EXPERIMENTAL INVESTIGATION ON RESIDUAL STRESS DISTRIBUTION AND RELAXATION EFFECT AT DOUBLE-SIDE WELDED RIB-TO-DECK JOINTS OF ORTHOTROPIC STEEL DECKS

Abstract

The welding residual stresses (WRS) will shorten the fatigue resistance of rib-to-deck (RTD) joints of orthotropic steel decks (OSDs) in bridge engineering. It is essential to obtain WRS and its distribution to accurately assess the fatigue damage of RTD joints in OSDs subjected to vehicle loads. Initial WRS will release under cyclic loading, resulting in the redistribution of WRS in steel bridges. To estimate the relaxation of initial transverse WRS, experimental investigations on WRS distribution in initial state and its relaxation law under cyclic loading were conducted of the double-side welded RTD joints using ultrasonic Non-destructive Testing. The results indicate that the initial transverse WRS at the heat affected zone of both inside and outside of decks vary from 0.50fy to 0.83fy, and transform within the range of 0.27fy~0.43fy at both inside and outside surfaces of U-ribs. WRS relaxation is prone to be activated under cyclic loading, especially at the first cycles. Afterwards, the WRS proceed with relaxation at a lower rate, remaining almost stable with more repetitions of loading.