An experimental study on static behavior of a GFRP bridge deck filled with a polyurethane foam

The static behavior of an orthotropic bridge deck made of glass fiber reinforced polymer (GFRP) and polyurethane foam was investigated experimentally. The bridge deck consisted of GFRP unit modules with rectangular holes filled with foam to improve the structural behavior in the transverse direction. It was found that, although the elastic modulus of the foam compared to the homogenized modulus of the GFRP deck was about the order of 10^-3, the structural behaviors in the transverse direction such as the nominal strength, stiffness, etc. were greatly improved when the GFRP bridge deck was filled with foam. Because of the low mass density of the foam used in this study, the bridge deck was still light enough while the structural properties were improved significantly. Webs of the foam-filled modules did not significantly contribute to strength development of the deck. However, propagation of a crack initiated in a module was caught by the webs so as to limit the crack to the inside of that cell only. This made the load-displacement behavior of the foam-filled GFRP deck less brittle. The longitudinal response of the GFRP deck was improved with the foam. The strength was increased about 20% but the elastic modulus was not improved.