Implants for load introduction into thin-walled CFRP-reinforced UHPC beams

Combining two high-performance materials - viz. ultra-high performance concrete (UHPC) as the matrix, and carbon fibre reinforced polymers (CFRP) as the reinforcement - opens up new possibilities of achieving concrete elements with thin walls and minmial weight. This strategy, however, results in a higher degree of material utilisation, which impedes load transfer from such thin-walled concrete elements to auxiliary constructions such as superordinate load-bearing systems. The authors present a solution for the load transfer from very slender CFRP-reinforced UHPC beams to its supports via steel implants (Sobek and Mittelstädt, 2012; Kobler, 2013; Mittelstädt, 2015). In this paper, the conceptual design of three different types of implants is presented. The geometry of the implant and especially the connection of the CFRP reinforcement to the steel implant are examined in detail. For this paper the authors tested beams with three different types of implants and three different configurations of the textile CFRP reinforcement serving as structural and shear reinforcement.