Experimental and numerical study on mechanical behavior of an adhesively-bonded joint of FRP–steel composite bridge under shear loading

Due to the composite action between the Fiber-Reinforced Polymer (FRP) decks and steel girders, the deck and girder tend to bend together to carry the loading, which induce the shear stress in the adhesively-bonded joint between them. This paper presents an experimental and numerical study of the adhesively-bonded joint under shear loading. The experimental study shows that the average ultimate failure load of specimens pretreated by using sand paper and sand blasting is more than three times of that of specimens pretreated by only using acetone. Further comparison on failure modes confirms that the sufficient surface pretreatment can improve the bonding quality between the adhesive layer and the steel support. Subsequently, a three dimensional Finite Element (FE) numerical model is developed using ABAQUS 6.8. The FE analysis results are validated by experimental works, focusing on the shear deformational response of the adhesively-bonded joints. With the validated FE model, three-dimensional nature of the stress distribution and stress singularity at the interface between the adhesive layer and the steel support are investigated. Further study is performed on the mesh density of the FE model, to investigate the mesh dependence of stress distribution.