一、挠曲变形的三个阶段梁的挠曲变形可分为三个阶段,兹简述如下: 第一阶段,可称为裂前阶段,此时构件尚无裂缝发生; 第二阶段,可称为开裂阶段,构件上有裂缝发生,但其宽度及分布情况均在可接受的范围内; 第三阶段,可称为变形后期阶段,此时纵筋已屈服,变形及裂缝开展均较大。各阶段的变形特性以及ACI规范对于刚度的计算方法亦各不相同。 First, the flexural deformation of the beams in the three stages of deflection can be divided into three stages, which are briefly described as follows: The first stage, which can be called the precrack stage, at this time there is no crack in the component; in the second stage, In the cracking stage, there are cracks on the component, but its width and distribution are within the acceptable range. In the third stage, it can be called the later stage of deformation. At this time, the longitudinal bar has yielded, and the deformation and crack development are large. . The deformation characteristics at various stages and the ACI specifications also differ in how the stiffness is calculated.