• Title/Summary/Keyword: 등가단자유도해석

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Numerical Model to Evaluate Resistance against Direct Shear Failure and Bending Failure of Reinforced Concrete Members Subjected to Blast Loading (폭발하중을 받는 철근콘크리트 부재의 직접전단 파괴 및 휨 파괴 저항성능 평가를 위한 수치해석 모델 개발)

  • Ju, Seok Jun;Kwak, Hyo-Gyoung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.6
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    • pp.393-401
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    • 2021
  • In this paper, we proposed a numerical model based on moment-curvature, to evaluate the resistance of reinforced concrete (RC) members subjected to blast loading. To consider the direct shear failure mode, we introduced a dimensionless spring element based on the empirical direct shear stress-slip relation. Based on the dynamic increase factor equations for materials, new dynamic increase factor equations were constructed 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 proposed model, a comparative study was conducted against the experimental results, and the superiority of this numerical model was confirmed through comparison with the analytical results of the single-degree of freedom model. Pressure-impulse (P-I) diagrams were produced to evaluate the resistance of members against bending failure and direct shear failure, and additional parametric studies were conducted.

Arching Action Effect for Inelastic Seismic Responses of Bridge Structures (교량의 비탄성 지진응답에 대한 아칭작용의 영향)

  • Song, Jong-Keol;Nam, Wang-Hyun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.2A
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    • pp.131-143
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    • 2009
  • Under transverse earthquake shaking, arching action of bridge structures develops along the deck between the abutments thus providing the so-called deck resistance. The magnitude of the arching action for bridge structures is dependent on the number of spans, connection condition between deck and abutment or piers, and stiffness ratio between superstructure and substructure. In order to investigate the arching action effects for inelastic seismic responses of PSC Box bridges, seismic responses evaluated by pushover analysis, capacity spectrum analysis and nonlinear time-history analysis are compared for 18 example bridge structures with two types of span numbers (short bridge, SB and long bridge, LB), three types of pier height arrangement (regular, semi-regular and irregular) and three types of connection condition between superstructure and substructure (Type A, B, C). The arching action effects (reducing inelastic displacement and increasing resistance capacity) for short bridge (SB) is more significant than those for long bridge (LB). Semi-regular and irregular bridge structures have more significant arching action than regular bridges.

Effect of Seismic Design Details in Reinforced Concrete Beams on Blast-Resistance Performance (철근콘크리트 보의 내진 설계 상세가 폭발 저항 성능에 미치는 영향)

  • Kim, Kuk-Jae;Kim, Han-Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.5
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    • pp.427-434
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    • 2017
  • Recently, awareness of the public about the explosion damage has increased due to the increased risk of terrorism. The criteria for blast-resistance design is not sufficient in Korea, it is necessary to develop blast-resistance design for the stability and safety of building by static analysis of current blast-resistance design. In addition, as the increase of earthquake occurrence necessitates the seismic design, it is studied to judge the blast-resistance performance of members applying seismic design without blast-resistance design. Currently, the general analysis of blast load is to refer to UFC 3-340-02 manual. Blast-resistance performance was studied by applying characteristics of blast load through UFC 3-340-02 manual, beam converted into equivalent SDOF System. It is proved that blast-resistance performance is improved when seismic detail is applied considering the maximum deflection of normal, intermediate, and special moment frames.