• Title/Summary/Keyword: Slab bridge

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A Study on the Design of Shear Connector of Continuous Composite Bridge (연속합성형 교량의 전단연결재 설계에 관한 연구)

  • Chang, Sung Pil;Kang, Sang Gyu;Shim, Chang Su
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.351-362
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    • 1997
  • In designing short to medium-span bridges, continuous composite bridges are becoming popular due to their advantages. However, if the concrete slab in continuous composite bridge is not prestressed, negative moment occurs in the mid-support and creates problems such as cracks in the concrete slab. Therefore. it must be considered in design. Two methods of arrangement of shear connectors were conducted using finite element elastic plastic analysis. Partial interaction theory was introduced and an analytical solution based on this theory was derived. The differences in the degree of interaction were investigated using analytical solutions and finite element analyses of simple composite beam and continuous composite beams. The results of the analyses were used to determine the advantage and disadvantages as well as any precaution when necessary using partial composite during actual design and construction.

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Development of Prefabricated Voided-Slab Bridge Using PSC-I Girders (프리캐스트 I형 거더를 이용한 조립식 중공슬래브교 개발)

  • Kim, Hyun-Gi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.6
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    • pp.742-752
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    • 2017
  • The bridge type of steel concrete composite rahmen or pre-flex has been applied where a lower depth girder is required due to vertical clearance restrictions caused by the crossing of rivers and roads. On the other hand, because these types are not only complicated to manufacture and construct, but also expensive, void slab bridges may be an alternative. In this study, prefabricated PSC-I shape girder was used to make a void slab and all procedures for bridge development, such as analysis, design, fabrication, and real-scale test, were included in the scope of research. The results of this study will provide sufficient background data to be applied to the field and the structural safety has been verified through experiments.

Failure Strength Analysis of Simply Supported Sandwich Slab Bridges made by Composite Materials (복합재료로 만들어진 단순지지 샌드위치 슬래브 교량의 파괴강도해석)

  • Han, Bong-Koo;Kim, Se-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.1
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    • pp.77-84
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    • 2007
  • In this paper presented, a design method of sandwich slab bridge of simple supported made by composite materials. Many of the bridge systems, including the girders and cross-beams, and concrete decks behave as the special orthotropic plates. Such systems with sections, boundary conditions other than Navier or Levy solution types, or with irregular cross sections, analytical solution is very difficult to obtain. Thus, Finite Difference Method is used for analysis of the pertinent problem. For the design of bridge made by the composite materials, cross-section is used the form-core shape because of this shape is economical and profitable, and for output of the stress value used F.D.M. Based the experimental of a composite specialist, an equation expressing the rate of decrease of tensile strength of glass fibers based on increase of mass was obtained. From these equations, one can estimate the rate of tensile strength reduction due to increased size. Tasi-Wu failure criterion for stress space is used. Strength-failure analysis procedure, using these reduced tensile strength, is presented.

Design Automation System for Concrete Slab Bridge using Vector Graphic (벡터 그래픽을 이용한 콘크리트 슬래브교의 설계자동화)

  • Lho, Byeong Cheol;Kim, Jeong Hoon;Kim, Jong Woo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.2
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    • pp.181-192
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    • 2008
  • A Web-based design automation system for concrete slab bridge has been developed to manage the resultant documents as well as to speed up the repetitive design process. Manipulation of engineering drawings in the Web page is one of the critical functions needed for Web-based design automation. Active Server Pages (ASP) is used to that collects design parameters in the database, and eXtensible Markup Language (XML) and XML-based vector graphics are expected to facilitate the representation of engineering drawings in the Web page. In this paper, we present how we used XML and Scalable Vector Graphics (SVG) to compose engineering drawings and represent them in the Web page. XML Data Island we designed to define drawing components turned out effective in manipulating the engineering drawings in the Web page.

Effect of vehicle flexibility on the vibratory response of bridge

  • Lalthlamuana, R.;Talukdar, Sudip
    • Coupled systems mechanics
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    • v.3 no.2
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    • pp.147-170
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    • 2014
  • In the recent times, dimensions of heavy load carrying vehicle have changed significantly incorporating structural flexibility in vehicle body. The present paper outlines a procedure for the estimation of bridge response statistics considering structural bending modes of the vehicle. Bridge deck roughness has been considered to be non homogeneous random process in space. Influence of pre cambering of bridge surface and settlement of approach slab on the dynamic behavior of the bridge has been studied. A parametric study considering vehicle axle spacing, mass, speed, vehicle flexibility, deck unevenness and eccentricity of vehicle path have been conducted. Dynamic amplification factor (DAF) of the bridge response has been obtained for several of combination of bridge-vehicle parameters. The present study reveals that flexible modes of vehicle can reduce dynamic response of the bridge to the extent of 30-37% of that caused by rigid vehicle model. However, sudden change in the bridge surface profile leads to significant amount of increment in the bridge dynamic response even if flexible bending modes remain active. The eccentricity of vehicle path and flexural/torsional rigidity ratios plays a significant role in dynamic amplification of bridge response.

