Static and Dynamics of Structures

OUR SERVICES
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Large scale static loading tests

The unit for Structural Engineering offers experts from the construction and mechanical engineering field the possibility to carry out large scale static test on our strong floor (18 m x 40 m). In addition to force measurements and conventional displacement and strain recording by means of LVDTs and strain gauges, new innovative technique such as full-field image correlation systems can also be offered. The long experience of our team combined with an excellent laboratory equipment guarantee excellent testing conditions.

  • In-Situ monitoring and load testing of structures for the verification of calculated characteristics.
  • Determination of the elastic constants of anisotropic materials.

Contact: Dr. Glauco Feltrin,  Dr. Christoph Czaderski,

RESEARCH AND DEVELOPMENT
Updated braking forces for the assessment of road bridges
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Since 1956 the braking forces in the Swiss codes have significantly increased (0 kN in 1956, up to 900 kN in 2003). Because of this development, most of the existing bridges in Switzerland have been designed for braking forces that are much smaller than the provisions of the current codes, which are based on a deterministic model. Therefore, it is very likely that a significant number of bridges shows a nominally insufficient structural safety. Using a stochastic traffic flow model, an empirically founded model for simulating the braking of heavy vehicles on bridges shall be developed.


Funding: ASTRA, Arbeitsgruppe Brückenforschung
Contact: Dr. Glauco Feltrin, João Martins

Influence of mastic-asphalt pavement on natural frequencies and modal dampings of timber footbridges

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Timber bridges with decks made of laminated solid timber panels are often protected against mechanical abrasion and humidity with a mastic asphalt pavement. Measurements performed on a footbridge demonstrated that the bond between panel and pavement may produce significant temperature induced changes of natural frequencies and modal dampings.

 


Funding: Fonds zur Förderung der Wald- und Holzforschung
Contact: Dr. Glauco Feltrin, Dr. René Steiger, Dr. Benedikt Weber

Influence of the asphalt pavement on the dynamics of footbridges made of concrete and steel
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The asphalt pavement influences natural frequencies and damping of footbridges. This influence is due to the bonding between the bridge deck and the asphalt pavement and strong temperature effect on the mechanical properties of the asphalt. The project investigates experimentally how large the changes of natural frequencies and modal dampings are and how reliable numerical models allow predicting these changes.

 


Funding: ASTRA, Arbeitsgruppe Brückenforschung
Contact: Dr. Glauco Feltrin, Dr. Benedikt Weber

Temperature effect on tuned mass dampers for footbridges
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Tests with a shaker were performed on two footbridges with tuned mass dampers. The parameters of the tuned mass dampers were computed using a system identification method. The results demonstrated that temperature has a significant effect on the natural frequency and damping of the tuned mass dampers. This effect limits in practical applications the accuracy of optimal tuning and the effectiveness of tuned mass dampers.

 


Link to article reference (RefShare)
Contact: Dr. Benedikt Weber, Dr. Glauco Feltrin

Large Scale Testing with full Field Deformation Measurement

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Contactless surface covering measurements are more and more frequently used in civil engineering for tests on construction units and in research at Empa.
The disadvantages of punctual measurements with strain gauges, mechanical displacement sensors may be avoided. The measuring results deliver the shape of the specimen surface and full field ditributions of strains and displacements in three orthogonal directions.

Contact: Dr. Christoph Czaderski

Cyclic static behaviour of gypsum panel and steel stud walls

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Walls made of cold-formed steel sections with gypsum panels (wallboard) are a sucessful residential construction method in North America, and their use has seen steady growth in Australia and parts of Europe. In the past, these types of walls have most commenly been used as non-structural partitions. A goal of this investigation is to better understand and improve their load-carrying and deformation capacity when subjected to cyclic static horizontal displacements.

 

Contact: Dr. Benedikt Weber

Smart cable-stayed bridge - a research platform

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In today’s bridge design, a trend towards longer spans as well as more slender structures and structural elements is observed. As a consequence, modern bridges are becoming increasingly prone to vibrations. In order to avoid dynamic problems, the development of appropriate vibration mitigation methods and health monitoring systems has become essential.


Contact: Prof. Dr. Masoud Motavalli