Experimental investigation on mechanical behavior of FRP-to-steel adhesively-bonded joint under combined loading-part 1: Before hygrothermal aging

Abstract

a b s t r a c tDue to various advantages of fiber-reinforced polymer (FRP) decks, the FRP-steel composite girder system is being increasingly used in new bridge constructions as well as rehabilitation projects for old bridges. This paper presents the first part of the research project, focusing on mechanical behaviors of adhesivelybonded joints between FRP sandwich decks and steel girders before hygrothermal aging. A specific tensile-shear loading device was designed with the capacity to provide the combination of tensile and shear loads in six different ratios. Ultimate failure loads, load-deformation behaviors and failure modes of un-aged adhesively-bonded joints were investigated experimentally and compared regarding to different loading angles. Under the shear loading, the failure of adhesive joints occurring in the adhesive layer was cohesive failure, at a location close to the steel support. Under the tensile and four combined loading conditions, the failure mode was the combination of fiber breaking (or FRP delamination) and interfacial adhesion failure between FRP sandwich deck and adhesive layer. Load-deformation curves indicated that the non-homogeneous characteristic of the adhesive layer was evident, which induced the eccentric loading on the adhesive joints and stress redistribution during the test process. The tensile-shear failure criterion of the adhesive joint was addressed, regarding to the vectorially separated tensile and shear stress.

Structural Response of Bonded Joints between FRP Composite Strips and Steel Plates

“…All failure mechanisms that were identified correspond to those already presented by other authors in previous research works [33][34][35][36][37][38][39]. However, only 6 of the 34 specimens failed by a single dominant mechanism, while the other 28 developed combined failure modes, characterized by two or three failure patterns.…”

Design, fabrication, and construction of a freeform GFRP facade

“…According to the instruction of CBSR-A/B and Table 4, the ingredients and properties are similar to the adhesive BUFA-BONDING PASTE 740-0110 applied in our previous researches on FRP-to-steel joint Bijlaard 2013, 2014;Jiang et al 2015aJiang et al , 2015b, which properties have been already studied. In China, CBSR-A/B is massively available in the market, however, there was no related adhesive parameter when it was applied between GFRP and steel, and the manufacturer of CBSR-A/B could not provide them, either.…”

Thermal Stress Analysis of the Adhesive Layer in Composite Laminates

“…The weakest region of composite structures is the interface unit between the composite element and the metal/composite member bonded using epoxy resin adhesives. Therefore, considerable research has been conducted to investigate the fatigue performance of adhesive interface units, mostly on fiber reinforced plastics (FRP) composite joints [3][4][5][6][7][8][9][10]. It was suggested that more research should be conducted to understand bonded joint behavior and to improve joint design [11].…”