Study On Flexural Behavior Of Steel-wood Composite Beam

Timber construction has the following advantages:superior energy conservation, environmental protection, comfortable, harmony with environment, but wood has low design strength. In each kind of steel structure design, we usually meet the problem that how to keep the stability. The paper presents a new type of I-section composite beam based on combining the characteristics of two material, which takes welded H-shape steel as the backbone and pasted wood board on the up and down surface of the flange of steel. Experimental study and theoretical analysis have been done on flexural properties of them. The results indicate that steel-wood composite beam that is formed of two different materials steel and wood by structural adhesive bonding is possible. Through the strengthening of wood, composite beam will not occurs instability, and the steel can go into the plastic development stage to full use of the material strength. The composite effects are obvious, mechanical properties are good, and this composite beam can be used in construction engineering as the bearing capacity components.Experimental study on the flexural behavior of 9 composite beams was carried out by the parameters of the thickness of wood, the thickness and width of the flange of steel, the height of the web of steel. The author monitored the development of strain in the steel sheet and wood board and the deflection of beam. The failure process, failure modes, failure mechanism were investigated, and then the ultimate bearing capacity and bending stiffness of composite beam were explored. Experiment results indicate that H-shape steel and wood board can form an excellent composite cross-section, and the strain in the composite cross-section is linearly distributed. Specimen load vs span-deflection curve has elastic and inelastic stage, and specimen damages because of the fracture of wood at the span of lower flange finally.Based on bearing capacity superposition method, the paper presents the simplified computational formula of mid-span deflection and bending bearing capacity. The formula results fit well with the experimental results with high accuracy, which can be provided as the design basis on the application of composite beam.This paper carries on a finite element numerical analysis for bending performance of H-shape steel-wood composite beams though ABAQUS, and gets on systematic research on some key technology such as material model definition, finite element modeling, spring unit generating and after-treatment. The analysis result shows that the calculation results of ABAQUS largely accord with the experimental results, which indicates that numerical simulation technology is reasonable and feasible. At the same time, the main parameters affecting bending performance of composite beams are analyzed, including the yield strength of steel, the thickness and width of H-shaped steel flange, the thickness of wood, the height and thickness of steel web.