混凝土梁嵌粘混合FRP筋弯曲性能试验研究

分别在钢筋混凝土简支梁和连续梁的受弯区、负弯矩区表层嵌粘不同FRP筋材进行加固,进行单调加载弯曲试验,研究不同初始荷载、FRP筋种类对简支梁、连续梁嵌粘FRP筋后的特征荷载、应变、变形等的影响程度,记录加载过程中梁体裂缝扩展情况。结果表明:不同FRP筋混合嵌入加固混凝土梁,可显著提高简支梁、连续梁的抗弯承载力,改善使用阶段性能,与单一FRP筋材嵌粘加固相比,裂缝分布特征相似,延性更佳;在初始荷载未完全卸除时,混凝土梁表层嵌粘不同FRP筋的加固效果略逊于无初始荷载作用下的加固梁,不过效果仍比较理想,建议实际工程中尽可能卸除外部荷载后再进行嵌粘混合FRP筋加固。

FLEXURAL TESTS OF RC BEAMS STRENGTHENED WITH NEAR SURFACE MOUNTED MIXED FRP RODS

Reinforced concrete beams were strengthened with near surface mounted (NSM) fiber reinforced polymer (FRP) rods into pre-cut grooves at the flexural zone and negative moment zone for simple supported beams and continuous RC beams.Flexural tests were monotonically carried out with NSM CFRP/BFRP hybrid rods under various initial loading.Experimental phenomena were recorded under loading levels such as crack width,typical loads,strains of steel bar/FRP rods and deformation.Test results show that flexural performances are increased for simple-supported and continuous RC beams strengthened with NSM hybrid FRP rods,especially for flexural capacity and normal stage performance.In comparison with RC beams with NSM single FRP rods,similar crack development and displacement ductility are better for beams with NSM hybrid rods.For test beams under initial loading,strengthen effect is slightly worse than beams without initial loading.External load is suggested to be removed as much as possible in field structure member.