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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society of Steel Construction
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Journal DOI :
Korean Society of Steel Construction
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Volume & Issues
Volume 23, Issue 6 - Dec 2011
Volume 23, Issue 5 - Oct 2011
Volume 23, Issue 4 - Aug 2011
Volume 23, Issue 3 - Jun 2011
Volume 23, Issue 2 - Apr 2011
Volume 23, Issue 1 - Feb 2011
Selecting the target year
Estimation of Beam Plastic Rotation Demands for Special Moment-Resisting Steel Frames
Eom, Tae-Sung ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 405~415
For the safe seismic design of buildings, it is necessary to predict the plastic deformation demands of the members as well as the story drift ratio. In the present study, a simple method of estimating the beam plastic rotation was developed for special-moment-resisting steel frame structures designed with strong column-weak beam behavior. The proposed method uses elastic analysis rather than nonlinear analysis, which is difficult to use in practice. The beam plastic rotation was directly calculated based on the results of the elastic analysis, addressing the moment redistribution, the column and joint dimensions, the movement of the plastic hinge, the panel zone deformation, the gravity load, and the strain-hardening behavior. In addition, the rocking effect of the braced frame or core wall on the beam plastic rotation was addressed. For verification, the proposed method was applied to a six-story special-moment frame designed with strong column-weak beam behavior. The predicted plastic rotations of the beams were compared with those that were determined via nonlinear analysis. The beam plastic rotations that were predicted using the proposed method correlated well with those that were determined from the nonlinear pushover analysis.
Flexural Test of H-Shape Members Fabricated of High-Strength Steel with Considering Local Buckling
Lee, Cheol-Ho ; Han, Kyu-Hong ; Park, Chang-Hee ; Kim, Jin-Ho ; Lee, Seung-Eun ; Ha, Tae-Hyu ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 417~428
Depending on the plastic deformation capacity required, structural steel design under the current codes can be classified into three categories: elastic, plastic, and seismic design. Most of the current steel codes explicitly forbid the use of a steel material with a yield strength higher than 450 MPa in the plastic design because of the concerns about its low plastic deformation capacity as well as the lack of test data on local and lateral torsional buckling behavior. In this study, flexural tests on full-scale H-shape members built with SM490A (ordinary steel or benchmark material) and HSB800 (high-strength steel) were carried out. The primary objective was to investigate the appropriateness of extrapolating the local buckling criterion of the current codes, which was originally developed for normal-strength steel, to the case of high-strength steel. All the SM490A specimens performed consistently with the current code criteria and exhibited sufficient strength and ductility. The performance of the HSB800 specimens was also very satisfactory from the strength perspective; even the specimens with a noncompact and slender flange developed the plastic moment capacity. The HSB800 specimens, however, showed an inferior plastic rotation capacity due to the premature tensile fracture of the beam bottom flange beneath the vertical stiffener at the loading point. The plastic rotation capacity that was achieved was less than 3 (or the minimum level required for a plastic design). Although the test results in this study indicate that the extrapolation of the current flange local-buckling criterion to the case of high-strength steel is conservative from the elastic design perspective, further testing together with an associated analytical study is required to identify the causes of the tensile fracture and to establish a flange slenderness criterion that is more appropriate for high-strength steel.
Explicit Stress-Erection and Ultimate Load Analysis of Unit STRARCH Frame Considering Geometrically and Materially Nonlinear Characteristics
Lee, Kyoung-Soo ; Han, Sang-Eul ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 429~438
In this study, the explicit numerical algorithm was proposed to simulate the stress erection process and ultimate-load analysis of the strarch (stressed arch) system. The strarch system is a unique and innovative structural system and member prestress comprising prefabricated plane truss frames erected through a post-tensioning stress erection procedure. The flexible bottom chord, which has sleeve and gap details, is closed by the reaction force of the prestressing tendon. The prestress imposed on the tendon will enable the strarch system to be erected. This post-tensioning process is called "stress erection process." During this process, plastic rigid-body rotation occurs to the flexible top chord due to the excessive amount of plastic strain, and the structural characteristic is unstable. In this study, the dynamic relaxation method (DRM) was adopted to calculate the nonlinear equilibrium equation of the system, and a displacement-based finite-element-formulated filament beam element was used to simulate the nonlinear behavior of the top chord sections of the strarch system. The section of the filament beam element was composed by the amount of filaments, which can be modeled by various material models. The Ramberg-Osgood and bilinear kinematic elastic plastic material models were formulated for the nonlinear material behaviors of the filaments. The numerical results that were obtained in the present study were compared with the experiment results of the stress erection and with the results of the ultimate-load analysis of the strarch unit frame. The results of the present studies are in good agreement with the previous experiment results, and the explicit DRM enabled the analysis of the post-buckling behaviors of the strarch unit frame.
