• Title/Summary/Keyword: concrete composite section

Search Result 477, Processing Time 0.022 seconds

Structural behavior of slender circular steel-concrete composite columns under various means of load application

  • Johansson, Mathias;Gylltoft, Kent
    • Steel and Composite Structures
    • /
    • v.1 no.4
    • /
    • pp.393-410
    • /
    • 2001
  • In an experimental and analytical study on the structural behavior of slender circular steel-concrete composite columns, eleven specimens were tested to investigate the effects of three ways to apply a load to a column. The load was applied eccentrically to the concrete section, to the steel section or to the entire section. Three-dimensional nonlinear finite element models were established and verified with the experimental results. The analytical models were also used to study how the behavior of the column was influenced by the bond strength between the steel tube and the concrete core and the by confinement of the concrete core offered by the steel tube. The results obtained from the tests and the finite element analyses showed that the behavior of the column was greatly influenced by the method used to apply a load to the column section. When relying on just the natural bond, full composite action was achieved only when the load was applied to the entire section of the column. Furthermore, because of the slenderness effects the columns did not exhibit the beneficial effects of composite behavior in terms of increased concrete strength due to the confinement.

Simulations of PEC columns with equivalent steel section under gravity loading

  • Begum, Mahbuba;Ghosh, Debaroti
    • Steel and Composite Structures
    • /
    • v.16 no.3
    • /
    • pp.305-323
    • /
    • 2014
  • This paper presents numerical simulations of partially encased composite columns (PEC) with equivalent steel sections. The composite section of PEC column consists of thin walled welded H- shaped steel section with transverse links provided at regular intervals between the flanges. Concrete is poured in the space between the flanges and the web plate. Most of the structural analysis and design software do not handle such composite members due to highly nonlinear material behavior of concrete as well as due to the complex interfacial behaviour of steel and concrete. In this paper an attempt has been made to replace the steel concrete composite section by an equivalent steel section which can be easily incorporated in the design and analysis software. The methodology used for the formulation of the equivalent steel section is described briefly in the paper. Finite element analysis is conducted using the equivalent steel section of partially encased composite columns tested under concentric gravity loading. The reference test columns are obtained from the literature, encompassing a variety of geometric and material properties. The finite element simulations of the composite columns with equivalent steel sections are found to predict the experimental behaviour of partially encased composite columns with very good accuracy.

Design of Additional Tendon Force and Evaluation of Resistant Moment for Prestressed Concrete Composite Section (프리스트레스트 콘크리트 합성단면에 도입되는 추가 긴장력 설계와 저항모멘트 평가)

  • Yon Jung-Heum;Kim Do-Goon
    • Journal of the Korea Concrete Institute
    • /
    • v.16 no.3 s.81
    • /
    • pp.335-344
    • /
    • 2004
  • A general composite section of precast and cast-in-place concrete with prestressed and nonprestressed reinforcements was analyzed to calculate residual stresses and loss of prestressing force caused by internal constraints of concrete long-term deformation. From the analytical results, equations to design additional prestressing force and to evaluate resistant moment of the composite section were proposed. The equations shows that the additional prestressing force can be over-estimated if the loss rate of the first prestressing force is over-estimated from the lumped sum of a design code. The analytical procedure with the proposed equations has been applied to a composite section using the AASHTO Type 5 girder. The loss rates of the additional prestressing force appling to the precast concrete girder was less than those appling to the composite girder. However, the resistant moment of the additional prestressing force on the composite girder was much larger than that on the precast concrete girder. The additional prestressing force appling to the composite section was very effective for strengthening of the prestressed concrete composite girder.

A Study on the Section Design of FRP-Concrete Composite Slabs Considering Failure Behaviors (파괴 거동을 고려한 FRP-콘크리트 합성 바닥판의 단면 설계에 관한 연구)

  • 조근희;김병석;이영호
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2002.10a
    • /
    • pp.641-646
    • /
    • 2002
  • FRP-concrete composite slab is consisted of brittle materials and then shows brittle failure mechanism. This study suggests a new design approach that FRP-concrete composite slab leads to ductile failure, and investigates their failure behaviors for two types of section by numerical analysis. Box-type section is higher than I-type section in load capacity to required FRP quantity. Each section was designed so that the strain of FRP plate is 50% to its ultimate strain on initiation of concrete crushing, and it is verified that displacement ductility is more than two. Ductility capacity can be improved by reducing the strain of FRP on initiation of concrete crushing, but as the strain of FRP is reduced load capacity to required FRP quantity is also reduced. Therefore section optimization study is needed considering safety and economical efficiency.

  • PDF

Experiments on the Composite Action of Steel Encased Composite Column (강재매입형 합성기둥의 합성작용에 관한 실험)

  • Jung In Keun;Min Jin;Shim Chang Su;Chung Young Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2004.11a
    • /
    • pp.485-488
    • /
    • 2004
  • Steel encased composite columns have been used for buildings and piers of bridges. Since column section for pier is relatively larger than that of building columns, economical steel ratio need to be investigated for the required performance. Composite action between concrete and embedded steel sections can be obtained by bonding and friction. However, the behavior. of the column depends on the load introduction mechanism. Compression can be applied to concrete section, steel section and composite section. In this paper, experiments on shear strength of the steel encased composite column were performed to study the effect of confinement by transverse reinforcements, mechanical interlock by holes, and shear connectors. Shear strength obtained from the tests showed considerably higher than the design value. Confinement, mechanical interlock and stud connectors increased the shear strength and these values can be used effectively to obtain composite action of SRC columns.

