混凝土梁板中无粘结筋应力增长规律

Laws of stress increment in unbonded tendons in concrete beams and slabs at serviceability stage

针对无粘结预应力混凝土梁板在受荷过程中无粘结筋不符合变形平截面假定的特点,应用等刚度法编制了可用于考察正常使用极限状态无粘结筋应力增长规律的计算程序.基于模型试验结果和仿真分析结果,得到了非预应力筋配筋指标βs、预应力筋配筋指标βp、跨高比l/h、加载形式、预应力筋布筋型式、预应力筋合力点至受压区边缘距离hp等参数对正常使用阶段极限状态下简支、连续梁板中无粘结筋应力增长的影响规律;并建立了使用阶段无粘结筋应力增量计算公式.

Considering that the plane -section assumption can not be applied to tendons＇ strain in unbonded prestressed concrete beams and slabs subjected to loading calculation programs for the laws of stress increment in , the equivalent stiffness method was used to compile unbonded tendons at serviceability limit state. Based on resuhs of model test and simulation analysis, laws of the influence of some basic factors such as the non - prestressed reinforcement indexβn, the prestressed reinforcement indexβ p, the ratio of span to depth l/h, the loading type, the distribution of prestressed reinforcements and the depth h pfrom concrete extreme fiber to centroid of the prestressing steels, on the stress increment of unbonded tendons in simple and continuous beams and slabs were obtained. And then calculation formulas of stress increment in tendons during the serviceability stage were established.