News

We are delighted to share that our team member Jelena Galić recently participated in the workshop of the WENUS – Wood Education for Sustainable Construction project, held on 27th May 2026 in Izola, Slovenia.
The workshop brought together experts and enthusiasts working to integrate wood construction and circular economy principles into modern education. Among the highlights was a hands-on demonstration of 3D printing of timber models — a technology opening exciting new possibilities in both education and construction.
Jelena returned with valuable insights and fresh inspiration, reinforcing our commitment to green skills and digital innovation as key drivers of a more sustainable future. 
A big thank you to the organizers at InnoRenew CoE for a wonderfully organized event!
Hrvatska zaklada za znanost (Croatian Science Foundation)

We continue to deepen our understanding of timber-to-timber connections using wooden dowels while expanding our database of tested structural specimens.
This time, we tested an innovative type of DLT beams and columns in which the timber lamellae feature regularly spaced interlocking notches that enhance the stiffness of the element. As a result, the relative slip between the lamellae was significantly reduced, leading to improved composite action and a higher maximum load capacity.
We also tested conventional full cross-section beams and columns, manufactured from timber of the same quality, as a control group. These tests will provide valuable insight into how our innovative DLT elements perform compared with the solid timber elements commonly used in industry.
Tests were run in the laboratory of Faculty of Civil Engineering, Osijek
Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors)

The performance of timber joints depends on both the strength of the connectors and the strength of the connected members. Alongside the embedment strength of timber lamellae, the yield moment of the connectors is a key parameter in the design and analysis of timber connections.
As the next step in our research, we investigated the yield moment of hardwood dowels with different diameters and lengths. The results will provide valuable input for numerical modelling and contribute to the development of analytical methods for the design and calculation of such connections.
Our goal is to deepen our understanding of timber-to-timber connections using hardwood dowels as connectors and to support the advancement of efficient and sustainable timber engineering solutions.

Tests were run in the laboratory of Faculty of Civil Engineering, University of Zagreb.
Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors)

Timber structural elements are gaining increasing importance as the construction industry moves towards more sustainable and environmentally responsible building practices. The structural behavior of timber elements connected with wooden dowels is strongly influenced by the method of lamellae connection.
Our experimental research journey of DLT structural elements continues with simply supported beams. To date, several test series have been carried out, focusing on the optimization of dowel diameter, spacing, and installation method.
The experimental results show satisfying correlation with the initial analytical calculations.
Tests were run in the laboratory of Faculty of Civil Engineering, Osijek.
We thank Professors Jurko Zovkić and Damir Varevac for their valuable collaboration in conducting this research.

Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors)

Our path toward fully sustainable construction continues with the experimental investigation of DLT columns.
Columns, as fundamental linear structural elements, are widely used in structural design. To ensure viability of DLT in the industry, design guidelines must be clear, reliable, and easy to apply.
The tested columns differed in their lamella connection parameters, which had a significant influence on their structural behavior and ultimate load capacity. DLT columns are presented as a promising structural solution, offering considerably greater flexibility in cross-sectional design compared to solid timber members.
Further experimental studies will focus on quantifying the influence of individual lamella connection parameters.
Tests were run in the laboratory of Faculty of Civil Engineering, Osijek.

Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors)

When designing timber structures with wooden fasteners, a deep understanding of fastener behaviour is essential. For this reason, our work begins with experimental investigation of the embedment strenght in connections with wooden dowels.
Since Eurocode 5 does not provide specific design rules for connections of timber elements with wooden dowels, it is necessary to develop correction formulas based on existing guidelines for connections using metal fasteners.
The data obtained through this research will be highly valuable for the calculation and numerical modelling of timber beam and plate elements in the years to come.
Tests were run in the laboratory of Faculty of Civil Engineering, University of Zagreb.

The accompanying video is available on our LinkedIn page: https://www.linkedin.com/posts/eco-wood-structures_circual-reduce-reuse-ugcPost-7419345726284988417-BEU6?utm_source=share&utm_medium=member_desktop&rcm=ACoAAEqvFbsBpTNX7pwRuUrCdltpOvFlBK-9ziQ.

Detailed results and analysis can be found in our article published in the Forests MDPI: https://lnkd.in/dF_FcJc2.

Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors)

In the year 2024 we tested DLT beams, DLT plates and bearing capacity of "welded" and normal dowels. The main tests were run in the laboratories of Faculty of Civil Engineering, University of Zagreb and Faculty of Civil Engineering, Osijek.

