预应力CFRP加固钢筋混凝土受弯构件的抗力概率模型研究

预应力CFRP 加固混凝土结构技术因其在材料性能利用方面的优越性能已成为CFRP 加固的热点方向,其中预应力CFRP 加固结构的可靠性是这一方向研究的重要内容。该文分析了影响预应力CFRP 板加固钢筋混凝土受弯构件承载力的主要变量的概率特征,考虑CFRP 板尺寸效应和应力分布的影响,采用Weibull 分布推导了CFRP 板的极限强度概率分布函数,根据预应力CFRP 张拉工艺,分析了预应力损失随机变量,建立了在不同失效模式(破坏形态)下的受弯构件抗力概率模型,并开展了参数敏感性分析,获得各个失效模式下抗力概率模型的主要影响因素。研究结果表明:抗力概率模型是预应力CFRP 加固结构的失效概率计算与可靠度校准的重要内容之一,各参数的影响规律与各失效模式的破坏形式密切相关。

PROBABILITY MODEL OF THE FLEXURAL RESISTANCE OF REINFORCED CONCRETE BEAMS STRENGTHENED WITH PRESTRESSED CFRP PLATES

The technique of strengthening concrete structure using prestressed CFRP is one of prime focuses of the strengthening structure with FRP in recent years due to its ability of efficiently utilization of material strength,of which the reliability of the structure strengthened with prestressed CFRP laminate is a key issue.In this paper the statistical character of design variables of reinforced concrete beams strengthened with prestressed CFRP plates is assessed.Accounting for size and stress gradient effects,Weibull distribution is used to describe the probability distribution function.The loss of prestressed loads is analyzed considering the prestressing method.The probability models of the flexural capacity are established for the three failure models,and the influence of variables on the flexural capacity is also studied.The probability model derived in this paper can be used as the theoretical basis of the reliability analysis and safety assessment of the strengthened structure.