Studies Of Steel/FRP Reinforced Glulam Beam Flexural Behaviors By A Composite Beam Element

At present,as our government attaches great importance to energy conservation and environmental protection,glulam as a kind of green environmental protection material will have a good application prospect.As the main material of modern wood structure,glulam has the advantages of high strength,unrestricted section shape,good use of inferior materials,good stress performance and green environmental protection.Meanwhile,the bearing capacity of pure glulam beams is low,large deformation,dissatisfaction the needs of practical engineering.Based on above situation,the steel /FRP plate is adopted as reinforcing material beams,the bending performance of steel /FRP plate-reinforced glulam beams are studied by creating a composite beam element in this paper.The following research is made in this paper.Based on the theory of Timoshenko beam,the Timoshenko layered composite beam shape function is derived,Timoshenko’s composite beam functions are employed to represent the displacement interpolation functions of steel/FRP plate-reinforced glulam beams.According to the structural characteristics of the glulam,a new two-node layered composite beam element and nonlinear finite element analysis procedures are developed.Both slender and moderately deep beams can be modelled by this unified beam element,and the shear-locking can be avoided successfully.Meanwhile,geometric nonlinearity and material nonlinearity are considering.The displacement interpolation function into beams geometric equations,strain matrix is obtained,and then using T.L format tangent stiffness matrix is obtained.Finally,the finite element model of steel/FRP plate-reinforced glulam beam were successfully established.On the basis of the element stiffness matrix established in the previous chapter.a nonlinear finite element program is compiled using Fortran language,6 pieces of steel plate and 3 FRP plate reinforced glulam beams are simulated using the program,and then compared with the corresponding experimental results,found that both the load deflection curve of a good match,and the composite beam model are validated the correctness of the program.Through the contrast analyses of the same reinforced timber beam,the correctness of the model and the convenience and efficiency of the analysis are demonstrated by the compiled program and ABAQUS software.Finally,the reinforcement of the beams is studied and poplar base.Douglas fir,larch is selected to compound section,12.1%~48.4% and 14.5%~56.9%,respectively increased capacity allocation of Douglas fir and larch;Then the mechanical properties of Poplar are improved with steel plate and FRP plate,the bearing capacity is increased by 10.3%~27.3% and 14.5%~44.2% respectively.Steel plate /FRP board glulam extramural bearing capacity calculation formulas are deduced.