Two metal bellows seals are used to seal fluid in the damper. The London Millennium Bridge had this happen back in 2000, (check out the video below); after this incident dampers were added to the bridge. The white disk is not part of the damper. • 700-ton steel/aluminum When the Millennium Footbridge opened to the public on June 10, 2000, it was the first new bridge across the River Thames in historic London in more than a century. The dampers must continuously cycle at an average frequency of 0.8 Hz. The London Millennium Footbridge has an unusual low-slung suspension design, supported by steel cables anchored to piers on the opposite river banks. Just before the Millennium Bridge in London was re-opened,18 months after it closed due to excessive wobbling. ミレニアム・ブリッジの閉鎖中尾政之、失敗知識データベース Millennium Bridge - Structurae Arup's Millennium Bridge site A PDF paper from Arup, discussing the engineering and resonance of the bridge. It is owned and maintained by Bridge House Estates, a charitable trust overseen by the City of London Corporation. Browse the most current issue of Design World and back issues in an easy to use high quality format. Detail of dampers added to Millennium Bridge to prevent wobble Piano mechanism - hammers, felts, action, dampers of Steinway upright piano, 1909 Internal dampers of a piano Dynamite Blasting under Water. The London Millennium Footbridge across the River Thames, for example, opened with great fanfare in 2000, only to close within days after large crowds found the bridge rocking unnervingly as they walked. To assure a high resolution output, all damper attachment clevises were fabricated with fitted spherical bearings and fitted mounting pins, such that zero net end play existed in the attachment brackets. The dampers are located outdoors, over a brackish waterway with tidal flows. The tests proved to be anticlimactic—the bridge behavior being generally described as “rock solid” by the crowd. This equates to more than 109 cycles of life, far in excess of normal values for any sort of conventional damping device. Damping was eventually chosen as the preferred solution. No observable biodynamic feedback occurred. Nearly 100,000 people used the new bridge in its first day of opera tion. The metal bellows and other moving parts were constructed from stainless steel for corrosion resistance. The Millennium Bridge, officially known as the London Millennium Footbridge, is a steel suspension bridge for pedestrians crossing the River Thames in London, linking Bankside with the City of London. Here’s How, How and Why You Should Use a Wave Spring for Bearing Preload. Millennium Bridge is a suspension bridge, pedestrian bridge (footbridge) and steel bridge that was built from 1996 until 2000. What was unique about the Millennium Bridge was that resonance was occurring without any expected forced motion or marching. Seemingly random pedestrian footfalls were causing resonance of the bridge deck, with lateral accelerations measuring up to 0.25 g. The phenomena of forced harmonic excitation of bridge structures is well understood, and has been well documented by many sources. The project is located in City of London and Southwark, London, England, United Kingdom. The modifications involved the installation of a series of dampers designed to reduce the movement of the bridge to acceptable levels. The bridge opened on 10 June 2000. The Millennium Bridge reopened in 2002 after engineers fitted it with 91 dampers to absorb both lateral and vertical oscillations. Contact us today for more information. Thus, if a simple first order system with 0.5% critical damping is excited by forced resonance, the magnification factor is: If damping in the system is elevated to 20% critical, then the magnification substantially reduces to: The damping devices used on the bridge resulted in five major design issues, some of which are unique to this particular structure. The Millennium Bridge has reopened to the public, after a £5m repair programme. The Millennium Bridge, officially known as the London Millennium Footbridge, is a steel suspension bridge for pedestrians crossing the River Thames in London, England, linking Bankside with the City.It is located between Southwark Bridge (downstream) and Blackfriars Railway Bridge (upstream). On June 12, 2000, the Millennium … For a while, some even regretted that the 70-millimetre (2.8-inch) sideways sway was quickly fixed with the invisible application of shock absorbers and tuned mass dampers. