間接接合型鋼框架斜撐在RC構架之耐震補強研究

Study of Steel Frame Bracing System with Indirect Connection on Seismic Retrofitting of RC Frame

簡巧涵(Qiao-Han Jian)

指導教授 ： 黃世建

國立臺灣大學/工學院/土木工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.00165

摘要

目前國內對既有建築物之補強相當關注，本研究針對間接接合型鋼框架斜撐補強工法進行探討，建議一套有效的設計方法提供工程師參考，希望補強後構架不僅增加垂直承載力及側力強度，亦能發展良好之變形能力，達成80%最大側推強度時，層間變位角2%以上之目標。
本年度研究著重於接合部之詳細設計，參考ACI 318-14之錨栓設計公式與HILTI固定設計手冊，進行接合部強度評估，並參考日本接合部斷面配置，最後建議了一套設計步驟，進而設計試體M16及M20進行實驗驗證。
實驗結果發現，相同層間變位角下，螺旋箍筋部分砂漿剝落嚴重，而矩形箍筋部分砂漿仍維持良好，比較可惜的是本次試驗接合部發生非預期破壞，剪力釘剪斷於銲接部分，使力量集中於角落砂漿，為避免此種破壞模式，建議剪力釘配置應進行改善。試體M16及M20斜撐皆挫屈使構架發揮良好韌性，試體M16補強倍率5倍，80%最大強度時層間變位角達3.7%，試體M20補強倍率7倍，80%最大強度時層間變位角達1.88%，結論本研究建議之設計步驟，能有效評估間接接合型鋼框架斜撐補強工法之補強效率，並達成變形能力目標。

關鍵字

耐震補強 ； 鋼筋混凝土構架 ； 鋼框架斜撐 ； 隅板 ； 補強接合部 ； 變形能力

並列摘要

Nowadays, Taiwan has been working on researches of seismic retrofitting on existing reinforced concrete buildings. This study focuses on the retrofitting method of using steel frame bracing system with indirect connection, and suggests an effective design procedure for engineers to use. It is expected that this retrofitting method can help existing RC buildings not only increasing vertical bearing capacity and lateral strength, but also developing good deformation ability which is defined as drift ratio develop higher than 2% when 80% of maximum lateral force happened.
This study focuses on the design detailing of mortar connection between steel bracing system and RC frame. The strength of mortar connection is evaluated by using design equations of anchors from ACI 318-14 and HILTI design manual. The configuration of mortar connection refers to design manual of Japan. Gathering all the design requirements, we suggest a design procedure and design specimen M16 and M20 to check the usability of proposed design method.
According to the observation from test results, at same drift ratio, mortar in the connection with spiral spalled dramatically while that with square stirrups remained well. Unfortunately, an unexpected failure, which is that studs in the connection had split at weld, made the stress concentration happened at corner mortar. To avoid this kind of failure mode, we suggest that the arrangement of studs needs to be improved. Specimens, M16 and M20, have developed good ductility due to brace buckling. Specimen M16’s deformation capacity is 3.7% with the retrofitting ratio of 5, while Specimen M20’s deformation capacity is 1.88% with the retrofitting ratio of 7. In conclusion, the proposed design method can not only help engineers effectively assess the retrofitting effectiveness of steel bracing system with indirect connection applied on RC frame, but also help reaching the target of deformation capacity.

並列關鍵字

seismic retrofit ； reinforced concrete frame ； steel bracing system ； gusset plate ； mortar connection ； deformation capacity

參考文獻

林叡延，「補強用鋼框架斜撐與既有RC構架之接合研究」，碩士論文，國立台灣大學土木工程系，台北，民國102年7月，140頁。

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