Push-out tests for shear connections between UHPFRC slabs and FRP girder

Abstract

This paper presents an experimental investigation on the shear connections between carbon/glass Fiber-Reinforced Polymer I-girder and Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC) slabs. Effects of straight/inclined bolt shear connectors and effective embedment depth-to-bolt diameter (hef/d) ratios were investigated. Fourteen push-out tests were conducted to evaluate the load–slip behavior and the ultimate resistance of the bolt shear connectors. With the use of the UHPFRC, the hef/d ratio needed for obtaining a shear connector failure mode was 2.7 times lower than that obtained from 43 push-out tests in the literature for normal weight and lightweight concrete slabs. The inclined bolt shear connectors showed a more ductile behavior than the straight bolt shear connectors. The experimentally obtained ultimate resistance of the bolt shear connectors was compared against the equations provided by ACI 318-11, AISC 2011, AASHTO LRFD 2010, PCI 2004, and EC-4 2004. An empirical equation to predict the ultimate shear connector resistance was proposed and validated by the experimental data. Idealized load–slip models and equations to predict the load versus slip relationship for all push-out tested specimens were proposed. Curve fitting was performed to find fitting parameters for all tested specimens and the results showed a very good correlation with the experiments.