• Title/Summary/Keyword: Cyclic plate loading test

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Structural Capacity Evaluation of Hybrid Precast Concrete Beam-Column Connections Subjected to Cyclic Loading (반복하중을 받는 하이브리드 프리캐스트 보-기둥 접합부의 성능평가)

  • Choi, Hyun-Ki;Yoo, Chang-Hee;Choi, Yun-Cheul;Choi, Chang-Sik
    • Journal of the Korea Concrete Institute
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    • v.22 no.3
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    • pp.325-333
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    • 2010
  • In this study, new moment-resisting precast concrete beam-column joint made up of hybrid steel concrete was developed and tested. This beam-column joint is proposed for use in moderate seismic regions. It has square hollow tubular section in concrete column and connecting plate in precast U-beam. The steel elements in column and beam members were connected using bolt. Furthermore, in order to prevent the premature failure of concrete in hybrid steel-concrete connection, ECC(engineered cementitious composite) was used. An experimental study was carried out investigating the joint behavior subjected to reversed cyclic loading and constant axial compressive load. Two precast beam-column joint specimens and monolithic reinforced concrete joint specimen were tested. The variables for interior joints were cast-in-situ concrete area and transverse reinforcement within the joint. Tests were carried out under displacement controlled reverse cyclic load with a constant axial load. Joint performance is evaluated on the basis of connection strength, stiffness, energy dissipation, and displacement capacity. The test results showed that significant differences in structural behavior between the two types of connection because of different bonding characteristics between steel and concrete; steel and ECC. The proposed joint detail can induce to move the plastic hinge out of the ECC and steel plate. And proposed precast connection showed better performance than the monolithic connection by providing sufficient moment-resisting behavior suitable for applications in moderate seismic regions.

Seismic Evaluation of Exposed Column-base Plate Weak-axis Connections Using L-shaped Hooked Anchor Bolts (L형 갈고리 앵커볼트를 사용한 약축방향 노출형 주각부의 내진성능 평가)

  • Lim, Woo-Young;You, Young-Chan
    • Journal of Korean Society of Steel Construction
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    • v.29 no.4
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    • pp.269-280
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    • 2017
  • In this study, seismic performance was evaluated for the exposed column-base plate weak-axis connections of small size steel structures through cyclic loading tests. The primary test parameters are the thickness of base plate, the presence of rib plates, the number of anchor bolts and embedment length of anchor bolts. To investigate the effect of bond performance of anchor bolts on the seismic performance of column-base plate connections, L-shaped round bars and thread bars were used as the hooked anchor bolts in the test specimens. Test results showed that bond performance of anchor bolts and the thickness of base plate significantly affect the structural performance and energy dissipation capacity. In particular, it was found that even if the requirements for minimum thickness of the base plate that is satisfied, the base plate can yield before the capacity of steel column reaches the plastic moment resulting in decreasing the structural performance of the connections. However, the proposed details of the connections might be considered as the partially restrained, that is semi-rigid connections. Consequently, the L-shaped thread anchor bolts is applicable in the exposed column-base plate weak-axis connections of small-size steel structures.

Improvement and Evaluation of Seismic Performance of Flat Plate Slab-Column Joint Using High Ductile Fiber-Reinforced Mortar (고인성섬유 복합모르타르를 활용한 플랫 플레이트 슬래브-기둥 접합부의 내진성능 평가 및 개선)

  • Ha, Gee-Joo;Yi, Dong-Ryul
    • Journal of the Korea Concrete Institute
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    • v.24 no.3
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    • pp.341-349
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    • 2012
  • Recently, as structures in Korea and other countries become much taller, larger, and more specialized, concrete used for constructions of these structures is required to have high performance characteristics. Especially, seismic performance of concrete must be improved to resist cyclic loading from earthquakes. Consequently, this study was performed to focus on developing optimal mixtures of high ductile fiber reinforced mortar with high ductility and durability, which have good serviceability, stability and reliability performances. Eventually, this material is expected to improve seismic performance of concrete structures such as load carrying capacity, ductility capacity, and energy dissipation capacity when applied to critical regions of flat plate slab-column joint. Ultimately, this research is intended to develop a material for basic designs and practical constructions of reinforced concrete structures. Test results showed that the maximum load carrying capacity, the ductility capacity, and the energy dissipation capacity of the test specimens titled RCFPP series were increased by 15%~34%, by 33%~37%, and by 2.14 times, respectively, compared to those of the standard specimen titled SRCFP.

