Timber Engineering

Earthquake resistant timber structures for multi-storey buildings
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The project having been part of the National Research Programme NRP66 “Resource Wood” focused 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 was optimized for the low to medium seismicity and the moderate wind action prevailing in Switzerland. The project was carried out in a collaboration with EPFL and heig-VD.

 

 

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.

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

Contact: Dr. René Steiger

Glued laminated timber made of 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

Slabs made of cross-laminated timber panels in composite action with non-reinforced concrete
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The project’s aim was 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 were 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 were 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.

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

Contact: Dr. René Steiger