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Title |
Evaluation of Local Damages and Residual Performance of Blast Damaged RC Beams Strengthened with Steel Fiber and FRP Sheet
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DOI |
https://doi.org/10.4334/JKCI.2014.26.5.627 |
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Keywords |
폭발시험 ; 강섬유보강콘크리트(SFRC) ; FRP 시트 ; 국부손상 ; 잔류 휨강도 ; blast test ; steel fiber reinforced concrete (SFRC) ; FRP sheet ; local damage ; residual flexural strength |
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Abstract |
In this study, standoff detonation tests and static beam tests on 160×290×2200mm RC beams were conducted to investigate the effect of local damage on the flexural strength and ductility index. And also, blast resistance of RC beams strengthened with steel fiber and FRP sheet were evaluated by these tests. The standoff detonation tests were performed with charge weight of 1kg and standoff distance of 0.1m. After the tests, crater diameters and loss weights of specimens were measured to evaluate the local damage of specimens. Flexural strength and ductility index were measured by conducting the static beam tests on the damaged and undamaged specimens. As a test results, normal concrete specimen(NC) showed relatively large crater and spall diameters that caused weight loss of 23.5kg as a local damage. Whereas, steel fiber reinforced concrete specimen(SFRC) and FRP sheet retrofitted specimens(NC-F, NC-FS) showed higher blast resistance than NC by reducing crater size and weight loss. Flexural strength and ductility index were decreased in case of local damaged specimens by detonation. Especially, large decrease of flexural strength was shown in NC as compared with intact specimen and brittle failure was occurred due to buckling of compressive reinforcement. In case of specimens strengthened with steel fiber and FRP sheet, residual flexural strength and ductility index were increased as compared with NC. In these results, it is concluded that critical local damage can be occurred unless enough standoff distance can be assured even if the charge weight is small. and it is verified that strengthening method using steel fiber and FRP sheet can increase blast resistance.
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