Maik Kopp

Design of composite dowels as shear connectors according to the German technical approval

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. Advantages over headed studs are in particular the increased strength, the sufficient deformation capacity even in high strength concrete and the simple application in steel sections without upper flange. However, missing provisions in standards for composite dowels with the economic clothoid and puzzle strip have led to retentions of clients and delays in the approval process. Hence, the aim of the recently finished German research project P804 [15] founded by FOSTA- Research Association for Steel Application was to solve open questions concerning these innovative shear connectors and to prepare a general technical approval available for any design office and construction company. In this paper design concepts for ultimate limit state and fatigue limit state, structural design principles and instructions for production and construction are presented and background information are given.

Field measurements at a composite bridge with composite dowels as shear connectors

Within the demonstration project ECOBRIDGE, funded by the Research Fund for Coal and Steel (RFCS), a monitoring program has been developed and applied to survey a composite railway bridge. The stress distribution between concrete and specially designed composite dowels, which have a better fatigue resistance compared to conventional headed studs, has been investigated as well as the forces in several rail support points. The German railway operator DB Netz AG requested the survey to prove the applicability of state of the art calculation methods, which were not part of compulsory codes.