The fatigue behavior of ortho-composite-slabs with dowel strips for road bridges under transverse loads

The so-called ortho-composite-slab combines the orthotropic stiffened steel deck as a lightweight construction for medium and long span bridges with the robustness of composite slabs to handle increasing traffic loads. The structure consists of an orthotropic stiffened steel deck, a relatively thin layer of reinforced concrete and dowel strips with teeth in the form of clothoids as shear connectors. In addition to the significant advantages of low deadweight and long service life, the ortho-composite-slab is characterized by fast and economical production. The construction was investigated by a comprehensive experimental test program in combination with structural-mechanical calculations as part of the AiF-FOSTA research project P 1265 at the TUD Dresden University of Technology. Within the scope of the project, basic principles for the design of ortho-composite-slabs with dowel strips were developed. This paper first gives an overview of the experimental test program. This is followed by a detailed discussion of the static and cyclic tests on sections of the ortho-composite-slab (so-called beam tests). The statistical evaluation of the tests and the assignment to a fatigue resistance curve are presented. • The OC-slab has a sufficiently high load-bearing capacity for load transfer of local wheel loads in the transverse direction. • The welded connection of the dowel strips to the cover plate under transverse loads can be assigned to FAT class 80. • The OC-slab with dowel strips can endure an unlimited number of load cycles in accordance with prEN 1991-2. • Evenly distributed transverse concrete cracks with permissible crack width have no significant influence on the resistance. • The dowel strips itself as well as the construction of the OC-slab with dowel strips have a large redistribution potential.