可导致钢筋与混凝土之间粘结的严重退化,尤其在混凝土中的钢筋受到腐蚀后。试验研究了不同腐蚀率的钢筋腐蚀对反复荷载作用下的粘结-滑移特性的影响。研究参数包括钢筋腐蚀率和侧向约束。先用加速腐蚀方法将埋置于混凝土中受侧向约束和无侧向约束的钢筋腐蚀至不同的腐蚀程度,再测定其在反复荷载作用下的粘结应力-滑移特性。试验结果显示,较低的钢筋腐蚀有助于减小反复荷载作用下粘结损失的幅度,但这种影响随着腐蚀率增大而减弱。卸载阶段的粘结应力水平仅为加载阶段的3/4。较之于受约束试件,无约束试件的粘结强度随腐蚀率减小更为显著。建立了粘结退化率来表示荷载作用下的粘结损失。较高腐蚀率主要在前5个加载循环引起较大的粘结退化,腐蚀的影响随荷载作用而减弱,同时,反复荷载作用下的粘结应力-滑移曲线与加载历史有关。
Cyclic loading can result in severe degradation of bond between reinforcing steel bar and the surrounding concrete, especially when the reinforcement is corroded. Tests have been carried out to evaluate the effect of reinforcement corrosion on bond under cyclic loading for different corrosion levels. Parameters investigated include corrosion level and lateral confinement. The embedded reinforcing steel bars, either laterally confined or unconfined, were corroded to different levels by accelerated corrosion method before being tested for bond stress-slip under cyclic loads. The results revealed that a low level of corrosion helped to reduce bond loss during loading. However, this effect was decreased as corrosion level increased. The bond capacity in unloading phase was only three-fourth of that in loading phase. Bond strength decreased more substantially as corrosion level increased in unconfined bars than in confined ones. The term
“bond degradation factor” was developed to represent the bond loss during loading. A higher level of corrosion caused bond degradation primarily in the initial five loading cycles, the effect of corrosion being decreased with loading. It was also demonstrated that cyclic bond stress-slip curve depended on loading history.
出处
《工业建筑》
CSCD
北大核心
2005年第12期15-18,22,共5页
Industrial Construction
基金
国家留学基金(编号:22831060)
瑞典政府SI基金(编号:200)资助
关键词
粘结强度
钢筋
混凝土
bond strength reinforcing steel concrete
作者简介
方从启 男 1963年3月出生 副教授博士
