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利用通用商业有限元软件ABAQUS提供的用户子程序UMAT,采用Fortran语言编程对ABAQUS进行二次开发,将反映混凝土徐变性能的本构方程引入ABAQUS,从而实现预应力混凝土梁长期性能的有限元分析计算,并已得到已有试验结果验证。总结了预应力混凝土梁长期性能的关键影响因素,并对多根试件进行设计和参数分析,重点考察跨中截面上下缘应力差、混凝土等级、预应力筋初始有效应力大小、预应力筋种类和面积、普通钢筋配筋率等对其长期性能的影响规律。在此基础上,提出了考虑多因素影响的预应力混凝土梁长期变形简化计算公式。基于已有研究者的实验室试验与现场试验结果,对本文计算公式及国内外规范的计算公式进行了验证与对比,结果表明:本文公式计算值与试验结果的平均误差在10%以内。
The user subroutine UMAT provided by commercial finite element software ABAQUS was used to develop ABAQUS by Fortran language programming. The constitutive equation reflecting the creep property of concrete was introduced into ABAQUS so as to realize the finite element analysis of long-term performance of prestressed concrete beams. Calculated, and has been verified by the test results. The key factors that affect the long-term performance of prestressed concrete beams are summarized, and the design and parameter analysis of multiple specimens are conducted. The stress difference between the upper and lower edges of the mid-section, the concrete grade, the initial effective stress of prestressed tendons, And area, the rate of reinforcement of ordinary steel on its long-term performance of the law. On this basis, the simplified formula for long-term deformation of prestressed concrete beams considering multi-factors is proposed. Based on the existing laboratory experiments and field tests, the calculation formula of this paper and the calculation formula of domestic and foreign norms are verified and compared. The results show that the average error between calculated value and test results in this paper is within 10%.