• Title, Summary, Keyword: short column

Search Result 246, Processing Time 0.035 seconds

Short - and Long-term Load Carrying Capacity of Geogrid Reinforced Stone Column - A numerical investigation (지오그리드 보강 Stone Column의 장.단기 하중 지지 특성 - 유한요소해석을 통한 고찰)

  • Lee, Dae-Young;Kim, Sun-Bin;Song, Ah-Ran;Yoo, Chung-Sik
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • /
    • pp.434-444
    • /
    • 2006
  • The stone column method is widely used in Europe as an alternative to conventional pile foundations. Several benefits of using the stone column method include sound performance, low cost, expediency of construction, and liquiefaction resistance, among others. Recently, geosynthetic-encased stone column approach has been developed to improve its' load carrying capacity through increasing confinement effect. Although such a concept has successfully applied in practice, fundamentals of the method have not been fully explored. This Paper Presents the results of an investigation on the loading carriying capacity of geogrid-encased stone column using a series of 2D finite element analyses. The results of the analyses indicated improved short- and long-term carrying capacity of the geogrid-encased stone column method over the conventional strone column method with no encasing.

  • PDF

Experimental tests on biaxially loaded concrete-encased composite columns

  • Tokgoz, Serkan;Dundar, Cengiz
    • Steel and Composite Structures
    • /
    • v.8 no.5
    • /
    • pp.423-438
    • /
    • 2008
  • This paper reports an experimental investigation of the behaviour of concrete-encased composite columns subjected to short-term axial load and biaxial bending. In the study, six square and four L-shaped cross section of both short and slender composite column specimens were constructed and tested to examine the load-deflection behaviour and to obtain load carrying capacities. The main variables in the tests were considered as eccentricity of applied axial load, concrete compressive strength, cross section, and slenderness effect. A theoretical procedure considering the nonlinear behaviour of the materials is proposed for determination of the behaviour of eccentrically loaded short and slender composite columns. Two approaches are taken into account to describe the flexural rigidity (EI) used in the analysis of slender composite columns. Observed failure mode and experimental and theoretical load-deflection behaviour of the specimens are presented in the paper. The composite column specimens and also some composite columns available in the literature have been analysed and found to be in good agreement with the test results.

Tests on fiber reinforced concrete filled steel tubular columns

  • Gopal, S. Ramana;Devadas Manoharan, P.
    • Steel and Composite Structures
    • /
    • v.4 no.1
    • /
    • pp.37-48
    • /
    • 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.

Cyclic behavior of steel beam-concrete wall connections with embedded steel columns (I): Experimental study

  • Li, Guo-Qiang;Gu, Fulin;Jiang, Jian;Sun, Feifei
    • Steel and Composite Structures
    • /
    • v.23 no.4
    • /
    • pp.399-408
    • /
    • 2017
  • This paper experimentally studies the cyclic behavior of hybrid connections between steel coupling beams and concrete shear walls with embedded steel columns. Four beam-to-wall connection specimens with short and long embedded steel columns are tested under monotonic and cyclic loads, respectively. The influence of embedment length of columns on the failure mode and performance of connections is investigated. The results show that the length of embedded steel columns has significant effect on the failure mode of connections. A connection with a long embedded column has a better stiffness, load-bearing capacity and ductility than that of a short embedded column. The former fails due to the shear yielding of column web in the joint panel, while failure of the latter is initiated by the yielding of horizontal reinforcement in the wall due to the rigid rotation of the column. It is recommended that embedded steel columns should be placed along the entire height of shear walls to facilitate construction and enhance the ductility.

Numerical analysis of the seismic performance of RHC-PVCT short columns

  • Xue, Jianyang;Zhao, Xiangbi;Ke, Xiaojun;Zhang, Fengliang;Ma, Linlin
    • Advances in concrete construction
    • /
    • v.8 no.4
    • /
    • pp.257-267
    • /
    • 2019
  • This paper presents the results of cyclic loading tests on new high-strength concrete (HC) short columns. The seismic performance and deformation capacity of three reinforced high-strength concrete filled Polyvinyl Chloride tube (RHC-PVCT) short columns and one reinforced high-strength concrete (RHC), under pseudo-static tests (PSTs) with vertical axial force was evaluated. The main design parameters of the columns in the tests were the axial compression ratio, confinement type, concrete strength, height-diameter ratio of PVCT. The failure modes, hysteretic curves, skeleton curves of short columns were presented and analyzed. Placing PVCT in the RHC column could be remarkably improved the ultimate strength and energy dissipation of columns. However, no fiber element models have been formulated for computing the seismic responses of RHC-PVCT columns with PVT tubes filled with high-strength concrete. Nonlinear finite element method (FEM) was conducted to predict seismic behaviors. Finite element models were verified through a comparison of FEM results with experimental results. A parametric study was then performed using validated FEM models to investigate the effect of several parameters on the mechanical properties of RHC-PVCT short columns. The parameters study indicated that the concrete strength and the ratio of diameter to height affected the seismic performance of RHC-PVCT short column significantly.

