任意截面无黏结预应力混凝土梁的有限元分析

建立了基于大变形非线性有限元理论的无黏结预应力混凝土梁的计算模型,能够较好地预测任意截面无黏结梁整个加载历史的非线性结构响应.无黏结筋的效应以等效节点荷载替代,由此可按普通有黏结钢筋混凝土梁进行分析,其截面内力由外荷载和无黏结筋等效节点荷载共同引起.利用修正的Rodriguez截面分析模型,混凝土的贡献通过边界顶点定义的梯形单元来实现.导出了任意截面无黏结预应力混凝土梁非线性全过程分析的标准有限元公式.无黏结试验梁的分析计算结果与试验结果吻合良好.

Finite element analysis of unbonded prestressed concrete beams with arbitrary sections

A computational model for unbonded prestressed concrete beams based on large deformation finite element theory was developed, which is capable of predicting the nonlinear structural response of the unbonded prestressed beams with arbitrary sections throughout the whole loading history. By replacing the effect of unbonded tendon with equivalent nodal loads, analysis can be performed with the ordinary bonded reinforced concrete beams, whose internal forces are caused by external loads and equivalent nodal loads from unbonded tendon together. The section analytical model suggested by Rodriguez was revised and utilized. The contribution of the concrete was expressed by the trapezoids defined by the vertices of boundaries. The standard finite element formulae for nonlinear full-range analysis of unbonded prestressed concrete beams with arbitrary sections were derived. The computational results of unbonded test beams agree well with the experimental ones.