Eur. J. Wood Prod. (2012) 70:225–232 DOI 10.1007/s00107-011-0539-x ORIGINALS ORIGINALARBEITEN Behavior of bolted timber joints subjected to high temperatures Poliana Dias de Moraes · João Paulo C. Rodrigues · Nadia Diana F. Correia Received: 8 December 2010 / Published online: 30 March 2011 © Springer-Verlag 2011 Abstract This paper presents experimental research on the behavior of bolted timber joints subjected to high tempera- tures. Tests for the determination of the embedment strength parallel to the timber grain and the load-bearing capacity of single- and three-bolt joints were carried out. The tested temperatures were 20, 50, 100, 150, 200, and 230 °C. The specimens were made of Pinus taeda timber with a density varying from 427 to 524 kg/m 3 and moisture content of 12% at 20 °C. The results have shown that the temperature and moisture content signiﬁcantly inﬂuence the load-bearing ca- pacity of the joints. Higher temperature leads to a nonlin- ear decrease of resistance, with minimum values at 50 and 100 °C for the single- and three-bolt timber joints, respec- tively. This behavior is associated with degradation of the polymers and changes in the moisture content of the timber. Verhalten von Bolzenverbindungen bei hohen Temperaturen Zusammenfassung In dieser Arbeit wird das Verhalten von Bolzenverbindungen, die hohen Temperaturen ausgesetzt sind, untersucht. Geprüft wurde die Lochleibungsfestigkeit in Faserrichtung sowie die Tragfähigkeit von Verbindungen mit einem und mit drei Bolzen bei Temperaturen von 20, 50, 100, 150, 200 und 230 °C. Die Prüfkörper bestanden P.D. de Moraes ( ) Departamento de Engenharia Civil, Universidade Federal de Santa Catarina, Rua João Pio Duarte Silva, s/n, Cx. Postal 476, Córrego Grande, Florianópolis, 88040-970, SC, Brazil e-mail: ecv1pdm@ecv.ufsc.br J.P.C. Rodrigues · N.D.F. Correia Departamento de Engenharia Civil da Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Rua Rui Luís Reis Santos, 3030-788 Coimbra, Portugal aus Kiefernschnittholz (Pinus taeda) mit einer Rohdichte zwischen 427 und 524 kg/m 3 und einem Feuchtegehalt von 12 % bei 20 °C. Die Ergebnisse zeigten, dass die Temperatur und der Feuchtegehalt einen signiﬁkanten Einﬂuss auf die Tragfähigkeit der Verbindungen haben. Höhere Temperatu- ren führen zu einer nicht linearen Abnahme der Tragfähig- keit, mit dem niedrigsten Wert bei 50°C bei Verbindungen mit 1 Bolzen bzw. 100°C bei Verbindungen mit drei Bol- zen. Bei diesem Verhalten spielen der Polymerabbau und die Holzfeuchteänderungen im Schnittholz eine Rolle. 1 Introduction The structural safety of timber structures depends on their capacity to support loads while maintaining the speciﬁed service requirements. This capacity is related to the resis- tance and stiffness of the structural elements and joints. The joints are important parts of a timber structure and should withstand more than the connected elements. The design criteria of timber joints are currently pre- sented in EN 1995-1-2 (2004) for ﬁre and in EN1995-1-1 (2004) for room temperature case. However, the application of these methods can present problems for temperatures be- tween the room temperature and the timber charring temper- ature (300 °C) that can be corrected from results of research work to be carried out in the near future. The behavior of timber joints subjected to ﬁre is complex and still not fully understood. The assessment of the joint failure time, the inﬂuence of the type of joint and the exis- tence of metal elements within the joint on its thermal ﬁeld and the modes of failure require more research. Several ex- perimental, numerical and analytical studies have been car- ried out on timber joints at high temperatures to obtain an- swers to these and other questions.