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media. The design was chosen through open competition and was won by Foster & Partners and Sir Anthony Caro with Arup. We use cookies to personalize content and ads, to provide social media features and to analyze our traffic. These dampers were specified and designed to be used for mitigating the dynamic response of the bridge due to pedestrian traffic. Because hydrodynamic bushings are used, no sliding contact with the piston rod occurs, assuring frictionless performance. The lateral damping for the Millennium Bridge is provided primarily by fluid viscous dampers. These high interferences in turn generate high seal friction, accentuating the “stick-slip” motion. The design life was such that all major operating elements of the dampers needed to be constructed from inherently corrosion resistant metals that would not degrade over time. As this University of Cambridge article on the design states, "as a result [of the added 37 linear viscous dampers and over 50 tuned mass vibration absorbers] this bridge is now probably the most complex passively-damped structure in the world. Dampers on the Millennium Bridge in London. Millennium Bridge in London, United Kingdom. When opened in 2000, it was found that low-frequency lateral vibrations were excited by pedestrians. These dampers were specified and These dampers were specified and designed to be used for mitigating the dynamic response of the bridge due to pedestrian The bridge remained closed for almost two years while dampers were installed. Adapting this basic design to the Millennium Bridge involved simply scaling the small satellite dampers to the required size range. Taylor Devices, a manufacturer of damping products, proposed a unique solution, a damper that was previously used exclusively by NASA and other U.S. Government agencies for space-based optical systems. We also share information about your use of our site with our social media, advertising and analytics partners who may combine it with other information that you’ve provided to them or that they’ve collected from your use of their services. But a mere two days later, it was ordered closed due to hazardous deck motions. After extensive review of available video footage during the period the bridge was open, a series of tests identified a unique biodynamic feedback phenomena, “synchronous lateral footfall,” which resulted in seemingly random walking motions becoming synchronized over time among members of an unrelated group of people on the bridge. The Millennium Footbridge was ope ned to the public on June 10, 2000 B the first new bridge across the River Thames in historic London in more than a century. attaching additional dampers to the structure. the Millennium Bridge. The volume displaced by the compressing bellows passes through the crossover ports to the extending bellows at the opposite end of the damper. These previous applications had similar requirements for long life and high resolution at low amplitudes, but required relatively low damper forces from small, lightweight design envelopes. 座標: 北緯51度30分37秒 西経0度05分54秒 / 北緯51.510173度 西経0.098438639度 / 51.510173; -0.098438639, ロンドン・ミレニアム歩道橋(London Millennium Footbridge)はミレニアム橋の愛称で親しまれている、ロンドンのテムズ川にかかる歩道橋。2000年6月に完成した。, 歩道橋はイギリスのミレニアムプロジェクト(2000年記念事業)[注 1]のひとつとして1996年にサザーク議会によるコンペの結果、アラップ、フォスター・アンド・パートナーズ、アンソニー・カロによる設計案が当選した。, 建設は1998年後半に起工、歩道橋部分は1999年4月28日に着工した[1]。建設費は1820万ポンドで、ミレニアム委員会とロンドン信託により支払った[2]。2000年6月10日に開通したものの大きな横揺れの発生により2日後に閉鎖、対策工事を経て2002年2月22日に再開通となった。, 同歩道橋はサザーク橋(下流)とブラックフライアーズ鉄道橋(上流)との間に位置しており、南側には、グローブ座、バンク・サイド・ギャラリー、テート・モダン、北側にはセント・ポール大聖堂がある。最寄りのロンドン地下鉄の駅は、マンション・ハウス駅である。, 2000年6月10日の開通当日は、橋に隣接するテート・モダンの人気も手伝い大勢の歩行者が訪れた。しかし、人々が橋を歩き始めると、橋は小刻みに大きな横揺れを始めた。開通日の午後以降は通行人数を制限する対応がとられたが、6月12日に対策工事を行うため一時閉鎖となった。, この橋は幅の狭い吊り橋であり、多少の揺れは予測されていた。また開通日は風の強い日だった。しかし、これらを勘案しても実際に生じた揺れは想定を上回る大きなものだった。調査の結果、次のような原因で揺れが生じたことが判明した。まず、人間は人混みを歩くときに他人との衝突を避けるために無意識に他人の歩調に合わせる心理があり、歩行による荷重は分散せずに周期的なものとなった。そして橋の固有振動周期が荷重の周期に近かったため、共振により揺れ始めた。さらに、ひとたび橋が揺れ始めると、多くの歩行者が揺れに対応しようとして橋の振動に歩調を合わせるようになり、ますます橋の揺れが激しくなった[3]。, 対策として、橋の振動数を制御して共振を起こりにくくするためにダンパーを追加する工事を行った[3]。補修工事には500万ポンドを要し[3]、2002年2月22日に再開通した。, Millennium Commission(千年紀組織委員会)が主導して多くの記念イベントの開催や記念建造物が造られている。事業費用の一部はナショナル・ロッタリー(, Life: The Observer Magazine - A celebration of 500 years of British Art - 19th March 2000, Brooklyn Bridge: lateral S-shaped vibration = pedestrian oscillations or "sway". 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