Experimental Study on the Cracking Loads of LB-DECKs with Varied Cross-Section Details (단면 상세가 변화된 LB-DECK의 균열하중에 대한 실험적 연구)

  • Youn, Seok-Goo;Cho, Gyu-Dae
    • Journal of the Korea Concrete Institute
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    • v.23 no.5
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    • pp.657-665
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    • 2011
  • LB-DECK, a precast concrete panel type, is a permanent concrete deck form used as a formwork for cast-in-place concrete pouring at bridge construction site. LB-DECK consists of 60 mm thick concrete slab and 125 mm height Lattice-girders partly embedded in the concrete slab. These decks have been applied to the bridges, which girder spacings are short enough to resist longitudinal cracking caused by construction loads. This paper presents experimental research work conducted to evaluate the cracking load of LB-DECKs designed for long span bridge decks. Twenty four non-composite beams and four composite beams are fabricated considering three design variables of thickness of concrete slab, height of lattice-girder, and diameter of top-bar. Static loads controlled by displacements are applied to test beams to obtain cracking and ultimate loads. Vertical displacements at the center of beams, strains of top-bar, crack propagation in concrete slab, and final failure modes are carefully monitored. The obtained cracking loads are compared to the analytical results obtained by elastic analyses. Long-term analyses using age-adjusted effective modulus method (AEMM) are also conducted to investigate the effects of concrete shrinkage on the cracking loads. Based on the test results, the tensile strength and the design details of LB-DECKs are discussed to prevent longitudinal cracking of long span bridge decks.

A Study on the Flexural Behavior of Plate Girder Bridge Decks Using a Macro-Element (매크로 요소를 사용한 판형교 바닥판의 휨거동 해석)

  • 최진유;양기재;박남회;강영종
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.1
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    • pp.13-24
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    • 2000
  • Current specification prescribes that upper and lower reinforcement mat is required in the same amount to resist negative and positive moment in bridge decks. But the negative moment is much smaller than positive moment because the actual behavior of decks consists of local deflection of slab and global deflection of girder. From this study, the analysis method based on harmonic analysis and slope-deflection method was developed and verified by finite element method. The negative moment, obtained from this method, were smaller than those computed based on the KHBDC specifications as much as 40∼50% in the middle of bridge. The amount of reduction of the design negative moment was shown herein to be dependent on variable parameters as shape factor(S/L) of slab, relative stiffness ratio of girder and deck slab, and so on. This investigations indicate that the upper reinforcement mat to resist negative moment can be removed. But further experimental study is required to consider durability and serviceability. From this new design concept, the construction expense can be reduced and the problem of decreasing durability resulting from corrosion of upper reinforcement steel settled.

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Shear lag effects on wide U-section pre-stressed concrete light rail bridges

  • Boules, Philopateer F.;Mehanny, Sameh S.F.;Bakhoum, Mourad M.
    • Structural Engineering and Mechanics
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    • v.68 no.1
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    • pp.67-80
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    • 2018
  • Recently, U-section decks have been more and more used in metro and light rail bridges as an innovative concept in bridge deck design and a successful alternative to conventional box girders because of their potential advantages. U-section may be viewed as a single vent box girder eliminating the top slab connecting the webs, with the moving vehicles travelling on the lower deck. U-section bridges thus solve many problems like limited vertical clearance underneath the bridge lowest point, besides providing built-in noise barriers. Beam theory in mechanics assumes that plane section remains plane after bending, but it was found that shearing forces produce shear deformations and the plane section does not remain plane. This phenomenon leads to distortion of the cross section. For a box or a U section, this distortion makes the central part of the slab lagging behind those parts closer to the webs and this is known as shear lag effect. A sample real-world double-track U-section metro bridge is modelled in this paper using a commercial finite element analysis program and is analysed under various loading conditions and for different geometric variations. The three-dimensional finite element analysis is used to demonstrate variations in the transverse bending moments in the deck as well as variations in the longitudinal normal stresses induced in the cross section along the U-girder's span thus capturing warping and shear lag effects which are then compared to the stresses calculated using conventional beam theory. This comparison is performed not only to locate the distortion, warping and shear lag effects typically induced in U-section bridges but also to assess the main parameters influencing them the most.

Estimation of Fatigue safety for PSC Bridge Decks (PSC 바닥판의 피로 안전성 평가)

  • 김영진;이정우;주봉철;김병석;박성용;이필구
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.525-530
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    • 2002
  • This study is peformed to propose the slab deck for the composite bridge with two girders. Considering the characteristics of the long span and the construction conditions in korea, a cast-in-place PSC deck was proposed for that bridge. To examine structural behaviors and safety of the proposed PSC deck, two real scale partitions of deck(12m××3.2m) were tested under the fatigue loading. In the test, the failure mode and behaviors of each specimen, and the ultimate load carrying capacity of the two-girder-bridge deck were identified. Generally, the failure of concrete bridge deck is caused by the local punching shear stress resulting from the moving wheel load. Even though its ultimate flexural capacity is sufficiently larger than the demand, it could be failed by the punching shear fatigue. Therefore, the fatigue safety of the proposed PSC deck should be checked.

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Temperature Analysis of PSC Box-girder Bridges Using Inverse Thermal Analysis Program (온도분포 역해석 프로그램을 이용한 PSC 박스거더 교량 단면의 온도 분포 해석)

  • Park, Min-Seok;Jo, Byung-Wan;Lee, Myung-Kue
    • Journal of the Korean Society of Safety
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    • v.21 no.4 s.76
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    • pp.95-101
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    • 2006
  • It is well known that the thermal load in PSC(prestressed concrete) box-girder bridge is the principal cause of detrimental crack. The longitudinal stress caused by the lateral stress from the temperature gradient in slab of PSC box-girder bridge has a considerable influence on the durability and economy of bridge structures. As the basic study for the rational consideration of thermal load and the derivation of design guide, the inverse thermal analysis program for PSC box-girder bridges using field measurement data is developed. In this paper, thermal analyses are performed using field monitoring data for the sample PSC box-girder bridge. It is proposed that the link between monitoring program and the inverse analysis program is available.