• Title, Summary, Keyword: composite column

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Theoretical study of UHPCC composite column behaviors under axial compression

  • Wu, Xiang-Guo;Zou, Ruofei;Zhao, Xinyu;Yu, Qun
    • Structural Engineering and Mechanics
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    • v.55 no.5
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    • pp.931-951
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    • 2015
  • To improve the durability and service life of reinforced concrete column such as bridge piers, an advanced composite column made of Ultra High Performance Cementitious Composites (UHPCC) permanent form is proposed. Based on elasticity plasticity theory, axial compression behavior of the composite column was studied theoretically. The first circumferential cracking load and ultimate limit loading capacity are derived for the composite column. Short composite column compression tests and numerical simulations using FEM method were carried out to justify the theoretical formula. The effects of UHPCC tube thickness on the axial compression behavior were studied. Using the established theoretical model and numerical simulation, the large dimension composite columns are calculated and analyzed with different UHPCC tube thickness. These studies may provide a reference for advanced composite column design and application.

Rotation capacity of composite beam connected to RHS column, experimental test results

  • Eslami, Mohammadreza;Namba, Hisashi
    • Steel and Composite Structures
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    • v.22 no.1
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    • pp.141-159
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    • 2016
  • Commonly in steel frames, steel beam and concrete slab are connected together by shear keys to work as a unit member which is called composite beam. When a composite beam is subjected to positive bending, flexural strength and stiffness of the beam can be increased due to "composite action". At the same time despite these advantages, composite action increases the strain at the beam bottom flange and it might affect beam plastic rotation capacity. This paper presents results of study on the rotation capacity of composite beam connected to Rectangular Hollow Section (RHS) column in the steel moment resisting frame buildings. Due to out-of-plane deformation of column flange, moment transfer efficiency of web connection is reduced and this results in reduction of beam plastic rotation capacity. In order to investigate the effects of width-to-thickness ratio (B/t) of RHS column on the rotation capacity of composite beam, cyclic loading tests were conducted on three full scale beam-to-column subassemblies. Detailed study on the different steel beam damages and concrete slab damages are presented. Experimental data showed the importance of this parameter of RHS column on the seismic behavior of composite beams. It is found that occurrence of severe concrete bearing crush at the face of RHS column of specimen with smaller width-to-thickness ratio resulted in considerable reduction on the rate of strain increase in the bottom flange. This behavior resulted in considerable improvement of rotation capacity of this specimen compared with composite and even bare steel beam connected to the RHS column with larger width-to-thickness ratio.

Modelling and experiment of semi rigid joint between composite beam and square CFDST column

  • Guo, Lei;Wang, Jingfeng;Zhang, Meng
    • Steel and Composite Structures
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    • v.34 no.6
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    • pp.803-818
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    • 2020
  • Semi-rigid connections with blind bolts could solve the difficulty that traditional high strength bolts were unavailable to splice a steel/composite beam to a closed section column. However, insufficient investigations have focused on the performance of semi-rigid connection to square concrete filled double-skin steel tubular (CFDST) columns. In this paper, a component model was developed to evaluate the mechanical behavior of semi-rigid composite connections to CFDST columns considering the stiffness and strength of column face in compression and column web in shear which were determined by the load transfer mechanism and superstition method. Then, experimental investigations on blind bolted composite joints to square CFDST columns were conducted to validate the accuracy of the component model. Dominant failure modes of the connections were analyzed and this type of joint behaved semi-rigid manner. More importantly, strain responses of CFDST column web and tubes verified that stiffness and strength of column face in compression and column web in shear significantly affected the connection mechanical behavior owing to the hollow part of the cross-section for CFDST column. The experimental and analytical results showed that the CFDST column to steel-concrete composite beam semi-rigid joints could be employed for the assembled structures in high intensity seismic regions.

