Talks and Poster Presentations (without Proceedings-Entry):
M. Reiterer, M.J. Hochrainer:
"DAMPING OF FOOTBRIDGE VIBRATIONS BY TUNED LIQUID COLUMN DAMPERS: A NOVEL EXPERIMENTAL MODEL SET-UP";
Poster: 21st Danubia-Adria Symposium on Experimental Methods in Solid Mechanics,
Brijuni / Pila, Croatia;
The highly publicized closure of Londonís Millenium Footbridge due to excessive lateral vibrations at its opening day in June 10, 2000 has highlighted a potentially unexpected problem in footbridge constructions. During the investigations of the Bridge a number of other instances of bridges suffering excessive lateral vibrations under crowd loading have been coming to light, e.g. the Toda Park Bridge in Japan. The following extensive retrofit of the Millenium Bridge involved the use of fluid viscous dampers and conventional tuned mass dampers (TMDs) to increase the structural damping with, finally a total cost of 10 million Euro.
In the present investigation it is proposed to apply the more efficient and more economic tuned liquid column damper (TLCD) for suppressing the pedestrian induced vibration of footbridges. The TLCD relies on the motion of a liquid mass in a sealed tube-like container to counteract the external motion, while a built in orifice plate induces turbulent damping forces that dissipate kinetic energy. For optimal tuning of the TLCD the natural frequency and equivalent linear damping coefficient have to be chosen suitable, likewise to the conventional TMD, as indicated by Den Hartog. The great advantages of TLCDs over other types of damping devices are: simple tuning of natural frequency and damping, where the damping can be controlled by the opening angel of a built in orifice plate, low cost of design and maintenance and a simple construction.
In order to study the damping effectiveness of optimal tuned TLCDs a small scale bridge model has been constructed in the laboratory of the TU-Institute
Created from the Publication Database of the Vienna University of Technology.