층 구조를 갖는 강섬유 보강 고강도 콘크리트 보의 충격 저항 성능 향상

초록

The collapse of concrete structures by extreme loads like impact, explosion and blast from terrorist attacks causes severe property damage and casualties. Concrete has excellent impact resistance to such extreme loads in comparison with other construction materials. Nevertheless, existing concrete structures designed without consideration of the impact or blast load with high strain rate are endangered by those unexpected extreme loads. Accordingly, in this study, to improve the impact resistance, the static and impact behaviors of concrete beams including 0%∼1.5% (by volume) of 30mm long hooked steel fibers were assessed. Test results indicated that the static and impact resistances, flexural strength, ductility, etc., were steeply increased when higher steel fiber volume fractions were applied. In the case of the layered concrete (LC) beams including more steel fibers in the tensile zone, the higher static and impact resistances were obtained than those of the normal steel fiber reinforced concrete beam with an equivalent steel fiber volume fraction. The impact test results were also compared with the analyzed values by using the single degree of freedom (SDOF) system considering non-linear material behaviors of steel fiber reinforced concrete. The analysis results from SDOF system show good agreement with the experimental maximum deflections.

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