• Title, Summary, Keyword: 휨재

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Study on Relationship of Flexural Moment-Curvature Based on Bond Property of Reinforced Concrete Member (철근콘크리트 부재의 부착특성을 고려한 휨모멘트-곡률 관계에 관한연구)

  • 장일영
    • Magazine of the Korea Concrete Institute
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    • v.3 no.4
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    • pp.97-106
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    • 1991
  • The object of this study is to propose the Flexural moment-curvature relationship based on the bond property between concrete and steel for noncracking zone, to evaluate the flexural displacement of reinforced concrete member. The bond-slip relationship and the strain hardening effect of steel were taken into consideration in order to evaluate the spacing of the cracks and the curvature distribution. Calculated curvature distribution along the longitudinal axis was transformed into equivalent curvature distribution. The flexural displacement was calculated by means of double integrals of the equivalent curvature. Furthermore, 34 beams were tested in order to verify the proposed procedure Calculated values agreed well with the experimental data, and so it is pointed out that proposed method is widely acceptable for the practical evaluation of flexural displacement of reinforced concrete member.

A Study on Microscopic Fractrue Behavior of Mortar Using Acoustic Emission (음향방출을 이용한 mortar 재료의 미시적 파괴거동에 관한 연구)

  • 이준현;이진경;장일영;윤동진
    • Magazine of the Korea Concrete Institute
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    • v.10 no.6
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    • pp.203-211
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    • 1998
  • It is well recognized recently that acoustic emission, which is an elastic wave generated from rapid release of elastic energy in steressed solids, is very useful tool for on-line monitoring of microscopic behavior of deformation of material. In this study, three point bend test was performed to evaluate the microscopic damage progress during the loading and failure mechanism of mortar beam by monitoring the characteristic of AE signal. The relationship between AE characteristic and microscopic failure mechanism is discussed. In addition 2 dimensional AE source location based on triangular method was also done to monitor the intiation and propagation of micro crack around notch tip of mortar beam. It was shown that AE source location was very effective to predict the growth behavior of micro crack in mortar beam specimen.

An Experimental Study on the Strengh and Ductility of High-Strength Flexural Members (고강도 휨재의 강도와 연성에 관한 실험적 연구)

  • Lee, Seung-Joon
    • Journal of Korean Society of Steel Construction
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    • v.13 no.1
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    • pp.19-28
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    • 2001
  • The strength and ductility of steel flexural members are investigated experimentally in this study. As for the performance evaluation of flexural members. experimental studies on the 9 test specimens were carried out. Four specimens were fabricated from SM490 and five specimens were fabricated from SM570. The experimental results of the specimens were analyzed with focus on the flexural strength and ductility. The experimental results exhibited that all the specimens provided sufficient flexural strengthes which exceeded the nominal flexural strengthes specified in the current Limit State Design Specification by average ratio of 1.22. However. the experimental results showed that the compact-section specimens fabricated from SM570 did not provide the required rotational ductility. The yield-to-tensile strength ratio(YR) of SM570 of about 0.9 might be the causes of such insufficient capacities.

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Calculation of Limit Temperature on H-Beam Flexural Member Through the Thermal Stress Analysis under the Lateral Load (재하된 H형강 휨재의 열응력해석을 이용한 한계온도 산정)

  • Yoon, Sung Kee;Lee, Chy Hyoung;Koo, Bon Hoon
    • Journal of Korean Society of Steel Construction
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    • v.27 no.4
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    • pp.387-397
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    • 2015
  • The domestic fire resistance performance test is conducted as a prescriptive design method such as quality test. In quality test there are 2 methods, unloaded fire resistance test and fire resistance test under load. In realistic, these tests, however, have problems with expense, time and diversity of structure. This study reviewed fire resistance performance of H-beam flexural member by thermal stress analysis using finite element ABAQUS program. This research is for the performance-based design reviewing applicability of domestic standard. As a result of this study, limit temperatures per each load ratio provied for proper performance of fire resistancy.

An Experimental Study on the Precast Segmented PSC Girder with I-Shape and Box-Shape Cross-Section (I형 단면과 BOX형 단면을 갖는 프리캐스트 분절 PSC 거더의 실험적 연구)

  • Kim, Sun-Hee;Lee, Seng-Hoo;Park, Joon-Seok;Cheon, Jinuk;Yoon, Soon-Jong
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.2
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    • pp.8-16
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    • 2015
  • Prestressed concrete (PSC) is a method in which prestressed tendon is placed inside and/or outside the reinforced concrete member and the compressive force applied to the concrete in advance to enhance the engineering properties of concrete member which is weak under tension. In this paper we suggested the precast PSC girder assembled with segments of portable size and weight at the factory. The segments of precast PSC girder will be delivered and assembled as a unit of PSC girder at the site. Consequently, we suggested new-type of precast segmented PSC girder with different shapes of segment cross-section (i.e., I-shape, Box-shape). To mitigate the problems associated with the field splice between the segments of precast PSC girder anchor system is attached near the neutral axis of the girder and relatively uniform compression throughout the girder cross-section is applied. Prior to the experimental investigation, analytical investigation on the structural behavior of precast PSC girder was performed and the serviceability (deflection) and safety (strength) of the girder were confirmed. In addition, 4-point bending test on the girder was conducted to investigate the structural performance under bending. From the experimental investigation, it was found that the precast PSC girder spliced with 3 and 5 segments has sufficient in serviceability and safety conditions and it was also observed that the point where the segments spliced has no defects and the girder behaves as a unit.

