For welded bridge components, the knowledge of residual stresses induced by welding is essential to determine their effect on the fatigue life behavior resulting in optimal fatigue design and a better knowledge about the fatigue strength of these welded connections. The residual stresses of a welded component in an orthotropic steel bridge deck are determined with the incremental hole-drilling method. This method is specified by the American Society for Testing and Materials ASTM E837-13a and it can be used only when the material behavior is linear-elastic. However in the region of the bored hole, there are relaxed plastic strains present that can lead to significant error of the measured stresses. The hole-drilling procedure is simulated with three-dimensional finite element modeling including a simplistic model of plasticity. The effect of plasticity on uniform in-depth residual stresses is determined and it is concluded that residual stresses obtained under the assumption of linear-elastic material behavior are an overestimation. Including plasticity for non-uniform in-depth residual stress fields results in larger tensile and smaller compressive residual stresses. Larger tensile residual stresses cause premature fatigue failure. Therefore, it is important to take these larger tensile residual stresses into account for the fatigue design of a welded component.

Complex welding operations in orthotropic steel bridge decks introduce residual stresses near the weld region. To estimate fatigue failure of this type of bridge deck, tensile residual yield stresses are usually assumed around the weld region. However, to estimate the residual stress distribution near a weld connection more precisely, a test setup is developed. The weld connection of a closed longitudinal trapezoidal stiffener with the deck plate of an orthotropic bridge deck is investigated. The incremental hole-drilling technique is used to measure the residual stresses with strain gauge rosettes. Strain gauge rosettes are positioned on the deck plate and on a longitudinal stiffener of the orthotropic steel deck. A small hole is drilled through the center of the strain gauge rosettes and strains are measured at incremental depths. The residual stresses are calculated and based on these experimental measurements a distribution of the residual stresses is obtained. Compressive residual stresses exist near the longitudinal stiffener-to-deck plate weld. On the deck plate, the compressive residual stresses are equal to 60% of the yield strength while the compressive residual stresses on the stiffener are 42% of the yield strength. There are tensile residual stresses on both sides of the weld region. However, more research is necessary to confirm this distribution since it is contradictory to expected stresses in literature.

A three-dimensional finite element welding simulation procedure is developed with the software Siemens NX and solver type SAMCEF in order to determine the residual stresses of a welded component of an orthotropic bridge deck. The welding process of a deck plate which is welded to a closed trapezoidal stiffener is simulated. A decoupled thermal-mechanical analysis is performed. During the thermal analysis, the temperatures introduced by the passage of the welding torch are calculated for different time steps. This temperature field is used during the thermal analysis to determine the residual welding stresses for the same time steps. The decoupled thermal-mechanical analysis gives the distribution of the residual stresses in the longitudinal direction. Only this direction is discussed since this is the direction that follows the welding path. On the deck plate there are tensile yield residual stresses near the weld region. In between the welded webs of the stiffener, there are compressive residual stresses. For the longitudinal stiffener, there are again tensile yield residual stresses near the weld which decrease at a greater distance and turn into compressive residual yield stresses. The finite element model results in a residual stress distribution introduced by the welding operation. This distribution can be used in future research to determine the effect of residual stresses on the fatigue life of this welded component in the orthotropic bridge deck.

This article performs a parameter study on a detailed finite element model of a simple arch bridge consisting of a single arch. The objective is to investigate the influence of different hanger arrangements, dimensions and finally a variation of the angle of skewness between the arch axis and longitudinal bridge deck axis. The influence on the stresses, forces and bending moments in the bridge deck girders, hangers and arch is examined. Finally, a buckling analysis is performed on all different models and the change in critical buckling load is discussed. The displacements in the bridge deck stay the same for small angles of skewness. Starting from an angle of ± 13°, the position of maximum deflection in the bridge deck shifts towards the ends of the bridge deck instead of being situated staying in the middle. This can be explained by the influence of the wind load acting on the arch structure and the direction of the horizontal resultants of the hanger forces. This can cause partial relaxation, thus ensuring a small uplift at the longitudinal girders of the bridge deck. This is also the cause for the higher displacements in the arch. The torsion effect in the arch results in a counter clockwise rotation of the arch. When performing a buckling analysis on the changing angle of skewness, it is found that this initially has only a small impact on the critical load factor.

Manufacturing processes such as welding operations cause residual stresses which are present in most civil structures. They create plastic deformations without any external loads and therefore are often overlooked during design. Nevertheless, residual stresses can have profound influences on the fatigue life. This is also true for orthotropic steel decks. Unfortunately, for these bridges, little is known about the real distribution of residual stresses due to welding. Therefore, a semi- destructive experimental test setup is developed: hole-drilling. It became clear that near the weld region, the overall conclusions confirm the widely assumed tensile yield stresses. Further away from the weld region, the residual stresses decrease to almost zero. In conclusion, with the hole- drilling technique, it is possible to achieve a clear pattern of the existing residual stresses near welded locations without really damaging the structure. This knowledge can highly improve future fatigue calculations.