• Title, Summary, Keyword: quasi-static test

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Seismic fragility of a typical bridge using extrapolated experimental damage limit states

  • Liu, Yang;Paolacci, Fabrizio;Lu, Da-Gang
    • Earthquakes and Structures
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    • v.13 no.6
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    • pp.599-611
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    • 2017
  • This paper improves seismic fragility of a typical steel-concrete composite bridge with the deck-to-pier connection joint configuration at the concrete crossbeam (CCB). Based on the quasi-static test on a typical steel-concrete composite bridge model under the SEQBRI project, the damage states for both of the critical components, the CCB and the pier, are identified. The finite element model is developed, and calibrated using the experimental data to model the damage states of the CCB and the bridge pier as observed from the experiment of the test specimen. Then the component fragility curves for both of the CCB and the pier are derived and combined to develop the system fragility curves of the bridge. The uncertainty associated with the mean system fragility has been discussed and quantified. The study reveals that the CCB is more vulnerable than the pier for certain damage states and the typical steel-concrete composite bridge with CCB exhibits desirable seismic performance.

Quasi-Static Test for Seismic Performance of Circular Hollow RC Bridge Pier (원형 중공 콘크리트 교각의 내진성능에 대한 준정적 실험)

  • 정영수;한기훈;이강균;이대형
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.2
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    • pp.41-54
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    • 1999
  • Because of relatively heavy dead weight of concrete itself and unavoidable heat of massive concrete in bridge piers, circular hollow columns are widely used in Korean highway bridges. Since the occurrence of 1995 Kobe earthquake, there have been much concerns about seismic design for various infrastructures, inclusive of bridge structures. It is, however, understood that there are not much research works for nonlinear behavior of circular hollow columns subjected to eqrthquake motions. The objective of this experimental research is to investigate nonlinear behavior of circular hollow reinforced concrete bridge piers under the quasi-static cyclic load, and then to enhance their ductility by strengthening the plastic hinge region with glassfiber sheets. Particularly for this test, constant 10 cyclic loads have been repeatedly actuated to investigate the magnitude of strength degradation for the displacement ductility factor. Important test parameters are seismic design, confinement steel ratio, axial force and load pattern. It is observed from quasi-static tests for 7 bridge piers that the seismically designed columns and the retrofitted columns show better performance than the nonseismically designed colums, i.e. about 20% higher for energy dissipation capacity and about 70% higher for curvatures.

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Seismic Performance Enhancement of Reinforced Concrete Bridge Piers wrapped with Prestressed Steel Jacket by the Quasi-Static Test (프리스트레스트된 강판으로 보강된 철근콘크리트 교각의 준정적 실험에 의한 내진 성능 향상 연구)

  • Choel, Beak-Min;Chung, Young-Soo;Choi, Eun-Soo;Yang, Dong-Wook
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.77-80
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    • 2008
  • Lap splices were located in the plastic hinge region of most bridge piers that were constructed before the adoption of the seismic design provision of Korea Highway Design Specification on 1992. This research aims at evaluating the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal steels, which were strengthened with prestressed steel jacket in the plastic hinge region. Quasi-static test was used to investigate the seismic performance enhancement of RC test specimens. Conventional method applied mortar grouting inside steel jacket, but this research did not apply mortar grouting inside steel plate. Four test specimens in an aspect of 3.5 were constructed with 400 mm in diameter and 1600 mm in height. Test parameters are the lap splice of longitudinal reinforcing steels and thickness of steel jacket.

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Experimental investigation of the aeroelastic behavior of a complex prismatic element

  • Nguyen, Cung Huy;Freda, Andrea;Solari, Giovanni;Tubino, Federica
    • Wind and Structures
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    • v.20 no.5
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    • pp.683-699
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    • 2015
  • Lighting poles and antenna masts are typically high, slender and light structures. Moreover, they are often characterized by distributed eccentricities that make very complex their shape. Experience teaches that this structural type frequently suffers severe damage and even collapses due to wind actions. To understand and interpret the aerodynamic and aeroelastic behavior of lighting poles and antenna masts, this paper presents the results of static and aeroelastic wind tunnel tests carried out on a complex prismatic element representing a segment of the shaft of such structures. Static tests are aimed at determining the aerodynamic coefficients and the Strouhal number of the test element cross-section; the former are used to evaluate the critical conditions for galloping occurrence based on quasi-steady theory; the latter provides the critical conditions for vortex-induced vibrations. Aeroelastic tests are aimed at reproducing the real behavior of the test element and at verifying the validity and reliability of quasi-steady theory. The galloping hysteresis phenomenon is identified through aeroelastic experiments conducted on increasing and decreasing the mean wind velocity.

Seismic Performance Evaluation of Circular RC Bridge Piers with Longitudinal Steel Lap Splice (주철근 겹이음에 따른 철근 콘크리트 교각의 내진성능 평가)

  • 이대형;박진영;정영수;조대연;이재훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.187-193
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    • 2001
  • The object of this research is to evaluate the seismic performance of existing circular reinforced concrete bridge piers by the Quasi-static test. Existing reinforced concrete bridge piers, which were non-seismical]y designed in accordance with the conventional provisions of Korea Highway Design Specification, are needed to rating evaluate seismic performance fur probable earthquake motions in future by developing a seismic analysis computer program with estimation algorithm. This study has been performed to verify the effect of lap spliced longitudinal steel, confinement steel type and confinement steel ratio for the seismic behavior of reinforced concrete bridge piers. Quasi-static test has been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility, energy absorption, strength degradation etc.