Application of Direct Inelastic Design for Steel Structures (철골조를 위한 직접비탄성설계법의 적용)

  • Eom, Tae Sung;Park, Hong Gun
    • Journal of Korean Society of Steel Construction
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    • v.17 no.1
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    • pp.103-113
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    • 2005
  • In the present study, the Direct Inelastic Design (DID) for steel structures developed in the previous study was improved to expand it applicability. The proposed design method can perform inelastic designs that address the design characteristics of steel structures: Group member design, discrete member sizes, variation of moment-carrying capacity according to axial force, connection types, and multiple design criteria and load conditions. The design procedure for the proposed method was established, and a computer program incorporating the design procedure was developed. The design results from the conventional elastic method and the DID were compared and verified by the existing computer program for nonlinear analysis. Compared with the conventional elastic design, the DID addressing the inelastic behavior reduced the total weight of steel members and enhanced the deformability of the structure. The proposed design method is convenient because it can directly perform inelastic design by using linear analysis for secant stiffness. Also, it can achieve structural safety and economical design by controlling deformations of the plastic hinges.

Evaluation of Flexural Strength for UHPC Deck Joints with Lap-Spliced Reinforced Steel Bar (UHPC 바닥판 철근겹침이음 연결부의 휨강도 평가)

  • Hwang, Hoon Hee;Yeo, In Soo;Cho, Keun Hee;Park, Sung Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.92-99
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    • 2011
  • Ultra High Performance Concrete(UHPC) is a superior structural material with high strength and durability. Construction of light and slim structures is realized to apply this expectable new materials in practice. This research is a part of the project to develop UHPC precast deck system for hybrid cable stayed bridge. The main object of this study is to investigate behavior of the lap-spliced reinforced connection in UHPC. The major parameter considered in experimental plan was lap-spliced length. The 4-points bending test for 12 specimens were conducted to verify the effect of considered parameters. Test results show that the minimum value of lap spliced length of 300mm which specified in current korea high bridge design code was very conservative for UHPC precast deck system.

A Study on the Flexural Behavior of Concrete Filled Steel Tube Girder in Parametrically Varied Filling and Composition (충전 및 합성조건 변화에 따른 콘크리트 충전강관 거더의 휨거동에 관한 연구)

  • Chin, Won Jong;Kang, Jae Yoon;Choi, Eun Suk;Lee, Jung Woo
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.2A
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    • pp.109-118
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    • 2009
  • A new bridge system described in this paper uses concrete-filled steel tube (CFT) girders as a replacement for conventional girders. Experimental investigations were carried out to comprehend the flexural behavior of CFT girder. Specimens were manufactured considering several parameters such as the strength of filling material, the eventual presence and number of inner shear connectors to evaluate the bending bearing capacity of CFT girder. The experimental investigation consisted of designing and constructing a test specimen and loading it to collapse in bending to check the applicability of the system. Test results showed that concrete filled steel tube girders have good ductility and maintain their strength up to the end of the loading. The stiffening effect of the ㄱ-shaped perfobond rib is determined to contribute relatively to the increase of the bending bearing capacity.

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The Buckling Analysis of Stiffened Opening Plastes with Two Opposite Elastic Supports and Two Other Opposite Simply Supports Subjected to In-Plane Pure Bending (면내휨을 받는 2변단순지지 2변 탄성지지 유공 보강판의 좌굴해석)

  • 김일중;정동조;이용수
    • Computational Structural Engineering
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    • v.8 no.4
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    • pp.149-158
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    • 1995
  • When hot-rolled wide flanges are used as vertical compressive or bending member, opening web are often to take a space for equipments of pipe or duct. The Web of hot-rolled wide flange steel with opening may be analyzed as a rectangular plate, subjected to in plane force, and the buckling load is governed by the ultimate force of web. The result of the theory showed close agreement with the result of the finite element analysis. It was also shown that the buckling loads of stiffened opening plates could be larger than those of the plate. The stiffened opening plates for the 4-side simply supported case showed more stiffening effect than the Two Opposite Elastic Supports and Two Other Opposite Simply Supports case. In this study, we proposed the effective opening sizes that buckling loads of stiffened opening plate could be greater than those of the plates.

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Seismic Performance of High Strength Steel(HSA800) Beam-to-Column Connections with Improved Horizontal Stiffener (개량수평스티프너를 보강한 고강도강(HSA800) 접합부 내진성능평가)

  • Oh, Sang Hoon;Park, Hae Yong
    • Journal of Korean Society of Steel Construction
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    • v.26 no.4
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    • pp.361-373
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    • 2014
  • As the height and beam span of buildings built in the construction market increase, increasingly higher quality is being required of the construction materials. In response to this trend, 800MPa tensile strength class steel was developed in domestic company. Currently, experiments applying flexural member, compression member, and connections are continuously conducted, but a design guideline for high strength steel has yet to be established. Among those construction materials, for the high strength steel beam-to-column connections, the evaluation of implementing ductile connections for the high strength steel beam-to-column connections is producing pessimistic results and the number of related researches is inadequate because of the high yield ratio, which is the characteristic of high strength steel. This study on implementation of ductile connections made of high strength steel was conducted using the connection detail as the variable, for the purpose of enhancing the deformation capacity of high strength steel beam-to-column connections. Cyclic loading test and nonlinear finite element analysis were conducted with full-scale mock-up connection models with the applied connection details. As a result, the structural performance of high-strength steel beam-to-column connection with presented detail was contented with demand of Special Moment Frames of KBC standard.