Analyses of Post-Tensioned Girder Anchorage Zones

Several large thin-webbed box girders, with post-tensioned anchorage zones designed in accordance with AASHTO and ACI requirements, have experienced large cracks along the tendon path in the anchorage zones at the design stressing load. Cracking of this nature provides a path for penetration of moisture and salts and thus presents a potential corrosion and frost damage threat. In addition, such cracking negates a major reason for the use of prestressed concrete, the minimization of service load cracking.

This report summarizes an extensive literature review which documents the state-of-the-art in anchorage zone analysis, behavior, and design recommendations. In addition, the report outlines the general utilization of a powerful three-dimensional finite element prgram--PUZGAP-3D--for analysis of the complex anchorage zone region. The program was used to study both straight and curved tendon paths. Good correlation was found with experimental results up to first cracking which indicated that the program was very useful for exploring the effects of various parameters.