Fatigue behavior of RD joint in OSBD subjected to local corrosion at top plate

Abstract

Corrosion accelerates the propagation of fatigue damage and significantly reduces the fatigue life of the orthotropic steel bridge deck (OSBD). This paper experimentally investigates the effects of local corrosion on the fatigue behavior of rib-to-deck (RD) joints in OSBDs. Firstly, an accelerated corrosion test was conducted to obtain corrosive effects for various corroded RD joint specimens. Next, the 3D scanning technology was used to test the geometric characteristics of corrosion regions. Then, the strain, failure mode, crack growth, and fatigue performance of corroded RD joints subjected to various fatigue cycles are discussed based on the fatigue loading test. Finally, a three-dimensional solid model of RD joint was established utilizing ABAQUS-FRANC3D (F-A) technology to analyze fatigue crack stress intensity factors (SIFs). The results indicated that corrosion has the greatest impact on the strain of the top plate weld toe, followed by the top plate weld root, with the least impact on the U-rib weld toe. The crack initiation life of specimens with a corrosion rate of 10.81%, 20.47%, and 30.14% decreased by 24.24%, 30.30%, and 60.61%, respectively, and the crack propagation life decreased by 2.11%, 21.05%, and 78.95%, respectively. The fatigue crack propagation of locally corroded RD joint is jointly controlled by type I, II, and III SIFs, and belongs to a composite fatigue crack dominated by type I cracking. The SIF at the welding toe of the top plate during U-rib bottom plate corrosion is greater than that of the top plate corrosion. The effects of the initial crack shape ratio and deflection angle on the SIF increase as the corrosion rate increases.