採最佳化黏滯阻尼設計公式之隔震實務設計流程

Structural Isolation Design Procedures with Optimal Viscous Damping

楊卓諺(Cho-Yen Yang) ； 王勝宣(Sheng-Hsuan Wang) ； 劉紹魁(Shao-Kuei Liu) ； 鍾立來(Lap-Loi Chung) ； 洪維良(Wei-Liang Hung) ； 陳陸民(Lu-Min Chen)

《結構工程》 30卷4期 (2015/12) Pp. 65-78

https://doi.org/10.6849/SE.201512_30(4).0003

摘要

由耐震設計中反應譜的觀念得知，當結構系統之週期較長時，有較低之設計地震力。而隔震系統乃呼應此一觀念，藉由延長結構系統之週期來降低上傳之水平地震力。而阻尼在隔震系統所扮演的角色，除了消能之外也能夠適當降低隔震層位移。由於地震震度與震波形式之不確定性，結構物於使用年限之間有可能碰到尖峰地表加速度(PGA)更甚於設計地震之非設計地震；或具有低頻特性之近斷層震波。因此，本文嘗試將本團隊所發表之黏滯阻尼最佳化設計公式融入業界習用之隔震設計流程，是為最佳化設計流程，並以設計地震、非設計地震、近斷層地震當作輸入，來探討業界習用之設計流程以及最佳化設計流程於隔震效果及隔震層位移之差異。本文分別針對設計地震力、1.5 倍設計地震力與近斷層地震力對一真實之隔震結構進行模擬分析。其結果顯示，兩種設計流程於三種外力下皆能有效降低加速度反應，但當外力為非設計地震力，即1.5 倍設計地震力與近斷層地震力時，僅最佳化設計流程能確保設計位移滿足隔震層位移反應之需求，故本設計流程實屬可行。而本設計流程相對於業界現行之設計流程僅多增加一步驟，並不會大幅影響工程師之設計習慣。再者，本設計流程已提供出隔震層阻尼之需求，可作為工程師決定阻尼之依據。

關鍵字

隔震設計流程 ； 最佳黏滯阻尼 ； 非設計地震

並列摘要

Based on the concept of seismic design spectrum, the design seismic force is smaller when a structure possesses longer fundamental period. It is the main purpose for isolation system. The damping plays a significant role with function of energy dissipation and reducing the isolation displacement. Because of the uncertainty about earthquake intensity and fault activity, the structure may encounter a non-design earthquake with greater peak ground acceleration (PGA) or a near-fault earthquake within the structural service life. For this reason, we attempted to integrate the optimal viscous damping ratio formula into the conventional design procedures, called optimized design procedures, and chose a real case to do the time history analysis and then discussed the feasibility of optimized design procedure. Three earthquake types were utilized as input, one was the design earthquake, another was a non-design earthquake with PGA which was 1.5 times the design earthquake, the other was a near-fault earthquake. Regardless of the types of input, the isolation system with optimal damping ratio can play a good result about isolation effect and displacement. Therefore, we confirm integrating the optimal damping ratio formula into the conventional procedures is essential. For engineers, there is just one more step in the optimized design procedures than the conventional one, and the requirement of damping can be determined according to the proposed procedures.

並列關鍵字

isolation design procedures ； optimal viscous damping ； non-design earthquake