• Title/Summary/Keyword: 수정 NDRC식

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Prediction of Scabbing Limit Thickness Considering Fiber Reinforced Effect about High-Velocity Impact (고속비상체 충돌에 대한 섬유보강효과를 고려한 배면박리한계두께 예측)

  • Kim, Jung-Hyun;Kim, Gyu-Yong;Kim, Hong-Seop;Yoon, Min-Ho;Han, Sang-Hyu;Kim, Rae-Hwan
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.30-31
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    • 2014
  • Since consists of regression equation by penetration depth prediction calculated by existing NDRC formula mainly considers properties of projectile, impact velocity, compressive strength as parameter, it is difficult to apply it to fire reinforced concrete. In this study, scabbing limit thickness was predict considering fiber reinforcement effect by local fracture of concrete was evaluated through high-velocity impact test. As a result of applying fracture reduction coefficient to NDRC, it was possible to predict scabbing limit thickness of fiber reinforced concrete similarly with actual measurement.

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A Study on the Penetration Resistance and Spalling Properties of High Strength Concrete by Impact of High Velocity Projectile (고속비상체의 충돌에 의한 고강도 콘크리트의 표면관입저항성 및 배면박리성상에 관한 연구)

  • Kim, Hong-Seop;Nam, Jeong-Soo;Hwang, Heon-Kyu;Jeon, Joong-Kyu;Kim, Gyu-Yong
    • Journal of the Korea Concrete Institute
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    • v.25 no.1
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    • pp.99-106
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    • 2013
  • Concrete materials subjected to impact by high velocity projectiles exhibit responses that differ from those when they are under static loading. Projectiles generate localized effects characterized by penetration of front, spalling of rear and perforation as well as more widespread crack propagation. The magnitude of damage depends on a variety of factors such as material properties of the projectile, impact velocity, the mass and geometry as well as the material properties of concrete specimen size and thickness, reinforcement materials type and method of the concrete target. In this study, penetration depth of front, spalling thickness of rear and effect of spalling suppression of concrete by fiber reinforcement was evaluated according to compressive strength of concrete. As a result, it was similar to results of the modified NDRC formula and US ACE formula that the more compressive strength is increased, the penetration depth of front is suppressed. On the other hand, the increase in compressive strength of concrete does not affect spalling of rear suppression. Spalling of rear is controlled by the increase of flexural, tensile strength and deformation capacity.