Numerical Analysis of Glulam Beams Reinforced With CFRP Plates

Abstract

This paper presents an analysis of bending behaviour of glued laminated timber (glulam) beams reinforced with carbon fibre reinforced polymer (CFRP) plates, based on finite element numerical modelling. Nonlinear 3-dimen­sional model was developed and validated by experimental tests carried out on unreinforced beams and beams reinforced with two different reinforcement arrangements. Suitable constitutive relationships for each material were utilised in the model, as well as anisotropic plasticity theory for timber in compression. Adhesive bond between CFRP plate and timber was modelled as a perfect connection. Beam failure in the model was defined by maximum stress criterion. The predicted behaviour of beams has shown good agreement with the experimental results in relation to load-deflection relationship, ultimate load, elastic stiffness and strain profile distribution. The non-linear behaviour of reinforced beams before failure was also achieved in the numerical analysis, confirming the finite element model to be accurate past the linear-elastic range. Experimentally tested reinforced beams usually failed in tensile zone after compressive plasticiza­tion of top lamination, which was also simulated in the numerical model. The results proved that the load carrying ca­pacity, stiffness and ductility of glulam beams were successfully increased by addition of CFRP plate at tension side of the section.

The Effect of Glue Cohesive Stiffness on the Elastic Performance of Bent Wood–CFRP Beams

“…The last two authors [ 41 , 42 ] conducted a detailed statistical analysis of the results. Glisovic [ 43 , 44 ] tested glued laminated timber reinforced with CFRP in various configurations such as those presented by Schober ( Figure 4 b and Figure 5 d,e). In another work [ 45 ], he proposed FE modelling as performed by Nowak [ 35 ] and Khelifa [ 46 ].…”

“…Glisovic [ 43 , 44 ] tested glued laminated timber reinforced with CFRP in various configurations such as those presented by Schober ( Figure 4 b and Figure 5 d,e). In another work [ 45 ], he proposed FE modelling as performed by Nowak [ 35 ] and Khelifa [ 46 ]. Subhani [ 47 ] suggested strengthening laminated beams with CFRP in two variants—at the bottom of the beam and in a U-shape ( Figure 4 a,d).…”

“…Then, they change the material of the bonding layer between wood and CFRP from an epoxy resin to a PRF (phenol resorcinol formaldehyde) adhesive. In the latest work, Raftery [ 50 ] performed FE modelling based on the assumptions in the papers of Nowak [ 35 ], Glisovic [ 45 ] and Khelifa [ 46 ]. Osmannezhad [ 52 ] proposed gluing GFRP on epoxy glue between the layers of GLT in various configurations as shown in Figure 7 b,c.…”

“…The literature survey showed that researchers neglected the glue layer stiffness when modelling the described girders [ 35 , 45 ]. The authors of this paper state that, in case of PUR (soft glue compared to epoxy), including the cohesive stiffness of the connection has a significant influence on bent girders.…”

Mechanical Properties of Laminated Veneer Lumber Beams Strengthened with CFRP Sheets

“…Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland, e-mail: kossak@tu.kielce.pl external reinforcement [9], in most cases glued with epoxy resin adhesives or attached by means of mechanical fasteners [5]; or as internal reinforcement glued into previously prepared grooves [11,12,18]. The second solution allows the design to hide the material inside the outline of the crosssection, thus maintaining the original appearance of the element and securing the combination of the wood-glue-composite against the external factors.…”