Hysteretic Behavior and Seismic Resistant Capacity of Precast Concrete Beam-to-Column Connections (프리캐스트 콘크리트 보-기둥 접합부의 이력거동 및 내진성능)

  • Choi, Hyun-Ki;Choi, Yun-Cheul;Choi, Chang-Sik
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.4
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    • pp.61-71
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    • 2010
  • Five half-scale beam-to-column connections in a precast concrete frame were tested with cyclic loading that simulated earthquake-type motions. Five half -scale interior beam-column assemblies representing a portion of a frame subjected to simulated seismic loading were tested, including one monolithic specimen and four precast specimens. Variables included the detailing used at the joint to achieve a structural continuity of the beam reinforcement, and the type of special reinforcement in the connection (whether ECC or transverse reinforcement). The specimen design followed the strong-column-weak-beam concept. The beam reinforcement was purposely designed and detailed to develop plastic hinges at the beam and to impose large inelastic shear force demands into the joint. The joint performance was evaluated on the basis of connection strength, stiffness, energy dissipation, and drift capacity. From the test results, the plastic hinges at the beam controlled the specimen failure. In general, the performance of the beam-to-column connections was satisfactory. The joint strength was 1.15 times of that expected for monolithic reinforced concrete construction. The specimen behavior was ductile due to tensile deformability by ECC and the yielding steel plate, while the strength was nearly constant up to a drift of 3.5 percent.

Fatigue Strength Evaluation of Steel-Concrete Composite Bridge Deck with Corrugated Steel Plate (절곡강판을 이용한 교량용 강-콘크리트 합성 바닥판의 피로 성능평가)

  • Ahn, Jin Hee;Sim, Jung Wook;Jeong, Youn Joo;Kim, Sang Hyo
    • Journal of Korean Society of Steel Construction
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    • v.20 no.6
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    • pp.731-740
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    • 2008
  • This paper deals with the fatigue behavior and strength of a new-type of steel-concrete composite bridge deck. The new-type composite bridge deck consists of corrugated steel plate, welded T-beams, stud-type shear connectors and reinforced concrete filler. A total of eight composite bridge deck specimens were fabricated, the fatigue tests were conducted under four-point bending test with three different stress ranges in constant amplitude. According to the test results, the fatigue crack generated at the welding part of the corrugated steel plate, progressed down to the bottom of the steel plate and encountered the crack, which came out from the opposite side at the same position. After the two cracks were connected at the bottom of the steel plate, the lower flange was cut off and the fatigue crack developed up to the T-beam. And the displacements and strains of fatigue test specimens were increasing with cyclic loading number, these were changed sharply at the fatigue failure. The fatigue results are compared with the design S-N curves specified in the Korea Highway Bridge Design Specifications and data in NCHRP 102 and NCHRP 147 report. The new-type composite bridge deck has a stress category of C, which means that new-type composite bridge deck can be designed by the current fatigue design specifications provided for steel members.

Structural Performance of the Modular System with Fully Restrained Moment Connections using Ceiling Bracket (천장 브래킷을 이용한 완전강접합 모듈러 시스템의 구조성능)

  • Lee, Seung-Jae;Kwak, Eui-Shin;Park, Jae-Seong;Kang, Chang-Hoon;Shon, Su-Deok
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.33 no.12
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    • pp.37-44
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    • 2017
  • Due to structural characteristics, construction costs and duration of a modular system would be saved by minimizing the schedule on the job site. As such, it is crucial to develop a connection that can guarantee stiffness while allowing for simple assembling. Particularly, the mid- to high-rise construction of the modular system necessitates the securing of the structural stability and seismic performance of multi-unit frames and connections, and thus, the stiffness of unit-assembled structures needs to be re-evaluated and designed. However, evaluating a frame consisting of slender members and reinforcing materials is a complicated process. Therefore, the present study aims to examine the structural characteristics of a modular unit connection based a method for reinforcing connection brackets and hinges while minimizing the loss of the cross section. Toward this end, the study modeled the beam-to-column connection of a modular system with the proposed connection, and produced a specimen which was used to perform a cycling loading test. The study compared the initial stiffness, the attributes of the hysteretic behavior, and the maximum flexural moment, and observed whether the model acquired the seismic performance, compared to the flexural strength of the steel moment frame connection that is required by the Korean Building Code. The test results showed that the proposed connection produced a similar initial stiffness value to that of the theoretical equation, and its maximum strength exceeded the theoretical strength. Furthermore, the model with a larger ceiling bracket showed higher seismic performance, which was further increased by the reinforcement of the plate.