Short- and Long-term Load Carrying Capacity of Geogrid-encased Stone Column - A numerical investigation (지오그리드 감쌈 쇄석기둥 공법의 장.단기 하중 지지 특성 - 유한요소해석을 통한 고찰)

  • Lee, Dae-Young;Song, Ah-Ran;Kim, Sun-Bin;Yoo, Chung-Sik
    • Journal of the Korean Geotechnical Society
    • /
    • v.23 no.8
    • /
    • pp.5-16
    • /
    • 2007
  • The stone column method is widely used in Europe as an alternative to conventional pile foundations. Several benefits of using the stone column method include sound performance, low cost, expediency of construction, and liquefaction resistance among others. Recently, geosynthetic-encased stone column approach has been developed to improve its load carrying capacity through increasing confinement effect. Although such a concept has been successfully applied in practice, fundamentals of the method have not been fully explored. This paper presents the results of an investigation on the load carrying capacity of geogrid-encased stone column using a series of 2D finite element analyses. A parametric study was then conducted for influencing factors such as effect of geogrid encasement, encasement length, geogrid strength, among others. The results of the analyses indicated improved short- and long-term load carrying capacity of the geogrid-encased stone column method has advantages over the conventional stone column method without encasing.

Experimental study on circular CFST short columns with intermittently welded stiffeners

  • Thomas, Job;Sandeep, T.N.
    • Steel and Composite Structures
    • /
    • v.29 no.5
    • /
    • pp.659-667
    • /
    • 2018
  • This paper deals with the experimental study on strength the strength and deformation characteristics of short circular Concrete Filled Steel Tube (CFST) columns. Effect of vertical stiffeners on the behavior of the column is studied under axial compressive loading. Intermittently welded vertical stiffeners are used to strengthen the tubes. Stiffeners are attached to the inner surface of tube by welding through pre drilled holes on the tube. The variable of the study is the spacing of the weld between stiffeners and circular tube. A total of 5 specimens with different weld spacing (60 mm, 75 mm, 100 mm, 150 mm and 350 mm) were prepared and tested. Short CFST columns of height 350 mm, outer tube diameter of 165 mm and thickness of 4.5 mm were used in the study. Concrete of cube compressive strength $41N/mm^2$ and steel tubes with yield strength $310N/mm^2$ are adopted. The test results indicate that the strength and deformation of the circular CFST column is found to be significantly influenced by the weld spacing. The ultimate axial load carrying capacity was found to increase by 11% when the spacing of weld is reduced from 350 mm to 60 mm. The vertical stiffeners are found to effective in enhancing the initial stiffness and ductility of CFST columns. The prediction models were developed for strength and deformation of CFST columns. The prediction is found to be in good agreement with the corresponding test data.

Seismic performance of RC columns with full resistance spot welding stirrups

  • Yu, Yunlong;Dang, Zhaohui;Yang, Yong;Chen, Yang;Li, Hui
    • Structural Engineering and Mechanics
    • /
    • v.73 no.5
    • /
    • pp.543-554
    • /
    • 2020
  • This paper aims to investigate the seismic performance of RC short columns and long columns with welding stirrups. Through the low-cyclic horizontal loading test of specimens, the seismic performance indexes such as failure modes, hysteretic curve, skeleton curve, ductility, energy dissipation capacity, stiffness degradation and strength degradation were emphatically analyzed. Furthermore, the effects of shear span ratio, stirrups ratio and axial compression ratio on the performance of specimens were studied. The results showed that the seismic performance of the RC short columns with welding stirrups were basically the same as that of the RC short columns with traditional stirrups, but the seismic performance of RC long columns with welding stirrups was better than that of RC long columns with traditional stirrups. The seismic performance of RC short columns and long columns with welding stirrups could be improved by increasing stirrup ratio and shear span ratio and reducing axial pressure ratio. Moreover, the welding stirrup have the advantages of steel saving, industrialization and standardization production, convenient construction, and reducing time, which indicated that the welding stirrups could be applied in practical engineering.

Shear behavior of short square tubed steel reinforced concrete columns with high-strength concrete

  • Li, Xiang;Zhou, Xuhong;Liu, Jiepeng;Wang, Xuanding
    • Steel and Composite Structures
    • /
    • v.32 no.3
    • /
    • pp.411-422
    • /
    • 2019
  • Six shear-critical square tubed steel reinforced concrete (TSRC) columns using the high-strength concrete ($f_{cu,150}=86.6MPa$) were tested under constant axial and lateral cyclic loads. The height-to-depth ratio of the short column specimens was specified as 2.6, and the axial load ratio and the number of shear studs on the steel shape were considered as two main parameters. The shear failure mode of short square TSRC columns was observed from the test. The steel tube with diagonal stiffener plates provided effective confinement to the concrete core, while welding shear studs on the steel section appeared not significantly enhancing the seismic behavior of short square TRSC columns. Specimens with higher axial load ratio showed higher lateral stiffness and shear strength but worse ductility. A modified ACI design method is proposed to calculate the nominal shear strength, which agrees well with the test database containing ten short square TSRC columns with shear failure mode from this study and other related literature.

Seismic shear strengthening of R/C beams and columns with expanded steel meshes

  • Morshed, Reza;Kazemi, Mohammad Taghi
    • Structural Engineering and Mechanics
    • /
    • v.21 no.3
    • /
    • pp.333-350
    • /
    • 2005
  • This paper presents results of an experimental study to evaluate a new retrofit technique for strengthening shear deficient short concrete beams and columns. In this technique a mortar jacket reinforced with expanded steel meshes is used for retrofitting. Twelve short reinforced concrete specimens, including eight retrofitted ones, were tested. Six specimens were tested under a constant compressive axial force of 15% of column axial load capacity based on original concrete gross section, $A_g$, and the concrete compressive strength, ${f_c}^{\prime}$. Main variables were the spacing of ties in original specimens and the volume fraction of expanded metal in jackets. Original specimens failed before reaching their nominal calculated flexural strength, $M_n$, and had very poor ductility. Strengthened specimens reached their nominal flexural strength and had a ductility capacity factor of up to 8 for the beams and up to 5.5 for the columns. Based on the test results, it can be concluded that expanded steel meshes can be used effectively to strengthen shear deficient concrete members.