Stress relaxation of stainless steel rods for bridge pier cap shear strengthening
Krapf, Carlyn Nicole
MetadataShow full item record
This thesis examines the stress relaxation phenomenon that may occur in stainless steel rods that are used as part of an all-stainless steel externally post-tensioned rod system for strengthening reinforced concrete pier caps in shear. An overview of the stress relaxation phenomenon and its modeling is presented. Previous work on stress relaxation of stainless steel is reviewed and used to select an appropriate stress relaxation model to analyze the stress relaxation data obtained from experiments performed during this research. An experimental program utilizing six specimens of Type 304/304L stainless steel stainless steel rods similar to those likely to be candidates for pier cap rehabilitation is presented, and the data are analyzed using the model identified from the review. This model reasonably captures the behavior of the resulting stress relaxation with time, and calculates stress values that are fairly close to those obtained experimentally. Using this model to predict long-term stress losses in a service environment, guidelines for design and installation of the post-tensioned stainless steel rods are proposed.