• Title/Summary/Keyword: beam-column frame

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Estimation of Beam Plastic Rotation Demands for Special Moment-Resisting Steel Frames (강구조 특수모멘트골조의 보 소성변형요구량 평가)

  • Eom, Tae-Sung
    • Journal of Korean Society of Steel Construction
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    • v.23 no.4
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    • pp.405-415
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    • 2011
  • 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.

Performance Evaluation of Steel Moment Frame and Connection including Inclined Column (경사기둥을 포함한 철골모멘트 골조 및 접합부의 성능평가)

  • Kim, Yong-Wan;Kim, Taejin;Kim, Jongho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.3
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    • pp.173-182
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    • 2013
  • The building design projects which are being proceeded nowadays pursue a complex and various shape of structures, escaping from the traditional and regular shape of buildings. In this new trend of the architecture, there rises a demand of the research in the structural engineering for the effective realization of such complex-shaped buildings which disassembles the orthogonality of frames. As a distinguished characteristics of the buildings in a complex-shape, there frequently are inclined columns included in the structural frame. The inclined column causes extra axial force and bending moment at the beam-column connection so it is necessary to assess those effects on the structural behavior of the frame and the connection by experiment or analysis. However, with comparing to the studies on the normal beam-column connections, the inclined column connections have not been studied sufficiently. Therefore, this study evaluated the beam-column connections having an inclined column using nonlinear and finite element analysis method. In this paper, steel moment frames having inclined columns were analyzed by the nonlinear pushover analysis to check the global behavior and beam-column connection models were analyzed by the finite element analysis to check the buckling behavior and the fracture potentials.

Seismic Resistance of Concrete-filled U-shaped Steel Beam-to-RC Column Connections (콘크리트채움 U형 강재보 - 콘크리트 기둥 접합부의 내진성능)

  • Hwang, Hyeon-Jong;Park, Hong-Gun;Lee, Cheol-Ho;Park, Chang-Hee;Lee, Chang-Nam;Kim, Hyoung-Seop;Kim, Sung-Bae
    • Journal of Korean Society of Steel Construction
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    • v.23 no.1
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    • pp.83-97
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    • 2011
  • In this study, the seismic details of a concrete-encased, U-shaped steel beam-to-RC column connection were developed. Three specimens of the beam-to-column connection were tested under cyclic loading to evaluate the seismic performance of the connection. The test parameters were the beam depth and the column section shape. The depths of the composite beams were 610 and 710 mm, including the slab depth. For the RC columns, a square section and a circular section were used. Special details using diagonal re-bars and exterior diaphragm plates were used to strengthen the connections with the rectangular and circular columns, respectively. The test results showed that the specimens exhibited good strength, deformation, and energy dissipation capacities. The deformation capacity exceeded 4% interstory drift angle, which is the requirement for the Special Moment Frame.

Forced Vibration Testing of Full-scale Non-seismic Reinforced Concrete Frame Structure Retrofitted Using FRP Jacketing System (FRP자켓 시스템이 보강된 비내진 철근콘크리트 골조의 실물 크기 강제 진동 실험)

  • Shin, Jiuk
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.5
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    • pp.281-289
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    • 2018
  • Existing reinforced concrete building structures have seismic vulnerabilities due to their seismically-deficient details resulting in non-ductile behavior. The seismic vulnerabilities can be mitigated by retrofitting the buildings using a fiber-reinforced polymer column jacketing system, which can provide additional confining pressures to existing columns to improve their lateral resisting capacities. This study presents dynamic responses of a full-scale non-ductile reinforced concrete frame retrofitted using a fiber-reinforced polymer column jacketing system. A series of forced-vibration testing was performed to measure the dynamic responses (e.g. natural frequencies, story drifts and column/beam rotations). Additionally, the dynamic responses of the retrofitted frame were compared to those of the non-retrofitted frame to investigate effectiveness of the retrofit system. The experimental results demonstrate that the retrofit system installed on the first story columns contributed to reducing story drifts and column rotations. Additionally, the retrofit scheme helped mitigate damage concentration on the first story columns as compared to the non-retrofitted frame.

