• Title/Summary/Keyword: high performance steel

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Cyclic test of buckling restrained braces composed of square steel rods and steel tube

  • Park, Junhee;Lee, Junho;Kim, Jinkoo
    • Steel and Composite Structures
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    • v.13 no.5
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    • pp.423-436
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    • 2012
  • In this study total of six buckling-restrained braces (BRBs) were manufactured using a square steel rod as a load-resisting core member and a hollow steel tube as restrainer to prevent global buckling of the core. The gap between the core and the tube was filled with steel rods as filler material. The performances of the proposed BRB from uniaxial and subassemblage tests were compared with those of the specimens filled with mortar. The test results showed that the performance of the BRB with discontinuous steel rods as filler material was not satisfactory, whereas the BRBs with continuous steel rods as filler material showed good performance when the external tubes were strong enough against buckling. It was observed that the buckling strength of the external tube of the BRBs filled with steel rods needs to be at least twice as high as that of the BRBs filled with mortar to ensure high cumulative plastic deformation of the BRB.

Flexural behavior of ultra high performance concrete beams reinforced with high strength steel

  • Wang, Jun-Yan;Gu, Jin-Ben;Liu, Chao;Huang, Yu-Hao;Xiao, Ru-Cheng;Ma, Biao
    • Structural Engineering and Mechanics
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    • v.81 no.5
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    • pp.539-550
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    • 2022
  • A detailed experimental program was conducted to investigate the flexural behavior of ultra high performance concrete (UHPC) beams reinforced with high strength steel (HSS) rebars with a specified yield strength of 600 MPa via direct tensile test and monotonic four-point bending test. First, two sets of direct tensile test specimens, with the same reinforcement ratio but different yield strength of reinforcement, were fabricated and tested. Subsequently, six simply supported beams, including two plain UHPC beams and four reinforced UHPC beams, were prepared and tested under four-point bending load. The results showed that the balanced-reinforced UHPC beams reinforced with HSS rebars could improve the ultimate load-bearing capacity, deformation capacity, ductility properties, etc. more effectively owing to interaction between high strength of HSS rebar and strain-hardening characteristic of UHPC. In addition, the UHPC with steel rebars kept strain compatibility prior to the yielding of the steel rebar, further satisfied the plane-section assumption. Most importantly, the crack pattern of the UHPC beam reinforced with HSS rebars was prone to transform from single main crack failure corresponding to the normal-strength steel, to multiple main cracks failure under the condition of balanced-reinforced failure, which validated by the conclusion of direct tensile tests cooperated with acoustic emission (AE) source locating technique as well.

Rheology Property of Steel Fiber Reinforced High Performance Concrete (강섬유 보강 고성능 콘크리트의 유동 특성)

  • Kim, Young-Ik;Sung, Chan-Yong
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.205-208
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    • 2002
  • This study is performed to examine the flowability and filling ability of steel fiber reinforced high performance concrete. For the estimation of the flowability and filling ability, slump flow, box height difference and L-shape filling appearence are measured and compared. The test result shows that the slump flow is $60{\pm}5cm$ to make no difference with containing steel fiber, box height difference is increased with increasing steel fiber and L-shape filling appearence is to bad with increasing steel fiber. But, proper containg of steel fiber is considered to be applied for high performance concrete without decreasing of slump flow and filling ability.

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Evaluation on Applicability of Built-up Square Tubular Compression Members Fabricated with HSA800 High Performance Steel Considering Local Buckling (국부좌굴을 고려한 건축구조용 고성능강(HSA800) 조립각형강관 압축재의 적용성 평가)

  • Yoo, Jung Han;Kim, Joo Woo;Yang, Jae Guen;Kang, Joo Won;Lee, Dong Woo
    • Journal of Korean Society of Steel Construction
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    • v.25 no.3
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    • pp.223-231
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    • 2013
  • Recently, high-performance steels have been increasingly used for structural materials in buildings and bridges with the demand for high-rise and long-span of main structures. This paper offers a series of basic study for the design specification of structural members using high performance steel, that is material properties of HSA800 (High-performance rolled steel for building structures). Built-up square tube stub columns with variables of width-to-thickness ratios are planned as a parametric study in order to investigate the local buckling behaviors and check the current design limit of width-to-thickness ratio. In addition, the buckling behaviors of stub columns obtained finite element (FE) analysis were compared with those from experimental tests. The verified FE model was used for parametric study and checked applicability of high-strength steel on current design specification.

A Study on the Weld Performance of High Strength Steel considering the Fabrication (제작을 고려한 고강도강재의 용접성능에 관한 연구)

  • Kyung, Kab Soo;Hong, Sung Wook;Park, Yong Jin
    • Journal of Korean Society of Steel Construction
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    • v.14 no.5 s.60
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    • pp.647-656
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    • 2002
  • High-strength steel in steel bridges is the key to achieving cost-efficiency because it facilitates lightweight construction and rationalizes structure. The future of high-strength steel is bright, with its use projected to expand. As such, it is necessary to evaluate precisely various factors affecting the process of fabricating high-strength steel, i.e., welding heat, strain hardening, and weldability and performance of the welded joints. This study therefore performed the maximum hardness test and y-groove weld crack test using welding processes such as SAW, FCAW, and GMAW, in order to investigate the welding performance and characteristics of welded Joints or high-strength steel produced in Korea such as SM570, POSTEN60, and POSTEN80. In addition, a series of welding tests was carried out to estimate the tensile strength, bending characteristics, absorbed energy, and hardness in welded joints.

