预应力扁梁-密肋楼盖体系的受力分析

预应力扁梁-密肋楼盖体系是一种适合于中等跨度以上柱网的楼盖体系,该体系空间作用较强,受力复杂,因此出于结构安全性和适用性要求的考虑,研究该楼盖体系中建立的预应力效应就显得十分必要.针对某实际工程中无粘结预应力扁梁-密肋楼盖体系的预应力张拉过程,现场量测了楼板和预应力混凝土梁的变形和应变,运用有限元程序进行了模拟分析,分析模型考虑了预应力的瞬时损失以及模板支撑的作用,并与现场实测数据进行了比较,讨论了该结构体系中预应力效应的建立情况,指出梁中预应力效应的建立较大程度地受到楼板平面内刚度的影响.在有限元三维实体模型分析的基础上,对楼板平面内刚度的影响进行了进一步的探讨,提出了该体系中梁的预应力效应的简化计算方法.

Analysis of prestressed concrete flat beam-waffle slab system

The prestressed flat beam-waffle slab system is fit for the structures with more than middling spans.The dimensional effect in the structural system is strong and the mechanical performance is complicated.Because of the requirement for safety and applicability,it is quite necessary to study the prestressing efficiency in the slab system.During the prestressing of a unbonded prestressed concrete wide flat beam-waffle slab system in practice,the displacements and strains of slab and the prestressed concrete beam were site-measured and the results were analyzed.The prestressing construction was simulated by finite element program.The effects of prestress loss and forming were taken into account in the analytical model.Comparison was made between the results calculated and the ones measured.The prestressing efficiency of the unbonded prestressed concrete wide flat beam-waffle slab system was discussed,indicating that the prestressing efficiency was greatly affected by the in-plane stiffness of slab.Based on the three-dimensional finite element analysis of solid model,the effect of the inplane stiffness of slab was discussed in detail.A simplified method was presented to calculate the prestressing efficiency of prestressed beams in that system.