基于光纤光栅传感技术的重载铁路预应力混凝土梁疲劳损伤试验研究  

Fatigue damage experiments of heavy haul railway prestressed concrete beams using fiber bragg grating sensing technology

作　　者：宋力[1,2] 余志武 SONG Li;YU Zhiwu(School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Laboratory for High Speed Railway Construction,Changsha 410075,China)

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：《建筑结构学报》2019年第1期58-66,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51378506;51778631);高铁联合基金重点项目(U1434204)

摘　　要：基于现有的一般测试方法,结合光纤光栅传感技术,提出了重载铁路预应力混凝土梁疲劳试验测试方法,并通过2根大比例模型梁验证了光纤光栅传感技术在预应力混凝土梁疲劳试验中应用的可行性。试验结果表明:光纤光栅传感器和FRP智能筋表现出精度高、量程大、稳定性好、耐疲劳等优点,在疲劳试验全过程中能够有效测试钢筋与预应力筋的应变;在33 t及以上轴重列车荷载长期作用下,32 m普通高度全预应力混凝土T形截面梁存在较大的疲劳开裂风险,其疲劳损伤破坏始于最外侧普通钢筋的疲劳破坏断裂,疲劳损伤开裂会引起梁的刚度明显降低和钢筋应力幅显著增加,大大缩短了梁的疲劳寿命。从安全和使用角度考虑,应严格控制该类型重载铁路预应力混凝土梁开裂及最大裂缝宽度。The fatigue testing method of heavy haul railway prestressed concrete beam was proposed based on the existing general test method and the fiber bragg grating (FBG)sensing technology.The feasibility of incorporating FBG sensing technology into fatigue tests of prestressed concrete beams was discussed using the results from two largescale model beam fatigue tests.The test results show that FBG sensors and fiber reinforced polymer (FRP)intelligent bars have the advantages of high accuracy,large range,good reliability,and that the fatigue resistance and the strain of steel bars can be obtained effectively in the full fatigue test.Under long-term loading of 33t or above axle weight trains,normal height fully prestressed concrete beams with a span of 32 meters are subject to a great risk of fatigue cracking.Fatigue failure of the beams is caused by rupture of the non-prestressed reinforcing bars.The fatigue damage crack causes significant decrease in the stiffness and fatigue life,and significant increase in the stress range of steel bar.To ensure the safety and to control the deformation of heavy haul railway bridges,the cracking and maximum crack width of the beams should be limited strictly.

关 键 词：重载铁路桥梁 预应力混凝土梁 疲劳试验 光纤光栅传感技术 

分 类 号：U239.4[交通运输工程—道路与铁道工程] TU378.2[建筑科学—结构工程]