【摘要】 GB50010、JGJ92和ACI318等国内外设计规范关于无粘结筋应力增量的计算和弯矩调幅设计都是针对单向受力梁板提出的,四边支承预应力混凝土双向板中无粘结筋应力增量的计算及这类板的弯矩调幅计算尚属空白.针对这一问题,采用ABAQUS大型有限元软件建立了无粘结预应力混凝土四边支承双向板有限元分析模型.考察了非预应力筋屈服强度和综合配筋指标对无粘结筋应力增量以及支座控制截面弯矩调幅系数的影响规律.分析结果表明:在正常使用阶段无粘结筋应力增量随综合配筋指标增大而增大,随非预应力筋屈服强度的提高而增大;在承载能力极限状态无粘结筋应力增量随综合配筋指标增大而减小,随非预应力筋屈服强度的提高而增大;弯矩调幅系数随综合配筋指标增大而减小,随非预应力筋屈服强度提高而减小.建立了无粘结筋应力增量及弯矩调幅系数计算公式,为四边支承无粘结预应力混凝土双向板设计计算提供依据.更多还原

【Abstract】 Design method of stress increment in unbonded tendons and moment redistribution in codes as GB50010、JGJ92 and ACI318 were mainly applied to linear members. The investigation of stress increment in unbonded tendons and the inner force redistribution of prestressed concrete edge-supported two-way slabs is few. Therefore,the finite element was modeled by ABAQUS soft-ware for unbonded prestressed concrete edgesupported two-way slabs, and the stress increment in unbonded tendons and moment redistribution of prestressed concrete edge-supported two-way slabs were studied,which were influenced by the grade of nonprestressing reinforcement and combined reinforcement index in critical section of support. It is shown that at serviceability state the stress increment in tendons increases with the higher combined reinforcement index and higher yield strength of non-prestressing reinforcements. At ultimate limit state the stress increment in tendons increases with the lower combined reinforcement index and higher yield strength of non-prestressing reinforcements. The moment redistribution coefficient reduces with the higher combined reinforcement index and higher yield strength of non-prestressing reinforcements. Calculation formulas of stress increment in tendons and moment redistribution coefficient in critical section of support are proposed,which provides basis for design of unbonded prestressed concrete edge-supported two-way slabs.更多还原