變斷面TLCD抗風減震系統之試驗與分析

Abstract

本研究主要針對變斷面調諧水柱消能系統(Variable Tuned Liquid Column Damper, VTLCD)系統進行理論分析與參數研究，並實際製作一組VTLCD模型進行元件測試與結構減振之性能測試(振動台試驗)，俾便充份掌握VTLCD元件之設計參數及評估其減振效益。此外，本研究亦針對氣密式TLCD系統應用於結構防震的可行性進行探討，瞭解密閉氣室之初始壓力對於結構減震效能的影響。 根據本文之分析與試驗結果顯示，三種不同孔口板開孔面積比( )之VTLCD共振簡諧擾動試驗均有良好的減振效果，且水平段長度比採用β=0.54時有最佳之減振效果。簡諧波擾動試驗之頻率比為 時，VTLCD系統之減振效果最佳，惟擾動頻率比 時，結構振動反應則有放大的現象。此外，根據試驗資料系統識別分析所得之水頭損失係數進行非線性數值模擬，其結果與試驗結果十分契合，驗證本文所提非線性理論分析模式之合理性及精確性。氣密式TLCD應用於結構防震具可行性，於相同質量比及孔口板開孔面積比之下，水平段長度比β愈長者，減振效果愈好。最後，本文並針對世界第一高樓「台北101大樓」進行抗風減振性能評估，考慮結構水平向及扭轉向之振動控制，證明TLCD系統可有效降低其水平向及扭轉向之振動反應。偏心距愈大，TLCD系統對於結構扭轉反應之減振效果愈顯著，且減振效果隨TLCD與結構質心之距離增加之增大。

This thesis explores the theoretical analysis and parametric studies of VTLCD systems with a series of component test and performance test (by shaking table) of a prototype VTLCD system conducted to get more insight of the optimum design of VTLCD systems and its control efficiency. Moreover, the feasibility of using airtight TLCD systems for earthquake resistance of the structure is also investigated in this study. The effect of initial pressure in the air chamber of the airtight TLCD on seismic control performance is realized. According to the analytical and experimental results under harmonic excitation, the VTLCD is proved effective in vibration control with various opening ratio ( ) of the orifice considered, and the control efficiency is best as the horizontal length ratio β is 0.54. The control efficiency of VTLCD system in harmonic excitation is best for frequency ratio of 1.0, however, the vibration may be amplified if . Moreover, simulation results based on the headloss coefficient identified by the proposed system identification scheme agree very well with the test data, verifying adequacy of the proposed analytical model. Airtight TLCD system proves to be feasible for seismic protection of structures. For the same mass ratio and opening ratio of the orifice, systems with larger β perform better. Finally, this study assesses the wind-resisting performance of TLCD on both translational and torsional vibration modes of the world’s tallest building--Taipei 101, with encouraging results achieved. The larger the eccentricity of the structure, the more pronounced the control effect of TLCD on the torsional responses, and the control efficiency increases as the TLCD pair disposes farther from the centroid of the structure.