  • PDF

Shear strength and shear behaviour of H-beam and cruciform-shaped steel sections for concrete-encased composite columns

  • Keng-Ta Lin;Cheng-Cheng Chen
    • Steel and Composite Structures
    • /
    • v.47 no.3
    • /
    • pp.423-436
    • /
    • 2023
  • In this research, we tested 10 simply supported concrete-encased composite columns under monotonic eccentric loads and investigated their shear behaviour. The specimens tested were two reinforced concrete specimens, three steel-reinforced concrete (SRC) specimens with an H-shaped steel section (also called a beam section), and five SRC specimens with a cruciform-shaped steel section (also called a column section). The experimental variables included the transverse steel shape's depth and the longitudinal steel flange's width. Experimental observations indicated the following. (1) The ultimate load-carrying capacity was controlled by web compression failure, defined as a situation where the concrete within the diagonal strut's upper end was crushed. (2) The composite effect was strong before the crushing of the concrete outside the steel shape. (3) We adjusted the softened strut-and-tie SRC (SST-SRC) model to yield more accurate strength predictions than those obtained using the strength superposition method. (4) The MSST-SRC model can more reasonably predict shear strength at an initial concrete softening load point. The rationality of the MSST-SRC model was inferred by experimentally observing shear behaviour, including concrete crushing and the point of sharp variation in the shear strain.

Seismic experiment and analysis of rectangular bottom strengthened steel-concrete composite columns

  • Hui, Cun;Zhu, Yanzhi;Cao, Wanlin;Wang, Yuanqing
    • Steel and Composite Structures
    • /
    • v.20 no.3
    • /
    • pp.599-621
    • /
    • 2016
  • In order to study the working mechanism of rectangular steel-concrete composite columns subjected to compression-bending load and further determine the seismic performance index, a bottom strengthened rectangular steel reinforced concrete (SRC) column with concealed steel plates and a bottom strengthened rectangular concrete filled steel tube (CFST) columns were proposed. Six column models with different configurations were tested under horizontal low cyclic loading. Based on the experiments, the load-bearing capacity, stiffness and degradation process, ductility, hysteretic energy dissipation capacity, and failure characteristics of the models were analyzed. The load-bearing capacity calculation formulas for a normal section and an oblique section of bottom strengthened rectangular steel-concrete composite columns were pesented and a finite element (FE) numerical simulation of the classical specimens was performed. The study shows that the load-bearing capacity, ductility, and seismic energy dissipation capacity of the bottom strengthened rectangular steel-concrete composite columns are significantly improved compared to the conventional rectangular steel-concrete composite columns and the results obtained from the calculation and the FE numerical simulation are in good agreement with those from the experiments. The rectangular steel-concrete composite column with bottom strengthened shows better seismic behavior and higher energy dissipation capacity under suitable constructional requirements and it can be applied to the structure design of high-rise buildings.

Flexural Behavior of PSC Beam Using High Strength Concrete (고강도 PSC BEAM 교량의 휨거동)

  • 정원기;이형준;이규정;윤석구;한승환;김기수
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1998.10b
    • /
    • pp.706-711
    • /
    • 1998
  • Structural tests of the PSC Beam bridge using high strength concrete, concrete compressive strength 700kg/$\textrm{cm}^2$, are conducted for the application including durability and serviceability of the bridge. Current design safety factors with respect to the jacking force and the service design load DB-24 are applied to the design of the bridge. Concrete compressive strength 700kg/$\textrm{cm}^2$, girder depth 2.3m, girder space 3.2m, span length 20m, and slab thickness 27cm are selected for the bridge test. The Bulb-Tee section of the girders is applied instead of I section because it is well known more stable to the longer span(40m). Static load test(4 beams) with composite and non-composite section, and fatigue load test(1 beams) with composite section are conducted. Crack moment, ultimate load, deflections with load steps, and strains of the beam section for those bridges are investigated. The structural test results of the bridges showed a good performance for a safety and a serviceability.

  • PDF

Eccentric compressive behavior of novel composite walls with T-section

  • Qin, Ying;Chen, Xin;Xi, Wang;Zhu, Xingyu;Chen, Yuanze
    • Steel and Composite Structures
    • /
    • v.35 no.4
    • /
    • pp.495-508
    • /
    • 2020
  • Double skin composite walls are alternatives to concrete walls to resist gravity load in structures. The composite action between steel faceplates and concrete core largely depends on the internal mechanical connectors. This paper investigates the structural behavior of novel composite wall system with T section and under combined compressive force and bending moment. The truss connectors are used to bond the steel faceplates to concrete core. Four short specimens were designed and tested under eccentric compression. The influences of the thickness of steel faceplates, the truss spacing, and the thickness of web wall were discussed based on the test results. The N-M interaction curves by AISC 360, Eurocode 4, and CECS 159 were compared with the test data. It was found that AISC 360 provided the most reasonable predictions.

A Study on Optimum Section of New Type Steel-Concrete Composite Beam (신형상 층고절감형 합성보의 최적단면 도출에 관한 연구)

  • Yoon, Myung-Ho;Lee, Yoon-Hee
    • Journal of the Korean Society for Advanced Composite Structures
    • /
    • v.2 no.3
    • /
    • pp.30-35
    • /
    • 2011
  • This study investigates the optimum section properties of newly developed steel-concrete composite beam. For that purpose we developed computer program calculating section properties. The suggested new beam section highly contribute to save inter-story height and reduce construction duration and cost compared with conventional steel works such as H-beam and column + RC slab system. But the section shape have different section modulus with upper and lower fiber because of the unsymmetric cross section. Therefore the parametric study on thickness-ratio of top and bottom flange plate is needed. In this paper the change of neutral axis and section modulus for thickness-ratio of up and down flage plate is analysed and discussed.