Nonlinear Analysis of Internally Confined Hollow CFT Columns
Han, Taek-Hee ; Won, Deok-Hee ; Kang, Young-Jong ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 439~454
A nonlinear analysis model for internally confined hollow concrete-filled tube (ICH CFT) columns was suggested and was verified by the test results obtained by the previous researchers. The suggested model considered the confining effect and nonlinearity of concrete. The verified results showed that the suggested model was reasonable and reliable for predicting the behavior of an ICH CFT column. Additionally, a simple parametric study was carried out. The strength of concrete, the hollow ratio of a column, and the thickness of an inner tube were selected as parameters affecting the behavior of an ICH CFT column. The analysis results showed that the concrete strength and the thickness of the inner tube affect the axial strength and moment capacity of the column while the hollow ratio affects only its axial strength.
Buckling Analysis of Curved Stiffened Web Plate using Eight and Nine-Node Flat Shell Element with Substitute Shear Strain Field
Ji, Hyo-Seon ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 455~464
In this study, the buckling analysis of the vertically curved stiffened web plate was conducted through finite-element analysis, using an eight- and nine-node flat shell element with a substitute shear strain field. To investigate the buckling behavior of the vertically curved web plate with a longitudinal or vertical stiffener under in-plane moment loading, parametric studies were conducted for the variation of the width (b) and ratio of the bending stiffness of the stiffener to that of the plate (
). The static behavior of the vertically curved web plate without a stiffener was also investigated, and then the buckling abilities of the longitudinal and vertical stiffeners were compared under moment loading.
Size and Shape Optimization of Truss Structures using Micro Genetic Algorithm
Kim, Dae-Hwan ; Yoon, Byoung-Wook ; Lee, Jae-Hong ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 465~474
In this study, a microgenetic algorithm was used to find the optimum cross-section and shape of dome structures. The allowable stress and Euler buckling stress were considered constraints when the weight of the trusses was minimum. The design optimization of the truss structures involved arriving at the optimum sizes of the cross-section and geometric coordinate. The features of the proposed method, which helped in the modeling of and application to the optimal design of truss structures, were demonstrated using the microgenetic algorithm, by solving sample problems.
A Simple Modification of the First-order Shear Deformation Theory for the Analysis of Composite Laminated Structures
Chun, Kyoung-Sik ; Ji, Hyo-Seon ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 475~481
In this study, a simplified method of improving not only transverse shear stress but also shear strain based on the first-order shear deformation theory was developed. Unlike many established methods, such as the higher-order shear deformation and layerwise theories, this method can easily apply to finite elements as only
continuity is necessary and the formulation of equations is very simple. The basic concept in this method, however, must be corrected:the distribution of the transverse shear stresses and shear strains through the thickness from the formulation based on the higher-order shear deformation theory. Therefore, the shear correction factors are no longer required, based on the first-order shear deformation theory. Numerical analyses were conducted to verify the validity of the proposed formulations. The solutions based on the simplified method were in very good agreement with the results considering the higher-order shear deformation theory.
Evaluation of the Applicability of Structural Steels to Cold Regions by the Charpy Impact Test
Lee, Chin-Hyung ; Shin, Hyun-Seop ; Park, Ki-Tae ; Yang, Seunng-Hyun ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 483~491
The fabrication of steel structural members always involves welding process such as flux cored arc welding. Therefore, for the application of structural steels to cold regions, it is a prerequisite to clarify the service temperature of the welded joints in order to ensure the structural integrity of the welded parts. In this study, the Charpy impact test was conducted to evaluate the service temperature of structural steel weld. The Charpy impact test is a commercial quality control test for steels and other alloys used in the construction of metallic structures. The test allows the material properties for service conditions to be determined experimentally in a simple manner with a very low cost. Standard V-notch Charpy specimens were prepared and tested under dynamic loading condition. The service temperatures of the weld metal, HAZ (heat affected zone) and base metal were derived by the absorbed energy and the impact test requirements; thus the applicability of the structural steels to cold regions was discussed in detail.
