预应力混凝土结构非线性有限元分析

提出了能反映预应力钢筋与混凝土间相对滑移和相互作用的单元模型,此模型可模拟预应力钢筋的张拉和用于无粘结预应力混凝土结构分析。采用这一单元模型建立了预应力混凝土结构的非线性分析有限元模型,非线性方面考虑了材料和几何非线性、预应力摩擦损失、钢筋松弛、混凝土收缩和徐变等因素。该有限元模型可用于有粘结和无粘结预应力混凝土结构张拉施工和工作阶段的全过程分析,分析内容包括弹塑性变形、混凝土开裂和破坏等。最后给出了有粘结和无粘结预应力混凝土连续梁的分析实例,受力变形、破坏形态等的分析结果与试验结果吻合良好,验证了该模型的合理性和有效性。

Nonlinear finite element analysis of prestressed concrete structures

A tendon model,which can represent the interaction between tendon and concrete of the prestressed concrete member,is proposed based on the finite element method.This model is capable of simulating the slip of tendon in concrete duct,so that it can deal with the prestressing transfer of post-tensioned structures and it can describe unbonded prestressed structures more efficiently,especially for multi-tendon cases.By using these models,a numerical procedure is established for material and geometric nonlinear analysis of prestressed concrete structures,including time-dependent effects due to load history,relaxation of prestress,and creep and shrinkage of concrete.The procedure can predict the responses of bonded or unbonded post-tensioned plane concrete structures throughout their prestressing transfer and service load history,such as elastic and plastic deformation,cracking and damage patterns.Numerical examples of post-tensioned bonded and unboned continuous beams are presented.The comparison of computed results,including loading-deformation,damage patterns etc.,with experimental ones shows good agreement,demonstrating the efficiency of the proposed model.