Long-term mechanical behavior of dowel connections in timber structures as the basis for an extended service life and reuse

The project aims at gaining more knowledge on the long-term behavior of dowel connections, as the key factor for an efficient connection design and as basis for an extended service life and reuse of timber structures, to foster a more sustainable built environment.

This is achieved by a combined experimental-numerical study, which aims at developing a modeling tool for enhanced design rules for connections in timber structures.Experiments on the smallest meaningful length-scale for connection tests, namely the embedment scale, serve as input to the corresponding models developed in this project.

Static embedment tests provide the short-term capacity, and serve as reference for the long-term tests.

The long-term tests will be performed in constant ambient climate, for different load levels to investigate the creep behavior, and in variable ambient climate to study the effects of mechano-sorption. This information is used for development of new creep laws for the different loading directions.

In parallel, a moisture transport model based on the hybrid mixture theory will be developed to give access to the moisture distribution inside the timber cross-section, which will be linked with the mechanical and creep properties.

This information, together with results from cyclic tests, are then used as input to a so-called beam-on-foundation model, to model the long-term single-dowel connection stiffness and capacity, which will be validated by connection experiments.