Experimental evaluation of stress concentration factor of welded steel bridge T-joints

This paper describes an experimental study on determining the stress concentration factor (SCF) and its stochastic characteristics for a typical welded steel bridge T-joint. A full-scale segment model, which holds the same profile with a railway beam section of the suspension Tsing Ma Bridge (TMB) in geometric dimension and material property as well as in weld details, is fabricated and tested. With the measurement data obtained from strain gauges deployed on the web and flanges, the hot spot strain at the weld toe is determined by a linear regression method. The SCF is then calculated as the ratio between the hot spot strain and the nominal strain which is obtained directly by measurement. To fully account for the effect of predominant factors on the scatter of SCF, the experiments are carried out under different moving load conditions. The statistical properties and probability distribution of SCF are derived, which reveals that the SCF for the welded steel bridge T-joint conforms to a normal distribution.

► Full-scale model experiments of a welded steel bridge T-joint are conducted.
► Stress concentration factor (SCF) and its stochastic characteristics are obtained.
► The SCF at the welded T-joint conforms statistically to a normal distribution.
► The stochastic SCF is suited for HSS-based fatigue reliability assessment.