FIRE RESISTANCE OF TIMBER JOINTS WITH STEEL FASTENERS

Fire safety is a major concern in the design of timber construction. Wood is combustible material. The thermal response of timber connections is usually the main factor in evaluating the overall load-bearing capacity of wood structures exposed to fire. The analysis of timber joints under fire conditions is difficult and complex. Finite element model is developed to predict the thermal behavior of bolted wood-to-wood joints exposed to fire. In fire, the material characteristic depend on the temperature. The thermal model is continuous, taking into account the thermal continuity between the joint components. Also, the thermal model is used to predict the evolution of the temperature field inside the connection. The paper presents a summary of results from a numerical studies of the fire behavior of wood-to-wood timber connections with steel bolt. As a result of computer simulations the temperature distribution was obtained. During fire exposure, the timber section is reduced and steel bolt reduces strength. Load-carrying capacity per shear plane in fire conditions was calculated using two methods: design methods according to EN 1995-1-1 [5] and reduced load method according to EN 1995-1-2 [6]. In the first approach, the timber section loss and steel strength reduction during the fire were taken into account.

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1. Audebert M., Dhima D., Taazount M., Bouchair A.: Numerical investigations on the thermo-mechanical behavior of steel-to-timber joints exposed to fire, Engineering Structures, no. 33, 2011, p. 3257–3268.
2. Barber D.: Determination of fire resistance ratings for glulam connectors within US high rise timber buildings, Fire Safety Journal, no. 91, 2017, p. 579–585.
3. Domański T.: Wybrane zagadnienia niezawodności konstrukcji drewnianych. Wydawnictwo PK, Cracow 2016.
4. EN 1993-1-2 Eurocode 3: Design of steel structures – Part 1-2: General rules – structural fire design, PKN, Warsaw 2007.
5. EN 1995-1-1 Eurocode 5: Design of timber structures – Part 1-1: General – Common rules and rules for buildings, PKN, Warsaw 2010.
6. EN 1995-1-2 Eurocode 5: Design of timber structures – Part 1-2: General – Structural fire design, PKN, Warsaw 2008.
7. Franssen J.M., Gernay T.: Modeling structures in fire with SAFIR: theoretical background and capabilities, Journal of Structural Fire Engineering, vol. 8, 2017, issue 3, p. 300–323.
8. Maraveas C., Miamis K., Matthaiou E.: Performance of timber connections exposed to fire, Fire Technology, no. 51, 2013, p. 1401–1432.
9. Moss P., Buchanan A., Fragiacomo M., Austruy C.: Experimental testing and analytical prediction of the behavior of timber bloted connections subjected to fire, Fire Technology, no. 46, 2010, p. 129–148.
10. Peng L., Mehaffey J., Mohammad M.: Predicting the fire resistance of wood-steel-wood timber connections, Fire Technology, no. 47, 2009, p. 1101–1119.
11. Racher P., Laplanche K., Dhima D., Bouchair A.: Thermo-mechanical analysis of the fire performance of dowelled timber connection, Engineering Structures, no 32, 2010, p. 1148–1157.
12. Thi V.D., Khelifa M., Oudjene M., El Ganaoui M., Rogaume Y.: Finite element analysis of heat transfer through timber elements exposed to fire, Engineering Structures, no. 143, 2017, p. 11–21.