Fatigue Damage Analysis of Composite Girder with Steel Bottom Plate and Corrugated Steel Webs Under Uniform Corrosion

This study investigates the influence of uniform corrosion on the fatigue damage of the composite girder with steel bottom plate and corrugated steel webs. An uncorroded composite box specimen and a salt-corroded (uniform corrosion) composite box specimen were designed and prepared for the fatigue and static tests, both fabricated at a scalc of 1: 8. 82. The test phenomena, stress development and damage conditions were compared with the theoretical analysis results. It is concludcd that the salt-corroded composite girder is with obvious corrosion in the steel bottom plate, which should be given great concern. The fatigue damages of the uncorroded girder and the salt-corroded girder are similar, all are the fatigue damages at the welding points in the interface of the midspan steel bottom plate and the webs, indicating that uniform corrosion will not influence the welded joints at the steel-concrete interface and become the source of damages. The salt-corroded girder reveals greater Stresses in the steel bottom plate than those in the uncorroded girder, suggesting that uniform corrosion cnlarges the fatigue damages of the girder under the same level of loads and accelerates the oecurrence of fatigue damages. Whcn the corrosion rate is below 20%, the fatigue damage of the salt-corroded girder grows exponentially as the corrosion rate increases, and the greater the corrosion rate, the morc significant the fatigue damage would be. © 2025 Wuhan Bridge Media Co., Ltd., MBEC. All rights reserved.