锚具变形、钢筋回缩和接缝压缩引起的预应力损失数值模拟与试验研究

Numerical Simulation and Test Study of the Stress Loss Resulting from the Deformation of the Anchoring Device,the Contraction of Reinforcing Steel Bars and the Compressure of the Juncture

先张法和后张法预应力混凝土构件预应力损失均含有锚具变形、钢筋回缩和接缝压缩损失,该项预应力损失是张拉锚固阶段主要预应力损失。利用《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTGD62-2004)中计算锚具变形、钢筋回缩和接缝压缩损失方法和ANSYS有限元分析软件中单元特点,提出了一种在有限元中模拟该项预应力损失的方法,并推导了该项预应力损失的数值计算公式。通过有限元模型的分析现场试验表明:两者结果吻合较好;可以在有限元模型中模拟锚具变形、钢筋回缩和接缝压缩损失,误差均在3%以内。

The stress loss of both pre-tensioned and post-tensioned pre-stressed concrete members results from the deformation of anchorage devices, the contraction of reinforcing steels and the compression of junctures and the stress loss represents the major stress loss at both the tensioning anchoring stages. In the light of the methods for the calculation of the stress loss resulting from the deformation of anchoring devices, the contraction of reinforcing steel bars and the compressure of junctures prescribed in 《Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridge and Culverts》（JTGD62-2004） specification and the characteristics of the single element in the finite element analysis software,a new method to simulate the loss of the pre-stressing stress is provided by means of the ANSYS in the paper, with the numerical formulae for calculating the loss of the prestressing stress deduced. The result of the finite element analysis and that of the site tests are found to be in good agreement with each other,according to which it may well be concluded that the finite element model can be used to accurately simulate the loss of the stress resulting from the deformation of anchoring devices, the contraction of reinforcing bars,the compressure of junctures, with an error less than 3 %.