Mechanical Properties Of CLT In China Fir With Different Thicknesses

Cross laminated Timber(CLT), is a kind of new building materials, the blank alternately laminated structure, overall performance has been greatly improved, with high dimensional stability, excellent mechanical strength, and it can be used as a tall wooden structure buildings, layers up to ten or more. It is well known as the future alternative concrete building materials.CLT has been highly recognized in Europe, North America and other countries, the development is very rapid, but the domestic research about CLT less, greatly limits the development and popularization of CLT in china. Methods through experiments and theoretical analysis, combined with the study of flexural and shear properties of CLT component, combined with foreign experience in production are introduced and the evaluation system of CLT production process.The focus of this paper mainly includes the following several aspects:(1) Read the foreign literature and summarized and briefly introduced the details of CLT structure and production process;(2) Under the premise of the overall size of CLT, the influence of thickness on the structure and properties of CLT was studied;(3) Under the premise of the overall size of the CLT, the influence of the thickness ratio of the odd and even layer on the performance of the CLT structure is studied.(4) Using the existing CLT static analysis theory to calculate the mechanical properties of CLT components based on the above test conditions, and the results are compared with the results of mechanical tests.(5) Using Ansys software to carry out a simple analysis of the above research, the results were compared with the experimental results.Through the research of this paper, the following conclusions are drawn:(1) rolling shear and fracture of laminates and adhesive layer faults and layer slip is CLT structure under vertical load is the main failure form, failure forms of members and the plate thickness is greater relevance.(2) the research on the static analysis theory of CLT components abroad has been mature enough, which is the theoretical basis for the development and application of CLT structure in China;(3) under the premise of the same thickness, three layers of CLT components of the main failure mode is single, basic bottom plate fracture, and five layers and seven layers of structure failure mode of relatively complex, in addition to the bottom plate fracture, but also prone to layer cracking and end head plate slip phenomenon;(4) under the premise of wood materials, the greater the thickness of CLT laminates, the better the flexural performance of the CLT structure, and the thinner the thickness of the laminate, the better the shear resistance of the component;(5) under the premise of satisfying the standard thickness, should try to increase the CLT odd layer thickness, and a reduction in the thickness of the laminate even, so you can in under the condition of not improving the timber consumption effectively improve CLT components of bending and shearing performance.