Hello, teachers and classmates. My

Hello, teachers and classmates. My name is Wang Jiaxuan. Today we are going to talk about wood Construction. Wood is a resource-rich and affordable building material that comes from a renewable resource - trees, which are often planted purposefully and then harvested with a specific end product in mind. Because of its origin, wood as a building material has inherent characteristics that users should be familiar with. For example, two planks of the same species and size may not have the same strength, although they are cut simultaneously from trees growing side by side in a forest.The task of describing such biologically heterogeneous materials is not an easy one. But it can be described accurately and much better than in the past because research has provided a lot of useful information about the properties and structural behaviour of wood. For example, studies have shown that without modification, compression levels cannot be applied to the tensile side of a deep bending member. Nor can it be used for tensile strength comparable to compressive strength. In addition, the research also gives a better estimate of the engineering quality. Estimating the engineering quality of a piece of wood no longer requires only visual inspection, with averages as the key. In the past, residential construction has been based on practice rather than engineering design, resulting in underutilization of wood strength. Now, with a better understanding of wood, the introduction of reasonable structural design standards, and the development of economic manufacturing processes, home buildings have been better and more efficient use. The improvement of adhesive also helps to improve the wood structure. In particular, the laminating process, which uses adhesives to bond thin sheets into deep wood, improves the properties of the wood. Not only do you get stronger structural components, but you can also place the higher grade wood in the area where the stress is greatest and the lower grade wood in the area where the stress is lowest, for the benefit of the economy as a whole. Although there is a great deal of variation in the strength of the wood, the wood can be converted into plywood of predictable strength with very little variation in strength.