Punching capacity of prestressed concrete bridge decks under fatigue

Previous research showed that the capacity of existing slab-between-girder bridges is larger than expected based on the punching shear capacity prescribed by the governing codes, as a result of compressive membrane action. A first series of fatigue tests confirmed that compressive membrane action also acts under cycles of loading. However, a single experiment, in which first a number of cycles with a higher load level and then with a lower load level were applied, seemed to indicate that this loading sequence shortens the fatigue life. This topic was further investigated in a second series of fatigue tests with three static tests and 10 fatigue tests. The parameters that were varied were the sequence of loading and the effect of a single or a double wheel print. The results show that the sequence of load levels does not influence the fatigue life.