Evaluation of Seismic Performance in Relation to Beam-Panel Zone Strength Ratio of CFT Column to H-beam Endplate Connections (CFT 기둥-H형강보 엔드플레이트 접합부의 보-패널존 강도비에 따른 내진성능 평가)

  • Kim, Young Ju;Kim, Jae Keon;Oh, Young Suk;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.12 no.6
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    • pp.769-777
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    • 2000
  • This paper presents the results of cyclic seismic performance in relation to beam-panel zone strength ratio of CFT Column to H-beam steel moment connections. Each test specimen consisted of $H-350{\times}175{\times}7{\times}11$ beam(SS400) and ${\boxe}-250{\times}250{\times}9$, ${\boxe}-250{\times}250{\times}12$ column(SPSR400). Main parameter is a column panel zone strength relative to beam strength. Energy absorption capacity available in the specimens ranged from 5.2 to 12.7(tm). If panel zone strength relative to beam strength is too strong or weak, the energy absorption capacity tended to be inferior. About steel moment-resisting frame, the test results of this experiment seem to support the investigation that permitting panel zone yielding shall be more advantageous to enhancing total seismic performance.

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Seismic reliability of precast concrete frame with masonry infill wall

  • Mahdi Adibi;Roozbeh Talebkhah;Hamid Farrokh Ghatte
    • Earthquakes and Structures
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    • v.24 no.2
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    • pp.141-153
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    • 2023
  • The presented paper considers infill masonry walls' influence on the seismic reliability of precast concrete frames. The recent Bojnord earthquake on May 13th, 2017 in Iran (MW 5.4) illustrated that the infill masonry walls play a crucial role in the damage extent and life safety issues of inhabitants in the precast concrete buildings. The incremental dynamic analysis (IDA) approach was used to determine the fragility curves of the represented damaged precast frame. Then, by integrating site hazard and structural fragilities, the seismic reliability of the represented precast frame was evaluated in different damage limit states. Additionally, the static pushover analysis (SPA) approach was used to assess the seismic performance assessment of the precast frame. Bare and infilled frames were modeled as 2D frames employing the OpenSees software platform. The multi-strut macro-model method was employed for infill masonry simulation. Also, a relatively efficient and straightforward nonlinear model was used to simulate the nonlinear behavior of the precast beam-column joint. The outputs show that consideration of the masonry infilled wall effect in all spans of the structural frame leads to a decrease in the possibility of exceedance of specified damage limit states in the structures. In addition, variation of hazard curves for buildings with and without consideration of infilled walls leads to a decrease in the reliability of the building's frames with masonry infilled walls. Furthermore, the lack of infill walls in the first story significantly affects the precast concrete frame's seismic reliability and performance.

Difference analysis of the collapse behaviors of the single-story beam-column assembly and multi-story planar frame

  • Zheng Tan;Wei-Hui Zhong;Bao Meng;Xing-You Yao;Yu-Hui Zheng;Yao Gao;Shi-Chao Duan
    • Steel and Composite Structures
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    • v.50 no.3
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    • pp.265-280
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    • 2024
  • The collapse behavior observed in single-story beam-column assembly (SSBCA) do not accurately represent the actual overall stress characteristic of multi-story frame structure (MSFS) under column loss scenario owing to ignoring the interaction action among different stories, leading to a disconnection between the anti-collapse behaviors of "components" and "overall structures", that is, the anti-collapse performance of frame structures with two different structural scales has not yet formed a combined force. This paper conducts a numerical and theoretical study to explore the difference of the collapse behaviors of the SSBCA and MSFS, and further to reveal the internal force relationships and boundary constraints at beam ends of models SSBCA and MSFS. Based on the previous experimental tests, the corresponding refined numerical simulation models were established and verified, and comparative analysis on the resistant-collapse performance was carried out, based on the validated modeling methods with considering the actual boundary constraints, and the results illustrates that the collapse behaviors of the SSBCA and MSFS is not a simple multiple relationship. Through numerical simulation and theoretical analysis, the development laws of internal force in each story beam under different boundary constraints was clarified, and the coupling relationship between the bending moment at the most unfavorable section and axial force in the composite beam of different stories of multi story frames with weld cover-plated flange connections was obtained. In addition, considering the effect of the yield performance of adjacent columns on the anti-collapse bearing capacities of the SSBCA and MSFS during the large deformation stages, the calculation formula for the equivalent axial stiffness at the beam ends of each story were provided.