Experimental behavior of VHSC encased composite stub column under compression and end moment

  • Huang, Zhenyu;Huang, Xinxiong;Li, Weiwen;Mei, Liu;Liew, J.Y. Richard
    • Steel and Composite Structures
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    • v.31 no.1
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    • pp.69-83
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    • 2019
  • This paper investigates the structural behavior of very high strength concrete encased steel composite columns via combined experimental and analytical study. The experimental programme examines stub composite columns under pure compression and eccentric compression. The experimental results show that the high strength encased concrete composite column exhibits brittle post peak behavior and low ductility but has acceptable compressive resistance. The high strength concrete encased composite column subjected to early spalling and initial flexural cracking due to its brittle nature that may degrade the stiffness and ultimate resistance. The analytical study compares the current code methods (ACI 318, Eurocode 4, AISC 360 and Chinese JGJ 138) in predicting the compressive resistance of the high strength concrete encased composite columns to verify the accuracy. The plastic design resistance may not be fully achieved. A database including the concrete encased composite column under concentered and eccentric compression is established to verify the predictions using the proposed elastic, elastoplastic and plastic methods. Image-oriented intelligent recognition tool-based fiber element method is programmed to predict the load resistances. It is found that the plastic method can give an accurate prediction of the load resistance for the encased composite column using normal strength concrete (20-60 MPa) while the elastoplastic method provides reasonably conservative predictions for the encased composite column using high strength concrete (60-120 MPa).

Transverse reinforcement for confinement at plastic hinge of circular composite hollow RC columns

  • Won, Deok Hee;Han, Taek Hee;Kim, Seungjun;Park, Woo-Sun;Kang, Young Jong
    • Computers and Concrete
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    • v.17 no.3
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    • pp.387-406
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    • 2016
  • Confined transverse reinforcement was arranged in a plastic hinge region to resist the lateral load that increased the lateral confinement effect in the bridge substructure. Columns increased the seismic performance through securing stiffness and ductility. The calculation method of transverse reinforcements at plastic hinges is reported in the AASHTO-LRFD specification. This specification was only proposed for solid reinforced concrete (RC) columns. Therefore, if this specification is applied for another column as composite column besides the solid RC column, the column cannot be properly evaluated. The application of this specification is particularly limited for composite hollow RC columns. The composite hollow RC column consists of transverse, longitudinal reinforcements, cover concrete, core concrete, and an inner tube inserted in the hollow face. It increases the ductility, strength, and stiffness in composite hollow RC columns. This paper proposes a modified equation for economics and rational design through investigation of displacement ductility when applying the existing specifications at the composite hollow RC column. Moreover, a parametric study was performed to evaluate the detailed behavior. Using these results, a calculation method of economic transverse reinforcements is proposed.

Environmental Friendly Connection of Composite Beams and Columns (친환경 층고 절감형 합성보의 보-기둥 접합부 상세 및 시공성 연구)

  • Hong, Won-Kee;Kim, Jin-Min;Park, Seon-Chee;Lim, Sun-Jae
    • KIEAE Journal
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    • v.7 no.6
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    • pp.113-118
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    • 2007
  • The composite beam adopted in the study was designed to reduce the floor height as well as to embed the top flange of steel frame into the slab that will enable to avoid applying the fire-resistant coating and to unify the joint method with a steel frame-type. As the steel frame and bottom concrete of the beam is pre-fabricated at the factory it could reduce the overall schedule at the jobsite. Applying such composite beam system to the work is expected to provide the efficient and enhanced performance, given the current tendency of the building construction that tends to be getting higher, larger and dense. The study focused on combining the composite beam with various column systems in a bid to propose the details thereof. A desirable composite girder can be adopted depending on site conditions through the evaluation of various beam and jointing approaches. Among the column systems applied to the study are steel column, SRC column, RC-PC column and RC column. The ways of combining with the columns addressed in the study were categorized into the rigid joint, pin joint, steel frame joint and bracket type joint. Besides, the instruction for site fabrication of beam-column was added in an effort to help set up the site fabrication procedures.

