Numerical study on girth weld of marine steel tubular piles

• The first detailed numerical study on the SCF at splice weld of marine steel pile subjected to both axial tension and bending moment.
• Formulation of a SCF formula considering both bending moment and axial tension.
• A detailed numerical study that essentially verifies the flat-plate solutions.
• Practical examples that covers typical pile configurations in marine applications.

At a splice weld of marine steel tubular pile, the misalignments between two adjacent pile segments may cause significant stress concentrations. In structural analysis, the stress concentrations shall be properly addressed, normally by a stress concentration factor (SCF) in practice. Based on a flat-plate configuration, the SCF at pipe splice under either axial tension or in-plane bending moment has been theoretically derived. To verify the effectiveness of the flat-plate solutions, this paper investigated the SCFs with numerical modeling. Finite element models built by ANSYS were used to simulate pipe splices for different pile diameters and wall thicknesses, which are representative of practical marine applications. Axial tension and in-plane bending moment, as well as their combination were applied. The flat-plate solutions were compared with the numerical results. The results show that the flat-plate solutions are close to the numerical results, indicating that they are reasonably effective in practical applications under complex loading conditions. The findings will significantly help in the hot-spot analysis for splice welds of steel tubular members, particularly piles, in marine structures given complex loading effects. Additionally, an integrated formula including the effect of both axial tension and in-plane bending moment is formulated for the SCF at pile splice.