The research described in this report is the result of continued experimental studies performed in the laboratory under NCHRP Project 12-15(5). It is intended to provide additional information on the effects of infrequently exceeding the constant amplitude fatigue limit during the service life of bridge structures. Welded details simulating attachments used on steel bridge members were subjected to variable amplitude loading similar to the skewed spectra that most bridge structure experience. Only a few stress cycles exceeded the constant amplitude fatigue limit for a number of the welded details that were tested. The results obtained from the variable amplitude tests were found to supplement and further verify the observations reported in NCHRP Report 267.
Samenvatting