CFRP加固混凝土墩柱温度自应力及参数研究

Study on Temperature Self-restrained Stress and Parameters of the Concrete Pier Column Strengthened by CFRP

基于平截面假定,考虑碳纤维布(CFRP)与混凝土的热膨胀系数不同,根据自平衡力系条件建立CFRP加固任意形状横截面混凝土构件因日照辐射或年温差引起的温度自约束变形求解方程。进而推导出CFRP加固混凝土矩形、箱形墩柱在指数温度梯度下和均匀温度梯度下的温度自应力解析式,并结合混凝土板壁式柔性墩算例分析,表明CFRP中将产生可观的温度自应力,在CFRP加固混凝土构件设计时应予考虑。最后讨论了CFRP的厚度、热膨胀系数、弹性模量和混凝土强度等级(弹性模量)、截面宽度、高度等参数对CFRP加固混凝土矩形墩柱温度自应力的影响,其结论对CFRP加固混凝土构件的受力分析及加固设计有一定的参考价值。

On the based of the assumption of the plane cross-section and the condition of the self equilibrating force system,and in consideration of the difference of thermal expansion coefficients between CFRP and concrete, the equation of temperature self-restrained deformation due to solar radiation or year temperature differences is established for the CFRP-strengthened concrete members with arbitrary cross-sections. The analytic formula of temperature self-restrained stresses is derived for rectangular-section and box-section concrete piers under two temperature gradient modes,the uniform distribution and the exponent distribution. Through analysis of a calculation example of a concrete flexible pier, it is seen that considerable temperature self-restrained stresses are generated in CFRP strengthening and so temperature self-restrained stresses should be considered in the CFRP-strengthening design of concrete members. The parameters affecting the temperature self-restrained stress of concrete rectangular pier columns strengthened by CFRP are discussed, such as the CFRP thickness, thermal expansion coefficient, elastic modulus, concrete grade（elastic modulus of concrete）, cross section width and height. Conclusions from the CFRP parameters study is useful to mechanical analysis and design of concrete members strengthened by CFRP.