含摩擦阻尼器外伸臂結構耐震性能研究

Shaking table test of damped-outrigger structure incorporating friction dampers

10.6849/SE.202309_38(3).0002

陳旻靖(Ming-Ching Chen)；鍾孟霖(Meng-Lin Chung)；林保均(Pao-Chun Lin )

外伸臂 ； 大型實驗 ； 摩擦阻尼 ； 數值分析 ； 鋼結構

結構工程

38卷3期（2023 / 09 / 01）

34 - 55

繁體中文;英文

此研究目的為探討摩擦阻尼器外伸臂結構系統之最佳化分析及耐震性能研究，為驗證數值分析之可靠性，設計縮尺試體進行振動台測試，縮尺試體主要分為10層，總樓高9公尺，總重量約15tonf，於實驗前透過OpenSees進行數值模型的建立，進行多模態之非線性反應譜分析探討10種不同外伸臂高程及6種摩擦阻尼器正向力之模態週期、模態等效質量。反應譜分析考慮摩擦阻尼器滑動時造成等效阻尼比增加的反應折減，迭代出結構物之最大變形。利用SRSS方法將各模態反應進行疊加，以探討最大側向變形、層間側位移角、外周柱軸力、傾覆彎矩及等效阻尼比之影響，並透過反應譜分析選擇振動台之外伸臂高程位置及摩擦阻尼器正向力。為更加準確掌握摩擦阻尼器之行為及摩擦係數，另外設計一組摩擦阻尼器進行鋼板之反覆加載測試，以不銹鋼304作為摩擦材料，阻尼器具有兩個摩擦面，以螺栓作為正向力加載來源，並透過荷重計觀察正向力變化。試驗以不同頻率及不同位移進行反覆加載，從實驗中得出摩擦係數對於溫度及加載頻率的影響極小。振動台實驗選用5個地震，分別為BCJL2、El Centro、Imperial Valley、Tabas及ChiChi，最大地表加速度為0.64g，藉由改變外伸臂高程（RF、8F及6F）及摩擦阻尼器正向力（5kN、10kN及20kN）探討含摩擦阻尼器之耐震性能。結果顯示，反應譜分析之結果與實驗結果趨勢接近，並根據振動台環境及試驗實際配置修正數值模型，分別對五個地震進行非線性動力歷時分析，探討3種不同外伸臂位置下之頂層位移、層間側位移角、外周柱軸力及核心柱底彎矩之影響，以及3種不同摩擦阻尼器正向力下的摩擦阻尼器消能表現。比較反應譜分析、動力歷時分析及振動台試驗之趨勢，探討含摩擦阻尼器外伸臂結構之受震特性及最佳耐震配置。

The main purpose of this study is to investigate the seismic performance of damped-outrigger system incorporating friction dampers through numerical analysis and shaking table tests. A 9 m tall steel structure specimen was designed by scaling down a 20-story benchmark model. The specimen was equally divided into ten floors and the outrigger beams together with the friction dampers can be installed in different floors. The normal force in the friction damper is adjustable so that its energy performance can be modified during the test. The seismic response of the specimen was evaluated by performing response spectral analysis (RSA) using the OpenSees numerical model. The equivalent damping ratio was included in the RSA in order to evaluate the energy dissipation resulted from the friction dampers. Based on the RSA results, the specimen configurations when outrigger locates at the sixth (6F), eighth (8F), and roof floors (RF) and when the normal force in the friction damper varies between 5 kN, 10 kN, and 20 kN were tested by imposing five different ground motions with the peak ground acceleration of 0.64g. Both the RSA and test results indicated that the maximum roof drift of the specimen was around 0.7% 0.4%, and 0.3% rad., when the outrigger locates at the RF, 8F, and 6F, respectively. The greater normal force applied in the friction damper generally result in a greater amount of energy dissipation and a smaller roof drift response. Based on the experimental and numerical results, the optimal design of the damped-outrigger system incorporating friction dampers are demonstrated in this study.

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