Experimental Investigation of Fatigue in Steel Beams under Cyclic Bending Loading

Abstract

This research aims to investigate the fatigue behavior of structural steel beams, focusing on fatigue-induced damage, mechanical properties, repair strategies, and fatigue life. The study examines steel beams in three conditions: beams without pre-cracked notches, beams with pre-cracked notches, and beams with stop-hole installed at the tips of the pre-cracked notches. The fatigue tests were conducted until the specimens lost their load-carrying capacity or reached their fatigue life limits based on predefined criteria. The test results indicate that the fatigue life of undamaged steel beams is comparable to the values specified in the AASHTO standard. In contrast, steel beams with pre-cracked notches exhibit a shorter fatigue life due to the notch serving as an initiation point for crack propagation. However, beams with stop-hole at the tips of the pre-cracked notches demonstrated a longer fatigue life than those with pre-cracked notches alone, as the stop-hole help to redistribute and reduce stress concentration at the notch tips. The findings of this study provide valuable insights for assessing the fatigue life of damaged steel beams and applying stop-hole as an effective measure to slow crack growth. This information is crucial for planning repairs and extending the service life of steel structures efficiently.