The bearing strength perpendicular to the grain of locally loaded timber blocks

The compressive strength perpendicular to the grain is one of those wood properties that are important for structural design but are difficult to tackle due to its semi-plastic behaviour. It depends on deformation, the specimen type and loading condition. For long no common definition for the standard compressive strength was agreed. A comprehensive survey of research work is given by Augustin and Schickhofer [1], Kollmann [4], Gehri [3], Madsen [6] and Blass and Görlacher [2]. Some empirical models were proposed by Madsen [6] and Riberholt [7]. Van der Put [10] presented a physical model as early as 1988, based on plasticity theory. He showed the ability and accuracy of his model with test data from literature. Despite of his effort the absence of any reference to his model in later publications indicate the model is not well understood. To convince those who are still in doubt a comparison follows between the Van der Put model and the empirical model of Eurocode 5. It is concluded that Eurocode 5 is unsafe while Van der Put's model is by far superior

Duration of load effects on the splitting behaviour of timber loaded perpendicular to the grain by dowel-type connections

The duration of load (DOL) effects of timber, and mainly the time-to-failure (TTF), are investigated numerous times in the past, and are now fairly well understood. The time-to-failure of connections is investigated mainly for joints parallel to the grain. Comparison of these connections and timber shows a rather similar TTF behaviour. Only a limited number of investigations are known that address the TTF effects of timber loaded perpendicular to the grain by connections with dowel-type fasteners, where splitting cracks are the primary cause of failure. From this it follows that the timeto-failure behaviour is more severe for these types of connections. The same applies for variations in temperature and relative humidity of the test environment. This paper describes duration of load tests on the splitting strength of timber loaded perpendicular to the grain by dowel-type connections, where the connections have introduced high stress levels since late 2006

Splitting behaviour of timber loaded perpendicular to the grain by dowel type fasteners

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