Research On EB-FRP Interface Numerical Simulation And Bond-Slip Model Considering Failure Mode

With the increasing demand for concrete structure reinforcements,externally bonded FRP(EB FRP)has been widely applied.For EB FRP system,its effectiveness depends on the bond performances of FRP-Concrete interface.As a result,it is necessary to understand the performances for using this strengthening technique reasonably in practice.Numerical simulation is a common method to study this problem.Compared with physical tests,it could accurately capture the whole debonding process of the interface and provide stress field in this process.Additionally,numerical simulation makes it possible to carry out unlimited parameter analysis.However,most of existing studies are executed based on the assumption that the failure only occurs in concrete base.This fails to reflect the true failure modes of the interface.On that ground,this paper focuses on a numerical simulation for FRP-Concrete interfacial bond-slip behaviors in EB FRP systems.A typical single shear test is employed as a reference object,and a set of three-dimensional finite element model considering various failure modes is established based on concrete damage plasticity theory and cohesion theory.Then,a parameter analysis is carried out to revise existing interfacial capacity models together with other test data collected herein.Study contents are shown as follows:(1)Interface elements are employed to simulate adhesive layer in EB FRP for establishing a finite element model which could realistically represent the properties of FRP-concrete interface.(2)Traction-separation and Benzeggag-Kenane models are used to simulate the debonding damage of interface elements.Plasticity damage model is adopted to simulate the nonlinear behaviors of concrete.Key factors and configurations of these model are investigated in this paper.(3)Extensive test data is collected to revise existing bond-slip models of the interface.A new interfacial bond-slip model is proposed,which could consider the effect of such factors as adhesive layer thickness.(4)A parameter analysis is carried out based on the proposed numerical simulation method for understanding the effect of adhesive layer thickness on the interfacial capacity,concrete damage,and interface debonding process of EB FRP.(5)A new comprehensive interfacial capacity model is developed through revising existing models based on the parameter analysis results and collected test data.