結構物邊界條件模擬方式對耐震評估之影響：
以朝陽科技大學舊工程大樓為例

自1975年由Freeman提出最原型之容量震譜法，乃至1993年Mahaney等人提出及引進ADRS格式後至今，容量震譜法被大量使用於鋼筋混凝土構造之耐震評估分析上。雖國內相關研究數量可觀，但包含側向邊界條件對評估結果影響與否之文獻則有限，本論文以朝陽科技大學舊工程大樓為對象，針對含側向邊界條件與土壤束制之模型進行耐震評估影響程度探討。　　本研究將側向邊界條件之模擬分為：牆體、彈簧及固端束制三種，設定之下部邊界條件則分為：彈性基礎柱體、土壤彈簧及固定支承三種。基礎層之模擬尚須考慮土壤勁度，本論文以虛功法推導土壤彈簧勁度加載於基礎柱頂端上。結構模型搭配不同邊界條件後，分別進行側推分析，求得容量曲線，轉換至容量震譜後，選取最大譜加速度或譜位移之點，求得其對應之性能目標加速度，即為耐震能力。　　研究發現，若結構物之基礎為普通或堅硬土層，則基礎層影響極微，以固定支承模擬即可。側向邊界條件之考量與否對評估結果有相當程度之影響，且若使用固端束制，會給予結構過多之束制而不符合現實情況，較適當之模擬方式為實際牆體元素或彈簧之模擬。

關鍵字

容量震譜；邊界條件；耐震能力；耐震評估；土壤彈簧

並列摘要

Since 1975 Freeman introduced a prototype model of the capacity spectrum method, Capacity Spectrum method has been widely used in the seismic assessment of reinforced concrete. This is especially true after Mahaney and others proposed ADRS format in capacity spectrum method in 1993. Over the years, there are many related researches by domestic researchers and yet seldom addressed the effect of the boundary modeling on the evaluation results. Therefore, through the case study of old engineering building at CYUT, the aim of this work is to investigate the degree of influence due to boundary modeling on the Seismic Capacity Evaluation. In this study, the lateral boundary conditions are modeled by walls, springs, and fixed supports , while the lower part of the boundary conditions, namely the foundations, are simulated as piles (members on elastic foundation), equivalent springs with soil stiffness, and rigid connections. Push-Over analyses are first carried out for various structural models with different boundary conditions at both lateral and foundation interfaces. Capacity curves can thus be obtained and converted to capacity spectra. Finally, corresponding acceleration of Seismic capacity can be determined by finding the maximum spectral acceleration or displacement of the spectra. The major findings based on the simulation results are as follows. For structures rested on normal to hard soil, the responses are so close to those associated with fixed supports that they can be modeled as fixed structures for simplicity. On the other hand, lateral boundary conditions significantly alter the result of seismic capacity on the target structure, and thus they are required to provide appropriate results. However, the results indicate that simulations based on shear wall elements and equivalent springs are more suitable selections since models with laterally rigid supports seem leading to over-estimated capacities

並列關鍵字

boundary conditions ； soil spring ； Seismic evaluation ； Capacity spectrum ； Seismic capacity

參考文獻

【2】聯邦工程顧問股份有限公司、李森柟，ETABS入門與工程上之應用，民國93年5月。

【5】蔡益超、宋裕祺，以結構性能為目標的鋼筋混凝土橋梁耐震能力評估，中華技術雜誌NO.58, April, 2003.

【17】李錫霖、張奇偉，既有鋼筋混凝土建築物耐震評估與補強設計之探討，第五屆中日建築結構技術交流會，民國90年6月，中國，西安。

【4】蔡益超、陳清泉，鋼筋混凝土建築物耐震能力評估法及推廣，內政部建築研究所專題研究計劃成果報告，GPN：002244880240，民國88年。

【10】Liao, S. T.,”Nondestructive Testing of Piles”, Ph. D. Dissertation, Department of Civil Engineering, University of Texas, Austin, Texas, 1994.

國際替代計量

結構物邊界條件模擬方式對耐震評估之影響：以朝陽科技大學舊工程大樓為例

主題瀏覽