Composite dowels as shear connectors for composite beams - Background to the design concept for static loading

Composite dowels are known as powerful shear connectors in steel-concrete-composite girders. More and more they are used in practice, especially for prefabricated composite bridges. Compared to headed studs they provide an increased strength. They also show a good deformation capacity even in high strength concrete. Furthermore, the application in steel sections without upper flange is very simple. Nevertheless, missing standards for composite dowels with the economic clothoidal and puzzle shape have led to hesitations in application which is often due to delays in the approval process. Hence, the aim of the finished German research project P804 funded by FOSTA - Research Association for Steel Application was to solve open questions concerning these innovative shear connectors and to prepare a general technical approval [1] available for any design office or construction company. Since May 2013 the composite dowels with clothoidal and puzzle shape are regulated in the technical approval. This paper presents the background information to the derived technical rules for ultimate limit state, structural design principles and instructions for production and construction and provides further background information.