含變位放大阻尼效能增進機制扭轉向遲滯消能支撐之耐震行為研究

Abstract

黏彈性阻尼器為一種具有勁度、高阻尼比的被動消能控制器，可用於大幅提高結構之阻尼比，以降低在強風或地震下結構之動力反應。現今所使用的阻尼器無法直接安裝在結構物上，須藉由支撐構件來連接結構主體，然而傳統阻尼器大多採用對角或水平方式加裝於結構物上，對於高勁度、低變形的結構物來說，往往侷限了阻尼器的消能效果，為突破此限制，一種新的銜接阻尼方式因應而生-肘型斜撐(Toggle Brace)，其利用簡單幾何關係使阻尼器發揮更大的功效。 本研究主要是利用此種銜接阻尼機制並結合扭轉向黏彈性阻尼單元(Rotational visco-elastic damper,RVED)所構成的消能原件，理論部分首先從探究消能材料行為，進而衍生推導出RVED的動態力學行為，接著透過定義放大因子，從幾何觀點去了解調整肘型斜撐長度及擺放角度對扭轉向阻尼單元的影響程度，然而，利用放大因子並考慮肘型斜撐勁度與阻尼單元勁度推演出單自由度結構結合此種消能機制所能提供之阻尼比，並了解參數間對阻尼比的互制關係，最後，根據公式建立出此消能系統的制震曲線，觀察設計參數間對減震效果的影響。接著選取一座三層樓縮尺及一座九層樓實尺寸的既有構架加裝本研究所研發的消能元件，依據推導出的理論公式，調整設計參數使其達到特定阻尼比，並採用475回歸週期等級的設計地震評估加裝阻尼器前後的受震反應。分析結果顯示，本研究所探討的扭轉向消能原件具有良好的消能效果。

Energy dissipation systems are being increasingly employed in Taiwan to provide enhanced seismic protection for new and retrofit building and bridge construction. The hardware utilized includes yielding steel devices, friction devices, visco-elastic solid devices, and mostly, so far, fluid viscous devices. This hardware has been used in either diagonal or chevron brace configurations. This study presents some new configurations that utilize displacement-magnification mechanisms to substantially magnify the effect of a novel rotational hysteretic energy-dissipated device incorporating with a displacement magnification mechanism and visco-elastic materials or high-damping rubber so that it can be utilized effectively in applications of small structural drift. In this study, a toggle-brace-damper configuration with rotational visco-elastic dampers (RVED) directly installed to the beam–column joints is presented. To facilitate practical applications, a procedure for determining the relationship between the displacement magnification factor and the geometry of the toggle-brace mechanism is established. Prototype tests, and shaking table tests are conducted to investigate the seismic responses of a large scale three-story steel model structure with and without RVEDs. Structural dynamic analyses are also used to demonstrate the utility of the proposed rotational hysteretic energy-dissipated devices. And the seismic design procedure and simulation technique for buildings installed with the rotational hysteretic energy-dissipated devices would be also proposed in this plan.