Push-out behaviour of demountable injected vs. blind-bolted connectors in FRP decks

Abstract

The main challenge for realizing competitive hybrid steel-FRP structures, such as bridges, carparks, is to make the steel and FRP components work together. In this study shear resistance, stiffness and ductility of three types of demountable bolted shear connectors are examined. Two blind-bolted M20 shear connectors and a novel, injected steel-reinforced resin (SRR) connection are selected to perform push-out experiments in web-core FRP decks. Failure modes of excessive bearing in FRP and bolt shear failure for blind-bolted and injected connectors, respectively, are identified. Nonlinear, highly detailed finite element (FE) models were also built and validated by results of the push-out tests to provide insights to the load-transfer mechanism. Analysis of internal forces and deformation through FE results reveals that blind bolted shear connectors provide high shear resistance and slip capacity thanks to the shear sleeves and catenary effects. The injected SRR connector shows distinct and centric load transfer owing to gapless design.