Validity of the approximate equation for predicting compressive stress in the posttensioned anchorage zone presented in the\nAASHTO LRFD Bridge Design Specifications was investigated in this study. Numerical analysis based on the finite element\nmethod (FEM) and theoretical analysis showed that the AASHTO formula gives relatively accurate stress values when the effect of\nduct holes is neglected. However, it was found that the formula can significantly overestimate the stresses in the actual prestressed\nconcrete member with spaces occupied by ducts. Therefore, an improved equation was proposed for the existing AASHTO\nequation to consider the effect of the duct holes on the stress distribution. This resulted in relatively accurate prediction of the\ndistribution and magnitude of the compressive stresses even with the presence of the duct holes. The proposed equation was also\nvalidated by comparing with the stresses measured in the test of a posttensioned full-scale specimen. This study is expected to\ncontribute to the design of the anchorage zone in prestressed concrete structures by suggesting a more reasonable way to assess the\nappropriateness of anchorage devices.
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