Seismic performances of centrifugally-formed hollow-core precast columns with multi-interlocking spirals

  • Hwang, Jin-Ha;Lee, Deuck Hang;Oh, Jae Yuel;Choi, Seung-Ho;Kim, Kang Su;Seo, Soo-Yeon
    • Steel and Composite Structures
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    • v.20 no.6
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    • pp.1259-1274
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    • 2016
  • A precast composite column system has been developed in this study by utilizing multi interlocking spiral steel into a centrifugally-formed hollow-core precast (CHPC) column. The proposed hybrid column system can have enhanced performances in the composite interaction behavior between the hollowed precast column and cast-in-place (CIP) core-filled concrete, the lap splice performance of bundled bars, and the confining effect of concrete. In the experimental program, reversed cyclic loading tests were conducted on a conventional reinforced concrete (RC) column fabricated monolithically, two CHPC columns filled with CIP concrete, and two steel-reinforced concrete (SRC) columns. It was confirmed that the interlocking spirals was very effective to enhance the structural performance of the CHPC column, and all the hollow-core precast column specimens tested in this study showed good seismic performances comparable to the monolithic control specimen.

Seismic Performance of a Hollow Composite Column (강합성 중공 기둥의 내진 성능)

  • Han, Taek Hee;Kim, Jung Hun;Lim, Nam Hyoung;Kang, Young Jong
    • Journal of Korean Society of Steel Construction
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    • v.20 no.2
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    • pp.215-226
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    • 2008
  • A column test was performed for a hollow composite column to evaluate its seismic performance. The seismic performances of a hollow composite column and a reinforced concrete (RC) column were evaluated and compared by quasi-static tests. Lateral displacements and lateral loads of the column specimens were measured during tests. Ductilities, absorbed energy, equivalent damping ratios, and damage indices were calculated from the recorded data. From the test results, the hollow composite column showed a seismic performance superior to the column in terms of double moment capacity, ultimate energy, and energy absorption.

Energy dissipation of steel-polymer composite beam-column connector

  • Wang, Yun-Che;Ko, Chih-Chin
    • Steel and Composite Structures
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    • v.18 no.5
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    • pp.1161-1176
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    • 2015
  • The connection between a column and a beam is of particular importance to ensure the safety of civil engineering structures, such as high-rise buildings and bridges. While the connector must bear sufficient force for load transmission, increase of its ductility, toughness and damping may greatly enhance the overall safety of the structures. In this work, a composite beam-column connector is proposed and analyzed with the finite element method, including effects of elasticity, linear viscoelasticity, plasticity, as well as geometric nonlinearity. The composite connector consists of three parts: (1) soft steel; (2) polymer; and (3) conventional steel to be connected to beam and column. It is found that even in the linear range, the energy dissipation capacity of the composite connector is largely enhanced by the polymer material. Since the soft steel exhibits low yield stress and high ductility, hence under large deformation the soft steel has the plastic deformation to give rise to unique energy dissipation. With suitable geometric design, the connector may be tuned to exhibit different strengths and energy dissipation capabilities for real-world applications.

Tests on fiber reinforced concrete filled steel tubular columns

  • Gopal, S. Ramana;Devadas Manoharan, P.
    • Steel and Composite Structures
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    • v.4 no.1
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    • pp.37-48
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    • 2004
  • This paper deals with the strength and deformation of both short and slender concrete filled steel tubular columns under the combined actions of axial compression and bending moment. Sixteen specimens were tested to investigate the effect of fiber reinforced concrete on the ultimate strength and behavior of the composite column. The primary test parameters were load eccentricity and column slenderness. Companion tests were also undertaken on eight numbers of similar empty steel tubes to highlight the synergistic effects of composite column. The test results demonstrate the influence of fiber reinforced concrete on the strength and behavior of concrete filled steel tubular columns.