Determining the SCFs of tubular bridge joints with an alternative method

• Welded tubular bridge joints are prone to fatigue damage.
• The hot spot stress method with simplified extrapolation zone is recommended.
• An alternative method to calculate the SCFs of complex bridge joints is proposed.
• The SCFs are made independent of the boundary conditions with a wireframe model.
• The alternative method is applicable to any joint and determines accurately all SCFs.

Circular hollow sections are being used in various modern bridges. Although these bridges are highly appreciated because of their aesthetic value, they are considered to be costly, mainly due to the use of cast or welded joints. The fatigue strength of these structures is important since stress concentrations are reached near the weld toe of the joints. These are due to geometric discontinuity and to the welding process, thus making this type of bridge prone to fatigue damage caused by varying traffic loads.There are various methods to determine the stress concentration factors (SCFs) of a welded tubular joint. The existing methods are not suitable for complex tubular joints or require vast computing time. An alternative method for determining the SCFs of complex tubular bridge joints is being proposed. This method is applicable to any tubular joint and accurately determines all SCFs of the joint. These SCFs allow fast computation of the hot spot stresses of the tubular joint loaded with any realistic load condition.