On May 20th, 2010, authorities closed the Volgograd Bridge to all motor traffic due to strong oscillations caused by windy conditions. Volgograd Bridge is a concrete girder bridge over the Volga River in the city of Volgograd, Russia. The bridge and adjacent flyovers are 2,514 m long. The bridge, which was inaugurated October 10, 2009 after 13 years of construction, is a key part of a planned 30 km highway route that also includes a future bridge over the Akhtuba River.
The bridge remained closed while it was inspected for damage until the morning of May 25. It was then reopened for public access. To suppress the oscillations of the bridge, semi-active tuned mass dampers were developed and implemented by the German company Maurer Söhne in collaboration with the Swiss Federal Laboratories Empa and mutually with the University of the German Federal Armed Forces.The concept of the semi-active tuned mass dampers was proposed and laboratory validated at the Swiss Federal Laboratories Empa by Dr. Felix Weber (Empa) and Dr. Marcin Maślanka (AGH University of Science and Technology).
According to meteorological data, average speeds between 11.6 m/s and 15.6 m/s were recorded with a direction deviated seven degrees from the normal direction to the longitudinal axis of the bridge. This suggested that it could be an episode of vertical vortex induced vibrations; there are other conditions surrounding the phenomenon that lead to the same hypothesis:
- Relatively low average wind speeds and constant regime with little turbulence, caused bythe orography. The great width of the Volga River helps direct the wind along the smoothsurface provided by the water.
- The oscillation frequency coincides with the fundamental frequency of vertical vibrationof the bridge, indicating that there was a phenomenon of resonance or coupling betweenthese frequencies associated to the vortex shedding.
- The amplitudes of vibration were limited (not exceeding one meter) according to the observations made by people who witnessed the phenomenon. The image recordings made during the development of the phenomenon were used to estimate the vibration amplitudes more accurately, reaching around 65-70 cm.
The regular vortex shedding behind bridge decks placed in a flow induces periodic cross wind lift forces which can set the bridge decks into resonant vibrations if vortex-shedding frequency coincides with one of natural frequencies of the bridge. The vortex shedding frequency of the flow is generally proportional to the wind velocity as described by the Strouhal number St = fD/U. Once the bridge decks are set into resonant vibrations, the vortex- shedding frequency of the flow becomes locked onto the vibration frequency of bridge decks such that vortex-induced vibrations sus- tain over a range of wind velocity. Typically, a suspension bridge is very flexible and has closely-spaced bending modes in vertical direction.
Abraham S. Corriols and friends was investigation from his research with wind tunnel model test. The research from wind tunnel sectional model tests confirmed that the oscillations suffered by the Volgograd Bridge were due to a problem of aerodynamic resonance, and it was decided to place three sets of dynamic dampers in its three main spans. Technical work began in mid-summer 2011 and was completed in October. The total cost was about 112 million roubles (3.8 billion US dollars), accounting for 4.5% of total budget of the bridge (2,500 million roubles, 84 million US dollars).
Source: Computational analysis of VIV observed on existing bridges ; Abraham S. Corriols a, Guido Morgenthal; the Seventh International Colloquium on Bluff Body Aerodynamics and Applications (BBAA7)
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