（华侨大学土木工程学院，泉州 362021）

［摘要］提出了普遍适用的无粘结筋应力增量的计算方法,用等效荷载来表示无粘结筋的作用，既满足纵向变形协调条件又满足梁截面弯矩-轴力-曲率关系。计算了对称和不对称加载的无粘结预应力连续梁的应力增量。计算表明对称加载的应力增量与回归公式的计算值吻合良好；不对称加载的应力增量低于相应的对称加载值，两者的比值近似等于两种加载产生的线弹性变形的比值，约为0.55～0.75。

［关键词］预应力混凝土；无粘结筋；非线性分析；极限应力；加载模式

Influence of asymmetric loading on ultimate stress of unbonded prestressed tendon

Fang Deping, Wang Quanfeng

(College of Civil Engineering, Huaqiao University, Quanzhou 362021, China)

Abstract:A generally applicable method to calculate stress increment of unbonded prestressed tendon is presented. The action of unbonded prestressed tendon is expressed by its equivalent loads. The method meets both longitudinal deformation compatibility condition and M-N-Φrelationship of beam section. The stress increments of unbonded prestressed tendon in the continuous beams subjected to both symmetrical and asymmetrical loads are analyzed. The increments for symmetrical loads conform well to results of the regression formula. The increment for asymmetrical loads is less than corresponding increment for symmetrical loads. The ratio of two increments is approximately equal to the ratio of the linear elastic deformations due to both loads, between 0.55～0.75.

Keywords:prestressed concrete; unbonded tendon; nonlinear analysis; ultimate stress; load mode

*福建省自然科学基金资助项目(E0410023，E0540005)；厦门市科技计划项目(3502Z20074039)。

作者简介：方德平，教授，博士，Email:fdp@hqu.edu.cn。