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Quasi-Static Test for Seismic Performance of R/C Bridge Piers with Lap Splices (준정적실험에 의한 겹이음된 철근콘크리트 교각의 내진성능 평가)

  • Chung, Young-Soo;Lee, Jae-Hyung;Kim, Yong-Gon;Kim, Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.877-882
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    • 2001
  • Lap splice in plastic hinge region of RC bridge piers is inevitable because of the constructional joint between footing and column. RC circular columns with lap-splice in plastic hinge region are widely used in Korean highway bridges. It is, however, believed that there are not many experimental research works for nonlinear behavior of these columns subjected to earthquake motions. This study has been performed to verify the effect of axial force, lap splice and confinement steel ratio for the seismic behaviour of reinforced concrete bridge piers. Quasi-static test have been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility and enemy absorption.

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Seismic Retrofit of RC Columns with Lap-Spliced Longitudinal Rebars Wrapping by SMA Wires (SMA Wire를 이용한 주철근 겹침이음된 RC 교각의 내진 보강 연구)

  • Park, Yong-Kwon;Lee, Yeon-Hun;Yang, Dong-Wook;Lim, Hyeon-Sik;Chung, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.129-130
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    • 2010
  • Lap splice of longitudinal reinforcing steels was located in the plastic hinge region of most bridge piers that had been designed and constructed before the adoption of the 1992 seismic design provision of Korea Highway Design Specification. This research aims at improving the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal steels, of which the plastic hinge region was wrapped by the shape memory alloy (SMA) wires. Quasi-static test was used to investigate the seismic behaviours of RC test specimens.

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Stab Resistance of Aramid Fabric Reinforced with Waterborne Polyurethane Resin (수용성 PU 강화 아라미드 직물의 방검 특성)

  • Yoo, Joohwan;Ahn, Damiro;Kim, Ho Dong
    • Textile Science and Engineering
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    • v.50 no.4
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    • pp.252-257
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    • 2013
  • The stab resistance of aramid fabrics reinforced with waterborne polyurethane (PU) resin is investigated by quasi-static and drop-tower stab tests. The effect of PU resin treatment and tumbling on the stab resistance is also evaluated by flexural stiffness and pull-out tests. To achieve maximum stab resistance, it is essential to control the movement of fiber bundles in the fabric structure. It is also found that the tumbling process is a useful way to improve the flexibility of treated fabrics.

The Experimental Study on the Absorbed Energy of Carbon/Epoxy Composite Laminated Panel Subjected to High-velocity Impact (고속 충격을 받는 Carbon/Epoxy 복합재 적층판의 흡수 에너지 예측에 대한 실험적 고찰)

  • Cho, Hyun-Jun;Kim, In-Gul;Lee, Seokje;Woo, Kyeongsik;Kim, Jong-Heon
    • Composites Research
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    • v.26 no.3
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    • pp.175-181
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    • 2013
  • The evaluation and prediction for the absorbed energy, residual velocity, and impact damage are the key things to characterize the impact behavior of composite laminated panel subjected to high-velocity impact. In this paper, the method to predict the residual velocity and the absorbed energy of Carbon/Epoxy laminated panel subjected to high velocity impact are proposed and examined by using quasi-static perforation test and high-velocity impact test. Total absorbed energy of specimen due to the high-velocity impact can be grouped with static energy and kinetic energy. The static energy are consisted of energy due to the failure of the fiber and matrix and static elastic energy, which are related to the quasi-static perforation energy. The kinetic energy are consisted of kinetic energy of moving part of specimen, which are modelled by three modified kinetic model. The high-velocity impact test were conducted by using air gun impact facility and compared with the predicted values. The damage area of specimen were examined by C-scan image. In the high initial impact velocity above the ballistic limit, both the static energy and the kinetic energy are known to be the major contribution of the total absorbed energy.

A study on the equivalent static wind load estimation of large span roofs (대스팬 지붕구조물의 등가정적 풍하중 산정에 관한 연구)

  • Kim, Dae-Young;Kim, Ji-Young;Kim, Han-Young;Lee, Myung-Ho;Kim, Sang-Dae
    • 한국공간정보시스템학회:학술대회논문집
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    • pp.245-251
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    • 2004
  • This paper discuss the conditionally sampled actual wind pressure distributions causing peak quasi-static wind loads in the large span roofs using the wind pressures at many locations on dome models measured simultaneously in a wind tunnel. The actual extreme pressure distributions are compared itk load-response-correlation (LRC) method and the quasi-steady pressure distributions. Based on the results, the reason for the discrepancy in the LRC pressure distribution and the actual extreme pressure distribution are discussed. Futhermore, a brief discussion is made of the equivalent static wind load estimation for the large span roofs.

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