Finite Element Analysis of Pure Bending Properties of Square Steel Tube-Wood-Concrete Members

Wood is widely used in engineering because of its high load-bearing capacity, green and renewable. In order to reduce the amount of concrete in steel pipe concrete members, and reduce structural weight, the wood is placed in the steel pipe concrete, to form the steel pipe-wood-concrete members. Since the pure bending member is the foundation of the compression bending member and the auxiliary of the compression bending member, the study of the mechanical properties of the pure bending member is of great significance. Reasonable selection of steel, concrete, wood of the constitutive model, this paper uses ABAQUS software to establish a square steel pipe-wood-concrete pure bending member refined analysis model, analyzing the typical member of the stress and neutral axis height change rule, revealing the square steel pipe-wood-concrete pure bending member of the working mechanism. On this basis, the influence of different steel yield strength, steel content rate, concrete compressive strength, wood core cross-section form, wood configuration rate on the flexural performance of the member was studied.
The results indicate that substituting wood for core concrete in the steel tube-wood-concrete members can enhance their flexural capacity and ductility. Additionally, it leads to a 16% reduction in the overall weight of the structure, and its strength-to-weight ratio is significantly increased. When the yield strength of steel components is increased from 235 MPa to 420 MPa, the flexural capacity can be increased by 35. 4%-63. 5%, and the ductility coefficient can be increased by 5. 5%-13%. When the steel content is increased from 8. 5% to 18. 1%, the flexural capacity can be increased by 24. 5% to 71. 4%, and the ductility coefficient can be increased by 4.8% to 16%. The increase of concrete strength has no significant effect on the flexural performance of the members, but it reduces the ductility of the members. The bending capacity of wood increased from 18. 1% to 100%, and the ductility coefficient increased by 5. 4% to 18. 8%. Wood is more likely to play a role when the allocation rate is 8. 1% to 32. 7%. Therefore, when the ratio of wood is 8. 1%-32. 7%, by increasing the yield strength and steel content of the steel component, the ductility and flexural capacity of the composite members can be further enhanced.