Three-dimensional meso-scale finite element modeling of bonded joints between a near-surface mounted FRP strip and concrete

This paper presents a three-dimensional (3-D) meso-scale finite element (FE) model for near-surface mounted (NSM) FRP strip-to-concrete bonded joints established using the general-purpose FE software package MSC.MARC. In the FE model, elements of the order of 1 mm in size are employed. The concrete is simulated using the orthogonal fixed smeared crack model while the FRP and the adhesive are treated as linear brittle-cracking materials. The FE model is calibrated and verified using results of well-documented bonded joint tests. Using the verified FE model, the failure process of NSM FRP strip-to-concrete bonded joints is carefully studied; furthermore, the local bond stress distributions and the bond-slip relationships are extracted and analyzed. This 3-D meso-scale FE model offers a powerful tool for deployment in further investigations to establish bond-slip models and bond strength models for NSM FRP strip-to-concrete bonded interfaces. While the present study is focused on NSM FRP strips, the proposed modeling approach is generally applicable to NSM FRP bars of other cross-sectional shapes.