強健式調諧質量阻尼器於人行橋最佳化設計在行人荷載下其減振效果之探討

The Optimal Design of Robust Tuned Mass Damper for Footbridges and the Performance under the Pedestrian Loads

鄧啟聰(Kai-Chong Tang)

指導教授 ： 呂良正

國立臺灣大學/工學院/土木工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202102827

摘要

隨著都市的發展和科技的進步，城市人行天橋不斷向大跨、輕柔和美觀的方向發展，導致人行橋的自振頻率和阻尼亦不斷降低，其一階豎向自振頻率往往處於行人荷載步頻1.25~2.3Hz的範圍內，產生人-橋共振，輕則給行人帶來不適感和心理上的恐慌，重則可能引起結構損傷、甚至破壞，因此針對大跨人行橋開展行人荷載作用下振動舒適度分析及其減振控制研究具有重要的現實意義。目前建築已廣泛使用各種類型的阻尼器來控制振動並消能，而調諧質量阻尼器是目前常見的一種，大多用於大跨度橋樑，高層建築或是高科技廠房內的機台上，以抗振並提高舒適性。
本研究以跨度50m人行鋼橋作為主要研究對象，首先利用套裝軟體SAP2000進行有限元建模，接着採用European Research Area-European Commission的研究計劃HiVoSS(Human-induces Vibration of Steel Structures)模擬人行橋所受到的行人荷載，並以ISO 2631-2:1989規範提供的容許加速度作為控制指標去設計TMD參數。本研究考慮主系統頻率因外在因素產生變異性所發展出強健式調諧質量阻尼器之最佳化設計方法，並比較一般式TMD與強健式TMD效能優劣。此外，本研究還提出加速度均方值包絡線的概念，找出TMD所需要的最低質量比，使得橋梁中央的加速度峰值降至法規上限值，避免過度設計的同時兼顧建築物的舒適性問題。

關鍵字

調諧質量阻尼器 ； 強健式設計 ； 最佳化 ； 包絡線 ； 人行橋

並列摘要

With the development of the city and the progress of technology, urban pedestrian overpass constantly to the direction of large-span, gentle and beautiful, lead to the natural frequency and damping of the footbridge is falling, the first order vertical natural frequencies are often in a pedestrian load frequency within the range of 1.25 ~ 2.3 Hz, produce - bridge resonance, light pedestrians discomfort and psychological panic, or may cause structural damage, and even damage, so in view of the large span footbridge in pedestrian loads for vibration analysis and vibration control research has important practical significance. In recent year, a serious of dampers have been widely used to control the vibration and dissipate energy. Tuned mass dampers are common one of them. TMDs are often used in high-rise buildings, long-span bridges and machines of high-tech factory to reduce the vibration and the discomfort.
In this study, a 50m-span pedestrian steel bridge as the main research object. First, the software package SAP2000 is used for finite element modeling, and then the pedestrian load is simulated by the HiVoSS(Human-induce Vibration of Steel Structure) that is a European Research Area- European Commission’s research project. As the same time the maximum tolerable acceleration is provided by ISO 2631-2:1989 standard as the control index to design TMD parameters. In this study, we consider the external factor that can cause variability of the natural frequency to develop the optimal design method of robust tuned mass damper, and then make a comparison between the effectiveness of the general design and the robust design. Furthermore, we proposed the concept of the acceleration mean square value envelope line to find the minimum mass ratios of TMD that can make the peak accelerations on the bridge center lower than the upper limit form ISO standard. Therefore, the effectiveness of vibration reduction can be achieved, in the meantime over-design can be avoided as well.

並列關鍵字

Tuned Mass Damper ； Robust Design ； Optimization ； Envelope Line ； Footbridge

參考文獻

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