Schubübertragung in Betonierfugen mit nichtmetallischer Bewehrung

Non-metallic reinforcement is increasingly used in construction practice. According to current
guidelines, it cannot yet be used to transfer shear forces. This is due to the anisotropic material
behavior of non-metallic reinforcement compared to steel reinforcement as well as the lack of
knowledge on load-bearing behavior from composite shear tests.

Within the scope of the diploma thesis, two test series are developed, one investigating the shear
strength in a pure shear test and on the other the load-bearing behavior in combination with concrete
in a composite shear test. Glass fiber reinforced and carbon fiber reinforced reinforcement
are compared in the pure shear test. In the composite shear test, the behavior of unreinforced
specimens is also investigated. Further variations are made by using different degrees of roughness
and reinforcement. Within the evaluation section, a comparison is made, by designing the
shear force transmission in joints according to the approach of Eurocode 1992-1-1 (2011) and
according to the approach of the fib-Model Code (2010).

The test series show that non-metallic reinforcement participates ductilely in the load transfer
with respect to shear in joints. The reinforced specimens have a residual load-bearing capacity
with the concrete failure (large load drop) in comparison with the unreinforced specimens.
There is a local maximum force after the concrete failure, especially in the case of the two-layer
design. This is true for glass fiber reinforced specimens as well as for carbon fiber reinforced
specimens, and the tests clearly show the influence of the type of reinforcement on crack initiation
and thus advance warning of failure. Different design approaches show that the guidelines
designed for steel cannot be adopted identically for non-metallic reinforcement. However, the
experimentally-determined load capacities of the latter do not deviate significantly from the
mathematically-determined load capacities, such that a modification of individual factors in the
design approach provides sufficient safety in the design.

The influence of further parameters is shown and more extensive studies are necessary to establish
a design approach adapted to non-metallic reinforcement.