Analysis Of Static Performance In Steel-wood Connection

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. In this paper, bolt and high strength structural adhesive are used to connect steel members and wood members, and the combined members show good mechanical performance. In addition, energy-saving and low-carbon concepts are also performed well in this combined members. Therefore, the results of this research are not only of strong theoretical significance, but also have important practical value.Bolted connection is one of the main connection for the wood structure, which have high resistance ability, large stiffness and convenient for construction. Further study the behavior of bolted connection is significant for theory and practice. Adhesive specimens have broad application for their advantages such as low cost, light mass, high strength, uniform stress distribution and fatigue resistant. On the basis of tests, static performance of two kinds of connection are researched. The main research contents include:(1) The bearing capacity of timber structure is closely related with its material performance, so in this paper, material properties of specimens were tested:density, moisture content, young’s modulus, bending strength, compressive strength parallel to grain and bolt bending strength, other parameters were calculated by the experimental data, which were useful for further research.(2) Based on the experiments of nine groups of specimens, the static performance of bolted connection were studied. The yield mode is considered as "one hinge" mode when the bolt diameter range from6mm to10mm, and the typical failure mode is bolt bending failure and part of bearing failure in wood pin groove at the same time. The research results indicated that not all bolts forced evenly, and the bottom bolt beared larger stress. The factors, which have influence on initial stiffness, yield strength and ultimate strength, are bolt pitch, bolt diameter and stave thickness. At last, suggestions were carried out based on the comparison with normative design.(3) Based on the experiments of six groups of specimens, the static performance of adhesive connection were studied. The typical failure mode is brittle failure mode, and the typical damage mode is adhesive failure. The load-displacement relationship and load-strain relationship of specimens were analyzed, which showed that the mechanical performance of specimens was linear-elastic in stressed process, and the strain distribution in H-beam was contrast with the board. An method was made to improve ductility by using bolted connection and adhesive connection, two groups of mixed specimens were tested, which showed that the combined specimens were not ideal, it was suggested that close connection was better to improve ductility. At last, Finite element models were established to verify that the constitutive models were reasonable, parameters were analysed and the suggested values for design were given.