柱支承无粘结预应力混凝土双向板内力重分布

为了研究柱支承预应力混凝土双向板中无粘结筋应力增长规律及弯矩调幅设计方法，采用ABAQUS大型有限元软件建立了柱支承无粘结预应力混凝土双向板的有限元分析模型。通过将双向板划分为柱上板带和跨中板带，分别考察了综合配筋指标和非预应力筋屈服强度对无粘结筋应力增量及支座控制截面弯矩调幅系数的影响规律。分析结果表明：在综合配筋指标和预应力度一定的条件下，正常使用阶段和承载能力极限状态无粘结筋应力增量随非预应力筋屈服强度的提高而增大，而支座控制截面的弯矩调幅系数随非预应力筋屈服强度的提高而减小。建立了以综合配筋指标和非预应力筋屈服强度为自变量的柱支承预应力混凝土双向板中无粘结筋应力增量和弯矩调幅系数计算公式。

Internal force redistribution of unbonded prestressed concrete flat plates

To explore the rule of stress increment in unbonded tendons and design method of moment redistribution, the finite element was modeled by ABAQUS soft-ware for unbonded prestressed concrete flat plates. The plates were divided into the column strips and the middle ones. Stress increment in tendons and moment redistribution coefficient of unbonded prestressed concrete flat plates were studied, which are influenced by the combined reinforcement index and grade of non-prestressing reinforcement. It is shown that the stress increment in tendons increases at the serviceability and ultimate limit states and moment redistribution coefficient in critical section of support reduces with the higher yield strength of non-prestressing reinforcements in flat plates. Then expressions of stress increment in tendons and moment redistribution coefficient in prestressed concrete flat plates were developed, in which the combined reinforcement index and grade of non-prestressing reinforcement were considered.