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建立了基于增量变形的适用于无粘结预应力混凝土梁受力全过程的数值分析方法,可用来分析正常使用状态及承载能力极限状态下,无粘结预应力筋应力的变化情况。本文的方法能够模拟混凝土梁开裂引起的结构刚度变化情况,利用本文所建立的分析方法,研究了不同加载方式、跨高比、预应力筋线形对无粘结预应力筋应力增量的影响。与现有理论计算方法及试验结论的对比结果表明基于增量变形的数值方法略大于理论计算结果,并准确反映了无粘结预应力筋的应力增量与关键截面变形值接近直线关系这一结构机理,说明利用基于增量变形的数值方法可对无粘结预应力筋的应力变化、无粘结预应力混凝土梁的抗弯强度进行较合理而精确的评估。
A numerical analysis method based on incremental deformation for the whole process of unbonded prestressed concrete beams is established, which can be used to analyze the stress changes of unbonded prestressed tendons under normal use and ultimate load carrying capacity. The proposed method can simulate the change of structural stiffness caused by cracking of concrete beams. By using the analysis method established in this paper, the influence of different loading methods, span ratio and prestressing tendon shape on the stress increment of unbonded tendons is studied. Compared with the existing theoretical calculation and experimental results, the numerical method based on incremental deformation is slightly larger than the theoretical calculation and accurately reflects the close linear relationship between the stress increment of unbonded prestressed tendons and the critical cross-section deformation The results show that the stress of unbonded prestressed tendons and the flexural strength of unbonded prestressed concrete beams can be estimated more reasonably and accurately by using the numerical method based on incremental deformation.