A Study on the Concrete Breakout Capacity Evaluation of Medium-to-Large size CIP Anchor Bolts under Tension Loading
Park, Yong-Myung ; Jeon, Myeong-Hui ; Lee, Kun-Jun ; Kim, Cheol-Hwan ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 493~501
cone failure theory has been used for concrete anchor bolt design, but the CCD (concrete capacity design) method was adopted as a new design method in 2000. The method was allowed to be used, however, only for anchors with a diameter of less than 50 mm and an embedment depth of less than 635 mm because it is based on the experiment results from medium-sized to small anchor bolts. Therefore, it is necessary to develop a rational concrete breakout capacity equation for medium-sized to large anchor bolts. In this study, tension tests on an M56 cast-in-place single anchor bolt with an effective embedment depth of 400-450 mm were carried out for the five test specimens. Based on the test results together with the other recent test results, the applicability of the concrete breakout capacity equation in the current design code to the large to medium-sized anchor bolts with an embedment depth of 280-1,200 mm was estimated.
Cyclic Seismic Testing of Cruciform Concrete-Filled U-Shape Steel Beam-to-H Column Composite Connections
Park, Chang-Hee ; Lee, Cheol-Ho ; Park, Hong-Gun ; Hwang, Hyeon-Jong ; Lee, Chang-Nam ; Kim, Hyoung-Seop ; Kim, Sung-Bae ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 503~514
In this research, the seismic connection details for two concrete-filled U-shape steel beam-to-H columns were proposed and cyclically tested under a full-scale cruciform configuration. The key connecting components included the U-shape steel section (450 and 550 mm deep for specimens A and B, respectively), a concrete floor slab with a ribbed deck (165 mm deep for both specimens), welded couplers and rebars for negative moment transfer, and shear studs for full composite action and strengthening plates. Considering the unique constructional nature of the proposed connection, the critical limit states, such as the weld fracture, anchorage failure of the welded coupler, local buckling, concrete crushing, and rebar buckling, were carefully addressed in the specimen design. The test results showed that the connection details and design methods proposed in this study can well control the critical limit states mentioned above. Especially, the proposed connection according to the strengthening strategy successfully pushed the plastic hinge to the tip of the strengthened zone, as intended in the design, and was very effective in protecting the more vulnerable beam-to-column welded joint. The maximum story drift capacities of 6.0 and 6.8% radians were achieved in specimens A and B, respectively, thus far exceeding the minimumlimit of 4% radians required of special moment frames. Low-cycle fatigue fracture across the beam bottom flange at a 6% drift level was the final failure mode of specimen A. Specimen B failed through the fracture of the top splice plate of the bolted splice at a very high drift ratio of 8.0% radian.
Material Properties of 400MPa Grade Hot Rolled H-beam(SHN400) for Building Structure
Kim, Hee-Dong ; Choi, Byoung-Jeong ; Kim, Sang-Sub ; Kim, Chul-Hwan ; Oh, Young-Suk ;
Journal of Korean Society of Steel Construction, volume 23, issue 4, 2011, Pages 515~522
The purpose of this study was to evaluate the material characteristics of SHN400 steel, which is suitable as a steel material for building structures, using the experimental approach. For this purpose, the chemical composition test, tensile test, macro test, micro test, and charpy notch impact test were conducted with specimens taken from the highest, thickest, and commonly used H-beams for girder or beam members. Each test was conducted under the Korean Standard(KS) test conditions. All the test results satisfied the requirements of KS (KS D 3866) and the steel material for seismic design. The carbon equivalent value (Ceq), which is related to weldability, and the yield ratio, which is related to inelastic behavior, showed especially good results. Thus, SHN400 is definitely suitable as the steel material for building structures.