无黏结部分预应力砼梁恢复力模型的研究

基于OpenSEES软件的二次开发平台,对无黏结部分预应力混凝土梁的截面恢复力模型进行了研究.根据试验统计和理论分析,建立了无黏结部分预应力混凝土梁的截面弯矩-曲率滞回模型,并通过编制Visual C++程序,将其植入到OpenSEES软件的材料子类中,用于无黏结部分预应力混凝土结构的非线性计算,分析过程中无需迭代计算无黏结预应力筋的应力增量,解决了无黏结部分预应力混凝土结构受力分析的关键问题.利用OpenSEES软件,基于已建立的无黏结部分预应力混凝土梁的截面恢复力模型,选用基于柔度法的非线性梁柱单元,采用位移控制,计算了低周反复荷载作用下无黏结部分预应力混凝土梁的弯矩-挠度滞回曲线,计算曲线与试验曲线吻合良好,说明已建立的无黏结部分预应力混凝土梁的截面恢复力模型的可靠性,为无黏结部分预应力混凝土结构的非线性计算提供了理论依据.

Research on Restoring Force Model of Unbonded Partially Prestressed Concrete Beams

Based on the secondary development platform of OpenSEES software, this paper studied the restoring force model of unbonded partially prestressed concrete beam sections. According to the statistics of experiments and theoretical analysis, the moment-curvature hysteretic model of the section for unbonded partially prestressed concrete beams was established, and planted into Material class in the software of OpenSEES by compiling Visual C++ programs, which is used for the nonlinear analysis of unbonded partially prestressed concrete structure without iterative calculation of stress increment for unbonded prestressed tendon. The crucial problem of stress analysis for unbonded partially prestressed concrete structure was then solved. Moreover, under displacement control, this paper considered the nonlinear beam-column element based on flexibility to calculate the moment-deflection hysteretic curves of unbonded partially prestressed concrete beams under low cyclic reversed loading on the basis of established restoring force model. The calculation results are reasonably identical to experiment results, which indicates the reliability of established restoring force model, and provides theoretical basis for the nonlinear analysis of unbonded partially prestressed concrete structures.