预应力框架中无粘结筋应力增量的弹性分析

Elastic Analysis of the Stress Increment of Unbonded Tendon in Prestressed Concrete Frame

提出弹性状态下精确分析无粘结筋应力增量的方法，导出考虑整根梁变形状态的无粘结筋变形计算公式并编制相应的计算程序，用迭代逼近法求解框架中无粘结筋的应力增量．计算结果表明：无粘结筋应力增量显著低于控制截面相应的有粘结筋，它为跨中有粘结筋的４０％～６０％．

For accurately analysing the stress increment of unbonded tendon under elastic state,a method is proposed. A formula is derived for calculating the deformation of unbonded tendon,With the deformation of the whole beam being taken into consideration.The corresponding computer program is developed;and the stress increment of unbonded tendon in the frame is calculated by iterative approximation.As shown by calculated effects,the stress increment of unbonded tendon is markedly lower than the counterpart of bonded one at control section,with a value about 40-60% of the bonded one at mid-span section.