Tests were made according to EN 408 standards for beams and plates and EN 26891 (or ISO 6891) for dowels.

Video of welding process : https://lnkd.in/dw5dMB4H
Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors

We have successfully completed all planned tests for this year. We are glad that we were able to present the project to a large number of listeners who had attended the workshop. Thanks Hrvatska zaklada za znanost (Croatian Science Foundation) for support! hashtag#circular hashtag#dissembly hashtag#decarbonization

Thanks to Rothoblaas, all the speakers (Franc Weingerl and Matteo Andreottola – Rothoblaas, Prof.Vlatka Rajcic, Jure Barbalić, dr. sc. Nikola Perković – Faculty of Civil Engineering, University of Zagreb, Jure Jančar -  @CBD d.o.o. Slovenia and Dario Šišak Veda Art Studio, Zagreb),  attendees and the Hrvatska komora inženjera građevinarstva (Croatian Chamber for Civil Engineers)  for coorganization of the excellent seminar on modern timber design. We had many more people interested from Croatia, Serbia, Slovenia and Bosnia and Herzegovina than available seats. If you miss it, don't worry. Similar is planned to be organized again.

In the afternoon session we presented our Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors with the discussion focused on the fully circular economy concept in building sector: decarbonization,  and  the  Design for Disassembly approach. New regulations as Bojan Milovanović and Ivana Carević informed us, will be implemented with very high demands for energy efficiency, decarbonization, indoor quality, airtightness, soundproof  and we must be prepared.

Review with a time delay:

I am glad that at the World Conference on Earthquake Engineering (WCEE2024) held in July 2024 , Milan, Italy,  timber as a material for new structures as well as a material for rehabilitation, strengthening and upgrading of existing structures was presented very well.

Thank you, Angelo Aloisio, Roberto Tomasi, Ivan Giongo, for inviting me to present the work of our team. But also Daniele Casagrande, Massimo Fragiacomo, Martina Sciomenta and others for the efforts.

I had two presentations:

1.“Use of a timber in post earthquake reconstruction in Croatia – case studies”, where I presented several post earthquake design projects done by the Chair for Timber structures Faculty of Civil Engineering Zagreb (with my colleagues Jure Barbalić and Nikola Perković) at the session ASR-2: Timber based seismic retrofitting system for existing structures.

2. “ Introduction to the work of CEN/TC 250/SC 5/WG12/ “Assessment and retrofitting of the timber existing structures”  where I presented as a convener current plans of the newly formed working group WG12 at the session ASR-8: Use of timber for the sustainable earthquake protection of existing buildings.

The incorporation of timber into new and existing structures is a notable advancement towards creating a more environmentally friendly and durable built environment.

Also, the conference was a great opportunity to meet colleagues from all over the world dealing with similar research in timber structures to exchange ideas and the results of our Hrvatska zaklada za znanost (Croatian Science Foundation) project ECO-WOOD Structures Without Adhesives and Metal Connectors.

Fully Sustainable Timber Structures Elements Without Adhesives and Metal Connectors - ECO-WOOD Structures
Hrvatska zaklada za znanost (Croatian Science Foundation)
Research Project IP-2022-10-1800

a Project Kickoff Meeting - 15th January 2024

Project Leader:
Prof. Vlatka Rajcic

Project Partners and Researchers:
Faculty of Civil Engineering, University of Zagreb
- Assoc. Prof. Ivan Duvnjak ; Assoc. Prof. Bojan Milovanović ; Post. Doc. Nikola Perković, PhD ; Exp. Assoc. Ivana Carević, PhD ; Exp. Assoc. Jure Barbalić
Faculty of Forestry and Wood Technology, University of Zagreb
- Assoc. Prof. Ivica Župčić ; Exp. Assoc. Ivan Žulj
Josip Juraj Strossmayer University of Osijek, Faculty of Civil Engineering and Architecture Osijek
- Prof. Damir Varevac ; Asst. Prof. Jurko Zovkić
LTM Ltd
- Tomislav Skušić
TalTech – Tallinn University of Technology
- Assoc. Prof. Alar Just ; Sr. Lect. Eero Tuhkanen, PhD
Czech Technical University in Prague, University Centre for Energy Efficient Buildings
- Assoc. Prof. Petr Kuklik ; Post.Doc. Jan Pošta, PhD ; Post. Doc. Martin Hataj, PhD
hashtag#sustainable hashtag#timberstructures hashtag#ecowoodstructures hashtag#croatiansciencefoundation