Travi da ponte composte acciaio-calcestruzzo soggette a carichi viaggianti - Comportamento ciclico della connessione

The paper deals with a numerical procedure for the analysis of the structural behavior of steel-concrete composite beams subjected to moving loads, considering an inelastic experimental based relationship between the shear force and the slip of the connectors. The procedure allows to determine the oscillograms of the slip and the shear force of each connector corresponding to the transit of an assigned loading pattern. Fatigue checks, based on the strain-life approach can be carried out using such a numerical tool. The procedure was used to study the cyclic behavior of the connection of a 40 m span simply supported bridgetype beam subjected to a severe loading model: fatigue model 1 (ENV 1991-3) with a heavy abnormal 15 axles vehicle (3600 kN). The results allowed to assess the damage accumulated in the connectors due to one thousand transits of the considered load. Significant damage occurs in the studs close to mid-span.