Multiaxial fatigue criteria for prestressed strengthening of steel connections

In this study, the high-cycle fatigue behavior of bridge connections subjected to distortion-induced loadings (generating multiaxial stresses) and strengthened with prestressed elements were experimentally investigated. Thereafter, appropriate critical plane-based multiaxial fatigue thresholds based on the modified Wohler curve method (MWCM) and Fatemi-Socie's (FS) criteria were used to predict the initiation of cracks in the angles considering the estimated fully reversed uniaxial and shear fatigue limits as well as residual stresses. The prestressed strengthening system was effective in reducing the mean values as a result of the prestressing force, enabling a shift in the stress state to below the initiation threshold.

Automated summary

This study experimentally investigated the high-cycle fatigue behavior of bridge connections under distortion-induced loadings and prestressed strengthening. Critical plane-based multiaxial fatigue thresholds were appropriately used to predict crack initiation, considering fully reversed uniaxial and shear fatigue limits as well as residual stresses. The prestressed strengthening system effectively reduced stress mean values, shifting the stress state below the initiation threshold.