Experimentelle Untersuchungen an vorgespannten Durchlaufträger-Teilsystemen zum Einfluss nicht mehr zugelassener Bügelformen auf die Querkrafttragfähigkeit

Because of higher demands on existing bridges, in particular due to a steady increase in traffic loads as well as various adjustments in the design standards, the strength evaluation of prestressed concrete bridges often shows pronounced calculated deficits regarding shear capacity. In practice, however, often no corresponding damage to the structure is visible. This discrepancy is currently an active field of research. In this context the influence of no longer permitted stirrup types, as well as a low shear reinforcement content in general, on the shear capacity of prestressed concrete bridges are to be quantified. Extensive experimental investigations were carried out at the Technical University of Munich on a total of eleven prestressed concrete girder elements with an innovative test concept using the substructure technique. Tests were carried out on the one hand with stirrups having a short lap length, stirrups open on one side with straight bar ends and plug-in stirrups as well as on the other hand with conventional stirrups and without any shear reinforcement. With the help of quasi-continuous fibre-optical strain measurements, important new findings on the influence of these stirrup types on shear capacity were obtained.