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Title |
Seismic Performance Evaluation of Unreinforced and ECC-jacketed Masonry Fences using Shaking Table Test
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Authors |
이용훈(Yonghun Lee) ; 김진우(Jinwoo Kim) ; 김재환(Jae-Hwan Kim) ; 엄태성(Tae-Sung Eom) ; 이상현(Sang-Hyun Lee) |
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DOI |
https://doi.org/10.11112/jksmi.2023.27.6.182 |
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Keywords |
ECC 자켓; 조적담장; 내진보강; 진동대 실험 ECC jacket; Masonry fence; Seismic retrofit; Shaking table test |
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Abstract |
In this study, the efficacy of Engineered Cementitious Composite(ECC) jacket for masonry fences subjected to lateral dynamic load was experimentally verified through a shaking table test, comparing it with the performance of an unreinforced masonry(URM) fence. Firstly, dominant frequencies, modal damping ratios and deformed shapes were identified through an impact hammer test. URM and ECC-strengthened fences with heights of 940mm and 970mm had natural frequencies of 6.4 and 35.3Hz, and first modal damping ratios of 7.0 and 5.3%, respectively. Secondly, a shaking table test was conducted in the out-of-plane direction, applying a historical earthquake, El Centro(1940) scaled from 25 to 300%. For the URM fence, flexural cracking occurred at the interface of brick and mortar joint(i.e., bed joint) at the ground motion scaled to 50%, and out-of-plane overturning failure followed during the subsequent test conducted at the ground motion scaled to 30%. On the other hand, the ECC-jacketed fence showed a robust performance without any crack or damage until the ground motion scaled to 300%. Finally, the base shear forces exerted upon the URM and ECC-jacketed fences by the ground motions scaled to 25~300% were evaluated and compared with the ones calculated according to the design code. In contrast to the collapse risk of the URM fence at the ground motion of 1,000-year return period, the ECC-jacketed fence was estimated to remain safe up to the 4,800-year return period ground motion.
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