Переваги та недоліки γ-методу для розрахунку міцності ПКД панелей при згині

Abstract

Cross laminated timber or CLT is a new building material that is widely implemented in the construction of multistorey residential and office buildings. This material has become widespread in Europe, the United States and Canada and has been in active use for over 20 years. At the present stage of the panel construction, only the German national standard DIN EN 1995-1-1 / NA (2010) and the Austrian ÖNORM B 1995-1-1 (2014) standard for the design of timber structures contain recomendations for the design and construction of CLT panels buildings. The calculation of the CLT panels strength for different types of stress state can be performed only on the basis of technical conclusions of laboratories and product certificates containing instructions and correction values for the calculation of CLT panels of a specific manufacturer. The next revision of Eurocode-5 in 2022 will have significant regulations and requirements for the design and calculation of houses using CLT panels. There are three methods for calculating the bending strength of panels based on a specific scheme of approximation: the gamma method, the Tymoshenko method, and the shear analogy method. The gamma method treats the CLT panel as a flexible beam, similar to the beam of the Dereviagin system on lamellas or Kubler cubes, where the transverse layers of the boards are considered as pliable and not taken into account in calculating the geometric characteristics of the CLT cross sections. Each technique has its advantages and disadvantages as it has a number of specific assumptions to simplify the calculations. This paper highlights the advantages and disadvantages of the gamma method, which is more prevalent than other techniques and is found in many technical opinions of various CLT panels manufacturers. The analysis of the drawbacks of this technique avoids a number of inaccuracies in the calculation results.