폭발하중을 받는 철근콘크리트 부재의 직접전단 파괴 및 휨 파괴 저항성능 평가를 위한 수치해석 모델 개발
Numerical Model to Evaluate Resistance against Direct Shear Failure and Bending Failure of Reinforced Concrete Members Subjected to Blast Loading
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초록
본 논문에서는 폭발하중을 받는 부재의 저항성능 평가를 위한 모멘트-곡률 관계 기반 수치해석 기법을 소개한다. 직접전단 파괴 모드를 고려하기 위하여 경험적인 직접전단응력-슬립양 관계를 기반으로 하는 무차원 스프링 요소를 도입하였다. 재료에 대해 정의된동적증가계수 식을 바탕으로 단면의 모멘트-곡률 관계에 직접적으로 적용가능한 단면의 곡률 변화율에 따른 동적증가계수 식을 제작하였다. 또한 부착슬립의 영향을 고려하기 위하여 소성힌지영역 내에 등가 휨강성을 도입하였다. 제안된 수치해석 모델의 타당성 검증을 위하여 실험결과와의 비교연구를 수행하였으며, 단자유도계 모델의 해석결과와의 비교를 통해 본 수치해석 모델의 우수성을 확인하였다. P-I 선도를 제작하여 부재의 휨 파괴 및 직접전단 파괴에 대한 저항성능을 평가하였으며, 매개변수 연구를 수행하여 P-I 선도 및 저항성능의 변화를 확인하였다.
Abstract
In this paper, we proposed a numerical model based on moment-curvature, to evaluate the resistance of reinforced concrete (RC) memberssubjected to blast loading. To consider the direct shear failure mode, we introduced a dimensionless spring element based on the empiricaldirect shear stress-slip relation. Based on the dynamic increase factor equations for materials, new dynamic increase factor equations wereconstructed in terms of the curvature rate for the section which could be directly applied to the moment-curvature relation. Additionally,equivalent bending stiffness was introduced in the plastic hinge region to consider the effect of bond-slip. To verify the validity of the proposedmodel, a comparative study was conducted against the experimental results, and the superiority of this numerical model was confirmedthrough comparison with the analytical results of the single-degree of freedom model. Pressure-impulse (P-I) diagrams were produced toevaluate the resistance of members against bending failure and direct shear failure, and additional parametric studies were conducted.
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