Abstract
Fatigue cracks at runways of steel track girders for a straddle type monorail have been studied experimentally and analytically. Full-scale fatigue tests of runways showed that repeated plate-bending stresses caused fatigue cracks at single-bevel groove-welded T-ioints between top flange and web and also at fillet welds connecting the longitudinal rib to the top flange. For fatigue lives over ten million cycles, fatigue strengths of single-bevel groove-welded T-joints under out-of-plane bending were obtained using small specimens. Equations for plate-bending stresses were given by a parametric study by F. E. M. Minimum thicknesses required for the top flange to prevent cracking were proposed.
