Finite Element Modeling of FRP‐Strengthened RC Beam under Sustained Load

Abstract

External bonding of FRP laminates to the tension soffit of concrete members has become a popular method for flexural strengthening. However, the long-term field performance of FRP-strengthened RC members under service conditions is still a concern, and more work needs to be done. Based on concrete smeared-crack approach, this paper presents a finite-element (FE) model for predicting long-term behavior of FRP-strengthened RC beam, which considers the time-dependent properties of all components including the aging effect of concrete. According to the comparison between theoretical predictions and test results, the validity of the FE model is verified. The interfacial edge stresses in adhesive layer were determined through appropriate mesh refinement near the plate end, and their time-dependent characteristics were investigated. The results show that creep of concrete and epoxy resin cause significant variations of the edge stresses with time. According to the research in this paper, the FE approach is found to be able to properly simulate the long-term behavior of the FRP-strengthened beam and help us better understand the complex changes in the stress state occurring over time.

Linear creep of bonded FRP-strengthened metallic structures at warm service temperatures

“…The generalised Maxwell model is used in this study to characterise the linear viscoelastic response of the adhesive. This consists of an elastic spring (Gt = ∞) and several parallel Maxwell spring-dashpot elements (Gi, ηi), as shown in Figure 2 [27,30,31]. This linear viscoelastic model is expressed as a Prony series, which in section 4 is used as an input to the Abaqus finite element software [30,32,33]:…”

Numerical Modelling of the Nonlinear Shear Creep Behavior of FRP-Concrete Bonded Joints

“… where ( ) and ( ) are, respectively, the creep compliance and elastic modulus of the Kelvin–Voigt unit, ( ) the retardation time equal to , ( ) and ( ) the creep compliance and the dynamic viscosity associated to the linear dashpot part. The creep Poisson’s ratio of the polymer is considered constant over time [ 37 , 38 ] and it is taken equal to the elastic Poisson’s ratio ( ) due to the lack of information regarding transverse strain. Thus, the relaxation modulus in the shear direction ( ) can be calculated from the relaxation modulus in axial direction ( ) according to Equation ( 5 ).…”

Effects of Stem Cutting in Rice Harvesting by Combine Harvester Front Header Vibration

“…e cause of short rice stalks has become a current research topic. e vibration behaviors of many structures are generally identified by the method of analyzing the experimental modalities [1,2]. e relationship between stem cutting and vibration state has received considerable amount of attention.…”