Connections in Timber Structures
Connections in Timber Structures is one of the research fields at the Department of Building Technology. We investigate the mechanical behaviour of connections at different length scales, from local dowels up to large joints for timber structures. Based on the outcomes, we develop computational simulations and propose design recommendations.
Every timber structure includes connections of some kind. Connections link the single timber members with each other, transferring the loads from one element to the next. Due to their complex force and deformation behavior, connections are key elements in the design of timber structures, especially when building wide spanning and high rising structures. It is of highest importance to make connections as efficient as possible to allow for competitive design of timber structures.
Over many years, comprehensive knowledge in experimental and numerical research on connections in timber structures has been built up at Linnaeus University. In various projects, we investigate the mechanical behavior of connections at different length scales from the local embedment behavior of dowels up to large joints for timber structures. This includes a large range of wood-based materials, connectors and connection types. Based on the research outcomes, we develop computational simulations and propose design recommendations for exploiting the knowledge in the calculation and design of timber structures.
Wood interface to the connectors
Due to the inherent anisotropic mechanical nature of wood and wood products, a complex stress state in the wood below the interface with the connectors is evoked. This makes numerical modeling of these local effects very challenging.
To develop a thorough understanding of the complex mechanical behaviour of the wood interface to the connectors, we carry out a large range of experimental studies at the Department of Building Technology at Linnaeus University. Embedment test of steel dowels in wood and wood products, loaded under various angles to the fiber direction of wood, can be named as one example. Results from these tests are a valuable input to numerical tests on the single-fastener connection scale, as well as for standardization.
The diversity of connection types in timber structures seems to be sheer endless, which makes it cumbersome to investigate all of them by experiments. Thus, at Linnaeus University, we utilise and enhance numerical models for predicting the mechanical behavior of single-fastener connections since more than a decade.
We develop numerical models of different complexity, from advanced scientific models to engineering approaches. These models are validated by comparison of their predictions with experiments, using our unique testing facilities of the in-house laboratory. We especially aim to make our research accessible to our industry partners and the timber engineer community in general, by participating in international platforms to further develop timber engineering design standards.
Based on a profound knowledge of the single-fastener behavior, we can use numerical models of different complexity to predict the behavior of the entire joint. We apply these models to different types of joints and experimentally validate them, ranging from moment-loaded dowel connections to nailed connections of OSB-sheathing in timber frame structures. These examples highlight the versatile application spectrum of our numerical models.
Joints in timber structures
We then further exploit our numerical connection models, supported by experimental investigations, by applying them in the analysis of timber structures, in order to study their global behavior and load distribution. Other application examples are timber-framed shear walls and prefabricated timber modules.
Doctoral project: Connections and compression perpendicular to the grain in cross-laminated timber The main aim of the project is to predict in a combined experimental-numerical study the mechanical…
Project: Competitive timber structures – Resource efficiency and climate benefits along the wood value chain through engineering design Through increasing scientific knowledge along the wood…
Project: Compression perpendicular to the grain in cross-laminated engineered wood-based products The aim of this project was a better prediction and exploitation of the properties of wood in…
Project: ForestValue Hardwood joint - Innovative joints in hardwoods The overall project objective is to foster high-performance hardwood structures in the European building sector by developing…
Project: Improving the competitive advantage of CLT-based building systems through engineering design and reduced carbon footprint The objective of this project is to increase the competitiveness of…
Project: 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…
- Anders Alrutz Research engineer
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- Carl Larsson Doctoral student
- Joan Gikonyo Research assistant
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- Le Kuai Research assistant
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- Michael Dorn Associate Professor
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- Michael Schweigler Senior lecturer
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- Sigurdur Ormarsson Professor
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- Thomas K Bader Professor, Head of Department
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