针对偏心受压配筋构件徐变计算较为繁琐的现状,提出一种考虑钢筋作用的混凝土徐变应变实用计算方法。通过定义钢筋有效面积来反映构件配筋对徐变的影响,并根据弯矩等效的原则建立钢筋实际面积与有效面积的换算关系。根据各层钢筋在截面应力形心处的等效面积(有效面积)获得截面的有效配筋率,进而可参照轴心受压构件徐变应变计算过程中对钢筋作用的处理方式,计算截面的徐变应变。算例表明,该方法的计算精度与老化系数法相当。由于避免了繁琐的净截面特性计算过程和方程组建立、求解过程,在使用上更为方便,可用于偏心受压构件,尤其是多层配筋的偏心受压构件的徐变计算。
A creep analysis method for reinforced concrete members under eccentric compression is presented as considering the effect of steel reinforcements on creep.Effective area is defined to quantify the effect of steel reinforcement on creep.The relationship between the effective area and the actual area of steel reinforcement is obtained by the principle of bend moment equivalent.The effective reinforcement ratio is derived.With this ratio,the creep stress of reinforced concrete members under eccentric compression can be calculated like those under axial compression.Numerical examples are given to illustrate the application of the proposed approach.It is shown,through the examples,that the proposed method is well-matched in the accuracy with the method which makes use of the aging coefficient.Avoiding calculating the characteristic of the net concrete section and solving the algebraic equations,the proposed method is convenient in use.It is suitable for the creep analysis of reinforced concrete members under eccentric compression,especially for the members with multi-layers of steel reinforcements.