Protocols and results analysis methods for cyclic tests of timber joints: a discussion

Abstract

Current testing procedures for cyclic loading are quite flexible and the influence of fundamental testing parameters on the obtained load-deformation behaviour is often questioned (number and amplitude of the loading cycles, loading rate, number of specimens, etc.). On the other hand, different methods for data assessment have been used for the definition of stiffness, ductility, strength and stiffness degradation, as well as parameters for analytical and numerical models. However, reliable and well-established assessment methods are required, to support the safe and economic design of timber joints. Fundamental parameters for seismic design, such as ductility or strength degradation, cannot depend on the testing protocol and method for assessment of the data results. In this context, it is important to compare the most representative loading protocols, and assessment methods of the test results, through detailed analysis and discussion. Different types of timber connections, made of distinct materials and tested in different laboratories, must be evaluated. This work will be developed within the RILEM TC TPT, and this paper represents a first contribution to a needed discussion about the testing protocols to evaluate timber connections. In the end, it is expected to present proposals on how to characterize better the properties and behaviour of timber connections under cyclic loading and how to fully utilize their potential in design.