FATIGUE BEHAVIOR OF VARIABLE LOADED BRIDGE DETAILS NEAR THE FATIGUE LIMIT.

The findings of the current NCHRP Project 12-15(5), Fatigue Behavior of Variable Loaded Details Near the Fatigue Limit, are highlighted. The main focus of the research is the examination of welding bridge details in the high-cycle, long-life regime. Large-scale plate girders with coverplate, web attachment, and web stiffener details are subjected to fatigue loading that simulates actual truck traffic. A Rayleigh type stress spectrum is used with the inclusion of an occasional overload exceeding the constant-amplitude fatigue limit. The frequencies of occurrence being considered for the overloads are 0. 1, 0. 05, and 0. 01 percent. The current test specimens also allow for a detailed study of distortion-induced fatigue cracking at a connection plate web gap detail. Results indicate that the retrofit method of drilled holes at the crack tip is inadequate at high levels of distortion.

FATIGUE BEHAVIOR OF VARIABLE LOADED BRIDGE DETAILS NEAR THE FATIGUE LIMIT. Academic Article