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As part of the renovation project that involved building a new stadium within the confines of the old historic building, twenty-one TMD’s were designed and applied to the upper grandstand perimeter covering almost 1000 linear feet with a total sprung weight of 840,000 pounds. This was done to reduce potential crowd induced vibrations on the west grandstand which had to be cantilevered out 40 feet beyond the column supports because of design requirements. The TMD’s are providing impressive reduction of vibration levels in the design frequency range of 1.5 Hz to 2.7 Hz and eliminate virtually all resonant peaks in the 2 Hz to 3 Hz frequency band. Vibration reduction factors are typically in the range of 3 to 10. The success of the project was based on a unique configuration of spring systems to achieve flexibility in the design and field tuning.
Believed to be the most elaborate permanent structural vibration monitoring system in the world, the 64-channel vibration monitoring system was designed to measure the performance of the TMD's, on-going maintenance and to facilitate administrative control of vibration at Soldier Field stadium in Chicago. The system which has the remote operating capability was successfully used in commissioning test of the TMD's. The system is controlled through an in-house developed software application which can be modified to perform specific tasks and record or transmit vibration data.
A single tuned mass damper was designed for a newly constructed building in Manhattan where the activities of professional dancers at the 9th floor dance studio created unacceptable floor vibration on the 10th floor offices. A shaker test with only one TMD placed on the 10th floor (in active and locked out mode) showed impressive reductions in floor vibration levels shown in the following graph. 
The State-of-the-Art of the reduction of vibration of long-span floors has been extended. TMD's were designed and applied to a very long-span floor in the Quebec Convention Centre reducing the vibration by factors of 4.5 to 7.5 for the vibration modes of concern. These vibration reduction factors significantly exceed those previously achieved. The success of he project was based on an innovative technology for the dashpots and an unusual configuration of springs/load-support to achieve flexibility in the design and field tuning. The technique is applicable to both new and existing floors where floor vibration is either anticipated or has been experienced and is much less expensive than structural changes.
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Last modified: 04/11/06 |
