后张法预应力筋张拉时沿其长度方向的应力变化,可假定为如图1所示的ABC曲线。图中EDBC曲线表示预应力筋张拉与锚固后所假定的应力变化。应当注意,预应力筋端部由于锚固过程引起的应力损失。当张拉力从千斤顶传递到锚固装置时应力就有损失,此时预应力筋的张拉伸长值由于锚具变形而部分回缩。虽然,有些支承式锚具(如镦 The post-tensioned prestressed tendons can be assumed to have an ABC curve as shown in FIG. The EDBC curve in the figure represents the assumed stress change after tensioning and anchoring of prestressed tendons. It should be noted that the stress loss due to the anchoring process occurs at the ends of the pre-stressed tendons. When the tensile force is transferred from the jack to the anchoring device, the stress is lost. At this time, the tensile elongation of the prestressed tendon is partially retracted due to deformation of the anchoring device. Although some support anchors (such as