摘要
FRP(fiber reinforced polymer)片材增强钢筋混凝土梁纵筋屈服前刚度是其正常使用阶段的刚度,而纵筋屈服后刚度(又称二次刚度)则能够控制超载情况下梁的变形,因此,两个阶段的刚度都很重要。本文对FRP增强钢筋混凝土梁在受拉纵筋屈服前和屈服后两个阶段的刚度进行了理论分析,将纵筋屈服前后截面弯矩表达为受拉纵筋和FRP应变的函数,推导了增强材料应变不均匀系数的计算式,通过全过程分析得到了受压区混凝土边缘平均应变综合系数随截面弯矩的变化规律,发现屈服后阶段的变化规律明显不同于普通钢筋混凝土梁;通过对80根试验梁数据和40根模拟梁的全过程分析数据进行回归,得到了FRP增强钢筋混凝土梁的刚度和挠度计算式;将计算值与本文试验的实测值以及全过程分析结果进行对比,最后用文献中的试验数据进行了验证。结果表明,本文提出的刚度和挠度计算式具有较高的精度。
It is important to concern both of the pre-and post-yield stages of FRP sheets strengthened RC beams,since the pre-yield stiffness of FRP（fiber reinforced polymer）sheets strengthened reinforced concrete beams is the stiffness of normal service phase while the post-yield stiffness is very effective on controlling the deformation of these beams.Calculating methods of both pre-yield stiffness and post-yield stiffness of these beams were analyzed in this paper.Bending moments before and after longitudinal reinforcement yielding were expressed as functions of tensile strain of longitudinal reinforcment and FRP reinforcement.The comprehensive coefficient of the variation of the average concrete strain at the upper edge of compression zone along with the bending moment was obtained by full-range analysis.The difference between these beams and the normal RC beams was also identified.Stiffness and deflection formulas of FRP sheets strengthened reinforced concrete beams were obtained by regression analysis of the data from 80 pieces of test beams and 40 pieces of full-range analysis beams.Prediction results were compared with the test results and the results from full-range analysis.The results were also verified according to the test results available in the literature.The results show that the proposed calculating formulas of stiffness and deformation are sufficiently accurate.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2011年第4期87-94,共8页
Journal of Building Structures
基金
"十一五"国家科技支撑计划项目(2006BAJ03B07)
国家自然科学基金项目(50908045)
国家自然科学基金项目(51078077)
关键词
FRP片材增强钢筋混凝土梁
全过程分析
刚度
挠度
二次刚度
FRP sheets strengthened reinforced concrete beam
full-range analysis
stiffness
deflection
post-yield stiffness
