Fatigue assessment in steel railway bridges using output only vibration measurements and partial structural information

Abstract

A novel methodological framework for the online fatigue lifetime assessment of steel railway bridges is presented in this paper. By adopting a simply supported beam model amenable to a moving force at a constant velocity, the framework presumes the availability of noise-corrupted structural vibration acceleration response measurements and formulates an online estimator that identifies the unknown (i) excitation force, (ii) structural information, which herein pertains to the modal damping ratio, and (iii) modal displacements and velocities. The estimated information is subsequently applied to the calculation of stresses in both measured and unmeasured locations and, thus, to the residual fatigue life estimation of the structure. The numerical results provide a significant indication of effectiveness and suggest further investigation. © Civil-Comp Press, 2016.