Parametric study of energy dissipation mechanisms of hybrid masonry structures

  • Gao, Zhenjia;Nistor, Mihaela;Stanciulescu, Ilinca
    • Structural Engineering and Mechanics
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    • v.78 no.4
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    • pp.387-401
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    • 2021
  • This paper provides a methodology to analyze the seismic performance of different component designs in hybrid masonry structures (HMS). HMS, comprised of masonry panels, steel frames and plate connectors is a relatively new structural system with potential applications in high seismic areas. HMS dissipate earthquake energy through yielding in the steel components and damage in the masonry panels. Currently, there are no complete codes to assist with the design of the energy dissipation components of HMS and there have been no computational studies performed to aid in the understanding of the system energy dissipation mechanisms. This paper presents parametric studies based on calibrated computational models to extrapolate the test data to a wider range of connector strengths and more varied reinforcement patterns and reinforcement ratios of the masonry panels. The results of the numerical studies are used to provide a methodology to examine the effect of connector strength and masonry panel design on the energy dissipation in HMS systems. We use as test cases two story structures subjected to cyclic loading due to the availability of experimental data for these configurations. The methodology presented is however general and can be applied to arbitrary panel geometries, and column and story numbers.

Experimental Evaluation of New Seismic Connections between Rectangular Steel Tube Column and H-shaped Beam (각형강관 기둥-H형강 보 신형상 내진접합부의 실험적 평가)

  • Jin, Jooho;Kim, DooHwan;Kim, Hyunsook;Shin, Jinwon;Park, Kooyun;Lee, Kyungkoo
    • Journal of Korean Society of Steel Construction
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    • v.30 no.2
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    • pp.77-85
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    • 2018
  • A through diaphragm is often used to ensure their stiffness for moment-resisting connections using rectangular steel-tube column and H-shaped beam. The through-diaphragm connections, however, have some difficulties for their applicabilities to the field due to the complexity of the fabrication and construction processes. This study thus proposes a new modular system of steel structures assembled only using bolts without welding, by bringing a connection module composed of rectangular steel-tube column, H-shaped beam and oneway bolt onto the site. An experimental study to evaluate the seismic performance of the proposed connection details based on the new modular system is then conducted. The length and type of the inner reinforcement plate are considered as the primary design parameters, and the strength, stiffness, ductility and energy dissipation capability of the new connections are experimentally analyzed by comparison to those of conventional through diaphragm connections.

A Study on Beam-to-Column Connections with Plate Type Energy Absorption System (플레이트형 에너지 흡수장치를 가지는 기둥-보 접합부에 관한 연구)

  • Oh, Sang Hoon;Park, Hae Yong
    • Journal of Korean Society of Steel Construction
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    • v.25 no.1
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    • pp.103-114
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    • 2013
  • Recently, there is a growing interest on sustainable connection system that makes it possible to reuse of main structural members by concentrating most of the damage in the frame caused by strong horizontal force, such as earthquake, to damper. In this study proposed a new type of damage-controlled connection system applying these concepts and analysed the major structural performance of the proposed system through the full-scale cyclic loading test and nonlinear finite element analyses. According to the result, it derived the optimal damper/beam strength ratio that minimize the damage of main members and satisfy at least the fully plastic moment of the beam. And it was to verify the possibility of applying as seismic connection details.

Seismic performance evaluation of a steel slit damper for retrofit of structures on soft soil

  • Mahammad Seddiq Eskandari Nasab;Jinkoo Kim;Tae-Sang Ahn
    • Steel and Composite Structures
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    • v.51 no.1
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    • pp.93-101
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    • 2024
  • This paper presents an experimental and analytical study on a steel slit damper designed as an energy dissipative device for earthquake protection of structures considering soil-structure interaction. The steel slit damper is made of a steel plate with a number of slits cut out of it. The slit damper has an advantage as a seismic energy dissipation device in that the stiffness and the yield force of the damper can be easily controlled by changing the number and size of the vertical strips. Cyclic loading tests of the slit damper are carried out to verify its energy dissipation capability, and an analytical model is developed validated based on the test results. The seismic performance of a case study building is then assessed using nonlinear dynamic analysis with and without soil-structure interaction. The soil-structure system turns out to show larger seismic responses and thus seismic retrofit is required to satisfy a predefined performance limit state. The developed slit dampers are employed as a seismic energy dissipation device for retrofitting the case study structure taking into account the soil-structure interaction. The seismic performance evaluation of the model structure shows that the device works stably and dissipates significant amount of seismic energy during earthquake excitations, and is effective in lowering the seismic response of structures standing on soft soil.