Timber Engineering

OUR SERVICES
  • Mechanical testing of timber structural members and joints, proof loading of timber structures
  • Non-destructive / minimal invasive evaluation / assigning to strength classes of solid timber, glued-laminated timber and engineered wood products
  • Experimental evaluation of the mechanical properties of composite structures consisting of wood
  • Special tasks in the course of conditions surveys and condition evaluation of timber structures
  • Consulting and expert’s opinions for timber structures

 

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RESEARCH AND DEVELOPMENT

Earthquake resistant timber structures for multi-storey buildings

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The project being part of the National Research Programme NRP66 “Resource Wood” focuses on the behaviour of joints and wall elements in multi-storey wooden structures during moderate earthquakes and strong winds. Using a deformation based design method the structure shall be optimized for the low to medium seismicity and the moderate wind action prevailing in Switzerland. The project is a collaboration of EPFL, heig-VD and Empa (lead)

Funding: Swiss National Science Foundation SNSF, National Research Program NRP 66

Contact: Dr. René Steiger

On-site assessment of actual dynamic properties of a multi-storey timber building

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In order to get more detailed information on the stiffness, the fundamental frequencies and the damping ratio of multi-storey timber buildings reflecting the actual type of construction in Switzerland, the dynamic properties (horizontal deformation, resonance frequencies, damping ratio) of a 3-storey light-frame timber building with timber-concrete composite slabs were assessed experimentally on-site. Ambient and forced vibration tests of increased levels of excitation were performed in different stages of construction. The tests revealed that non-structural elements significantly impact the dynamic behaviour of the structure. Based on the test results methods to be applied in design process shall be developed on how to better predict the dynamic behaviour of such types of structures.

Funding: Empa and Federal Office for the Environment FOEN (Fonds zur Förderung der Wald- und Holzforschung)

Contact: Dr. René Steiger

Hardwood glulam made from European beech wood

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In the project collaboration of Empa, ETH Zurich and Bern University of Applied Sciences it is aimed at promoting the use of beech wood for the production of glued-laminated timber of strength classes GL40, GL48 and GL55 (if possible). Main prerequisites to be developed are appropriate production technologies, rules and processes in quality control of raw material and final product as well as mechanical properties of beech glulam in the mentioned strength classes serving as basis for design of structural elements (preferably beams and columns in service class 1). Starting from the raw material supply (origin, sawing pattern, drying process, strength grading) all further steps in production (finger jointing, surface gluing of lamellas) as well as the properties (strength and stiffness) of the final product shall be investigated.

Funding: Federal Office for the Environment FOEN (Aktionsplan Holz)

Contact: Dr. René Steiger, Dipl.-Ing. Thomas Ehrhart

Hochbau-Decken aus Brettsperrholz im Verbund mit nicht armiertem Beton

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The project’s aim is to investigate and further develop a slab system consisting of a composite cross-laminated timber / concrete cross-section. The concrete plate lacks of any rebars and the cross-lam panel acts as formwork and as tensile reinforcement simultaneously. Strength, stiffness and failure modes of beam-type elements shall be investigated in short-term and long-term bending tests. Number, positioning and shape of the shear connectors guaranteeing a rigid connection between cross-lam panel and concrete slab shall be optimized taking into account not only stresses when subjected to varying levels of bending moment but also from changes in moisture and from long-term effects as creep and shrinkage. Finally it is planned to conduct punching load tests on plate elements.

Funding: Federal Office for the Environment FOEN (Fonds zur Förderung der Wald- und Holzforschung)

Contact: Dr. René Steiger

Residual load-carrying capacity and retrofitting of glued-laminated timber with cracks

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The project is carried out in collaboration with Bern University of Applied Sciences – Architecture, Wood and Civil Engineering and aims at developing reliable methods for assessing the residual load-carrying capacity of cracked/damaged glued-laminated timber members. Delamination and cracks are major visible indicators in a first assessment of timber constructions. But how to respect these cracks observed when estimating the residual load-carrying capacity of timber structural elements with cracks? The residual load-carrying capacity of such members will be investigated and evaluated by means of numerical simulations based on existing crack situations gathered from real structures. By investigating different distributions and parameters of cracks, methods for the estimation of the residual load-carrying capacity of glulam beams with cracks and for retrofitting such elements shall be developed.

Funding: State Secretariat for Education, Research and Innovation SERI, European Cooperation in Science and Technology COST, Action FP 1101

Contact: Dr. René Steiger

Dr. René Steiger

Dr. René Steiger
Civil Engineer, Senior Research Associate

Senior Researcher

Phone: +41 58 765 4215