An Experimental Study on the Property of High Performance Concrete for Concrete Filled Tube with Addition Content of Steel Fiber (강섬유 첨가량에 따른 콘크리트 충전강관용 고성능 콘크리트 특성에 관한 실험적 연구)

  • Seo, Il;Hong, Seok-Beom;Yoo, Jo-Hyeong;Park, Hee-Gon;Kim, Woo-Jae;Lee, Jae-Sam
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.05a
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    • pp.213-214
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    • 2012
  • This paper presents basic study to develop high performance concrete for concrete filled tube with addition content of steel fiber. In this study, all mixtures was added to nylon fiber (1.5 kg/㎥) and steel fiber was mixed by 0, 20 and 40 kg/㎥ respectively. To evaluate the property of high performance concrete was used to various test methods which were slump flow, air content, U-box test, O-lot test and L-flow(to 300 mm, 500 mm). Also, compressive strength test was measured by ages.

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An Experimental Study on the Evaluation of Fire-Resist Performance of High-Strength Concrete Filled steel Tube Column at Fire (화재가열을 받은 고강도 콘크리트를 충전한 CFT 기둥의 내화성능 평가에 관한 실험적 연구)

  • Lee, Hyoung-Jun;Lee, Tae-Gyu;Kim, Young-Sun;Han, Hee-Chul;Kim, Gyu-Yong;Kim, Moo-Han
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.05a
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    • pp.193-197
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    • 2008
  • Recently, it increases in use of CFT(Concrete filled steel tube, below CFT) that is an excellent internal force and deformation capacity because material and method are required to be diversification and High-Performance according to increase the super-high structure. And it is proposed to use high-strength Concrete Filled steel Tube Column. But it is difficult quantitative evaluation about fire-resist performance of CFT because steel tube bind concrete. Also, the case of high strength CFT is feared that spalling occur inside. Therefore, this study made CFT specimen that determine the factor(which is strength of concrete) and then CFT column was exposed to heating controlled as closely as possible the ISO-834 standard fire curve. Also, it tried to analyze internal temperature through nonlinear transient heat flow analysis.

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Potentials of elastic seismic design of twisted high-rise steel diagrid frames

  • Kim, Seonwoong;Lee, Kyungkoo
    • Steel and Composite Structures
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    • v.18 no.1
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    • pp.121-134
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    • 2015
  • This paper is to investigate the potentials of the elastic seismic design of twisted high-rise steel diagrid frame buildings in the strong wind and moderate/low seismicity regions. First, the prototypes of high-rise steel diagrid frames with architectural plans that have a twist angle of 0 (regular-shaped), 1, and 2 degrees were designed to resist wind. Then, the effects of the twist angle on the estimated quantities and structural redundancies of the diagrid frames were examined. Second, the seismic performance of the wind-designed prototype buildings under a low seismicity was evaluated. The response spectrum analysis was conducted for the service level earthquake (SLE) having 43-year return period and the maximum considered earthquake (MCE) having 2475-year return period. The evaluation resulted that the twisted high-rise steel diagrid frames resisted the service level earthquake elastically and most of their diagrid members remained elastic even under the maximum considered earthquake.

Engineering Properties of Steel Fiber Reinforced High Performance Concrete

  • Kim Young Ik;Sung Chan Yong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.7
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    • pp.55-67
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    • 2004
  • In this paper, the flowability, strengths, impact resistance and sulfuric acid resistance of steel fiber reinforced high performance concrete (SFHPC) for the steel fiber content and fly ash and blast furnace slag as admixtures were presented. For evaluating flowability particularly, tests of slump flow, box-type passing ability and L-type filling ability were performed. The slump flow of SFHPC was some decreased with increase of the steel fiber content. At the box-type passing ability, the difference of box height of SFHPC is greatly increased with increasing the fiber content. The L-type filling ability of SFHPC was not excellent above $0.75\% of the steel fiber content. Also, the compressive strength of SFHPC was decreased with increase of the steel fiber content, but the flexural strength of SFHPC was much higher than that of the concrete without the steel fiber. At the impact resistance, drop number of SFHPC for reaching final fracture was increased with increase of the fiber content. Also, the drop number for reaching initial fracture of lmm was increased with increase of the fiber content. At the sulfuric acid resistance, 4-week weight change of SFHPC with the steel fiber was almost similarity that of HPC without the steel fiber and was in the range of 73.6 to 81.5.

Eccentric performance of CFST columns jacketed with steel tube and sandwiched concrete

  • Weijie Li;Yiyan Lu;Yue Huang;Shan Li
    • Steel and Composite Structures
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    • v.48 no.1
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    • pp.89-102
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    • 2023
  • This study investigates the eccentric performance of concrete-filled steel tubular (CFST) stub columns strengthened with steel tube and sandwiched concrete (STSC) jackets. It was revealed that the STSC jacketing method effectively weakened the cracking of concrete in CFST columns on the convex side and the crash on the concave side. Substantial increases in the eccentric bearing capacities were demonstrated after strengthening. A numerical study was further conducted. The decrease in diameter-to-thickness ratio and increase in strength of outer tube contributed to increase in peak load of all components, whereas the increase in sandwiched concrete strength resulted in load increase on itself and had negligible effects on other components. The parametric study showed the effect of inner concrete strength on columns' bearing capacity was magnified after strengthening, whereas that of inner tube thickness was reduced. Within the parameters investigated, high-strength concrete and high-strength steel can be applied without the concern of early abrupt failure of inner low-strength concrete or steel tube.