Problems of lamella flanges in steel bridge construction

As the plate elements of ordinary lamella flanges always exhibit unavoidable initial geometrical imperfections, a gap always occurs between them, into which the loaded lamella is pressed under load. Given the fact that the loading is many times repeated, the above phenomenon is also many times repeated, a pronounced cumulative damage process being thereby generated. As it was manifested during the authors' tests, this leads to the initiation and propagation of fatigue cracks in the longitudinal fillet welds connecting the individual lamellas, which can, of course, imperil the safety and useful lifetime of the bridge structure concerned.