Behavior of repaired RAC beam-column joints using steel welded wire mesh jacketed with cement mortar

  • Marthong, Comingstarful
    • Advances in concrete construction
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    • v.8 no.2
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    • pp.91-100
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    • 2019
  • In this paper three damaged exterior RC beam-column joints made of recycled aggregate concrete (RAC) were repaired. The aim of the study was to restore back the lost capacity of the beam-column joint to the original state or more. A relatively cheap material locally available galvanized steel welded wire mesh (GSWWM) of grid size 25 mm was used to confine the damaged region and then jacketed with cement mortar. Repaired specimens were also subjected to similar cyclic displacement as those of unrepaired specimens. Seismic parameters such as load carrying capacity, ductility, energy dissipation, stiffness degradation etc. were analyzed. Results show that repaired specimens exhibited better seismic performance and hence the adopted repairing strategies could be considered as satisfactory. These findings would be helpful to the field engineers to adopt a suitable rapid and cost efficient repairing technique for restoring the damaged frame structural joints for post earthquake usage.

Relationship Analysis of Field Work in Beam-Column System Frame Work of the Precast Concrete Public Apartment Building (보-기둥구조 PC공동주택 골조공사 작업관계 분석)

  • Kim, Ki-Ho;Kim, Jin-Won;Kim, MIn-Jun;Lee, Dong-Gun;Sohn, Jeong-Rak;Lee, Bum-Sik
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.41-42
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    • 2022
  • This study analyzed the process related to the linkage between on-site work targeting the middle size Precast Concrete(PC) public apartment building with beam-column system and prepared on-site works flow relationship diagram in which the wet process consists of core Critical Path(CP) to prepare a network diagram of the Precedence Diagram Method(PDM). Through this study, it is expected that it will be possible to maximize the project management capability by suggesting a method to minimize risk factors and the optimized process management of the beam-column system PC public apartment building.

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Seismic analysis of frame-strap footing-nonlinear soil system to study column forces

  • Garg, Vivek;Hora, Manjeet S.
    • Structural Engineering and Mechanics
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    • v.46 no.5
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    • pp.645-672
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    • 2013
  • The differential settlements and rotations among footings cannot be avoided when the frame-footing-soil system is subjected to seismic/dynamic loading. Also, there may be a situation where column(s) of a building are located near adjoining property line causes eccentric loading on foundation system. The strap beams may be provided to control the rotation of the footings within permissible limits caused due to such eccentric loading. In the present work, the seismic interaction analysis of a three-bay three-storey, space frame-footing-strap beam-soil system is carried out to investigate the interaction behavior using finite element software (ANSYS). The RCC structure and their foundation are assumed to behave in linear manner while the supporting soil mass is treated as nonlinear elastic material. The seismic interaction analyses of space frame-isolated footing-soil and space frame-strap footing-soil systems are carried out to evaluate the forces in the columns. The results indicate that the bending moments of very high magnitude are induced at column bases resting on eccentric footing of frame-isolated footing-soil interaction system. However, use of strap beams controls these moments quite effectively. The soil-structure interaction effect causes significant redistribution of column forces compared to non-interaction analysis. The axial forces in the columns are distributed more uniformly when the interaction effects are considered in the analysis.