普通钢筋锈蚀后预应力混凝土桥梁疲劳试验研究  

Experimental Study on Fatigue Behaviors of PC Bridge Beams with Corroded Steel Bars

作　　者：余志武[1,2] 李进洲[1,2] 宋力[1,2] 

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]高速铁路建造技术国家工程实验室,湖南长沙410075

出　　处：《公路交通科技》2014年第4期64-72,93,共10页Journal of Highway and Transportation Research and Development

基　　金：国家高技术研究发展计划(八六三计划)资助项目(2009AA11Z101)

摘　　要：借助传统应变片和891拾振器的疲劳试验实时测试系统,通过9片1/6缩尺模型梁疲劳试验,研究了普通钢筋锈蚀后预应力混凝土桥梁疲劳破坏形态以及振幅、刚度、非预应力筋和预应力筋应变、混凝土应变随重复荷载次数的变化规律。研究表明:梁底普通钢筋锈蚀后(预应力筋不锈蚀),只要钢筋没有发生锈蚀断裂破坏,混合配筋合适的预应力混凝土梁的静载承载力与普通没有锈蚀梁的承载力相差不大。锈蚀率超过一定界限后(20%),钢筋在坑蚀处断裂,梁的静载承载力会急剧降低,表现为少筋梁的脆性破坏特征。疲劳反复荷载作用下构件的中性轴位置基本保持不变,不像非锈蚀试件那样呈现出明显的3阶段变化过程;锈蚀率超过7%以后,容许疲劳疲劳寿命会急剧减少,达40%左右。A corrosion fatigue real-time testing system is built on the traditional strain gauge and 891-II vibration pickup. Based on the test of a total of 9 1/6-scale PC model beams, the developments of corrosion fatigue failure pattern, the vibration amplitude, the stiffness of ordinary steel bars, the strains of prestressed and non-prestressed steel bars and concrete with loading cycle frequency of increasing fatigue of PC bridge are studied. The results indicate that （1） to the PC beams with right mixed-reinforcement, there is no difference between the usual static bearing capacity and the corrosion static bearing capacity if the bottom corroded steel bars （the prestressing tendons have no corrosion） are not broken; （2） when the corrosion rate is above a certain limit （20%）, corrosion cracking may occur to the bottom steel bar pits and brings about a free fall in the bearing capacity, and the beams may represent a fracture failure of rare-reinforcement beams; （3） under repeated fatigue loading, the cross-sectional neutral axis of corrosion beams remain largely unchanged, which is unlike the usual beams that have experienced 3 main stages; （4） after the corrosion rate is more than 7 %, the allowable fatigue life of the beams have a drastic reduction by about 40%.

关 键 词：桥梁工程 预应力混凝土梁 钢筋锈蚀 疲劳试验 疲劳寿命 

分 类 号：U448.35[建筑科学—桥梁与隧道工程]