由於台北101大樓為一超高層大樓,在半年回歸期之風力作用下,其頂層辦公室 (89F)加速度超過5 gal而不滿足規範規定,為解決此因風力產生大樓搖擺問題,因此加裝諧調質量阻尼器(Tuned Mass Damper或TMD)來降低結構反應,然而諧調質量阻尼器具成本高及維護不易之缺點,本文特介紹諧調液體阻尼器(Tuned Liquid Damper 或TLD)及其對台北101 大樓風力減振效果之探討。本文將台北101大樓簡化模擬成剪力剛架,應用勢流理論及邊界元素法分析圓柱形水槽之三維非線性水激盪 (sloshing) 行為,利用Lagrangian座標系統及泰勒級數之時間展開式描述自由液面變化,由柏努利公式求得槽壁動態水壓力及槽底剪力,如水槽設計適當,可作為諧調液體阻尼器之用途,此槽底剪力對大樓提供阻力,可有效控制大樓風力反應。經與TMD減振效果比較得知,TLD確具有優越的減振能力,因為TLD主要是利用水作為減振之主角,所以構造簡單、經濟實用,TLD還兼有作消防及游泳等用途,故應有實用發展之潛力,這也是本文之另一個主要目的。
The three dimensional sloshing behavior of a cylindrical water tank installed on Taipei 101 subjected to gust excitation is under investigation. The boundary element method with the Langrangian coordinate description of the free surface and the Tayor series expansion of time is employed to solve the transient velocity potential and its normal gradient on the free surface. The base shear of the tank can be evaluated from the hydrodynamic pressure on the tank wall by Bernoulli's equation. This base shear of the water tank would give a sort of resistance to the building against gust excitation, if the design of TLD is properly. The efficiency of vibrational control of TLD compared with tuned mass damper (or TMD) is also addressed. As a result, TLD is not only excellent in vibrational control, but also economic in practice, especially for high-rise buildings.