scholarly journals Steel Beam-Column Joint with Discontinuous Vertical Reinforcing Bars

2015 ◽  
pp. 197-204
Author(s):  
Ju-Yun Hu ◽  
Won-Kee Hong ◽  
Seon-Chee Park ◽  
Jisoon Kim
Keyword(s):  
Load Transfer ◽  
Precast Concrete ◽  
Steel Plates ◽  
Steel Beam ◽  
Test Results ◽  
Reinforcing Bars ◽  
Concrete Frames ◽  
Steel Members ◽  
Column Joint ◽  
In Parenthesis

The authors proposed steel beam-column connections for precast concrete frames in previous studies. The steel-concrete composite frames provided fast assembly time as steels with economy of concrete structures. However, when enough space is not available at column-beam joints steel sections from beams cannot be connected with column brackets. This paper suggests that some vertical reinforcing bars are disconnected at joints by connecting vertical steel reinforcements to steel plates placed above and below column steels to provide load transferring path. Loads from re-bars are transferred to steel plates, column steels and back to steel plates and re-bars below column steels. Re-bars connected to steel plates by bolts at above and below column steel are discontinued at joint to provide spaces for connections between column brackets and beam steels. Extensive experiments were performed to verify load transfer from re-bars to steel plates above joints and steel plates to re-bars below joint. The flexural load bearing capacity of a column with total of 24 vertical re-bars were compared to columns with discontinuous re-bars at joints. The number of discontinuous re-bars at joint used in column specimen was 0 (0.0%), 4 (16.7%), 12 (50.0%), and 20 (83.3%). The numbers in parenthesis are the percentages of discontinuous rebars to the total number of vertical re-bars of control column. Experiments showed how loads from vertical steel reinforcements that were cut off at joints were transferred to steel plate. The test results also demonstrated that a part of flexural capacities were reduced for specimen with discontinuous vertical re-bars. The reduction of 6.0 %, 13.7% and 54.0% of flexural capacities were observed for columns with 4 (16.7%), 12 (50.0%) and 20 (83.3%) discontinuous vertical rebars, respectively. The test results can be used to design vertical reinforcing bars and column joints that can provide space for column brackets to which steel members of beams are connected.

scholarly journals Steel beam–column joint with discontinuous vertical reinforcing bars

2017 ◽  
Vol 23 (4) ◽  
pp. 440-454 ◽  
Author(s):  
Ju-Yun HU ◽  
Won-Kee HONG
Keyword(s):  
Load Transfer ◽  
Low Cost ◽  
Precast Concrete ◽  
Steel Plates ◽  
Steel Beam ◽  
Reinforcing Bars ◽  
Concrete Frames ◽  
Transfer Path ◽  
Composite Frames ◽  
Column Joint

The authors have previously proposed steel beam–column connections for precast concrete frames. The steel–concrete composite frames combined the advantages of the fast assembly of steel and the low cost of concrete structures. However, when not enough space is available at column–beam joints, steel sections from beams cannot be connected with column brackets. To address this issue, this paper explores the strategy of disconnecting some vertical reinforcing bars at the joints by connecting vertical steel reinforcements to steel plates placed above and below column steels, to provide a load transfer path. Loads from re-bars are transferred to steel plates, column steels, and back to steel plates and re-bars below the column steels. This strategy provided space for beam–column joints of composite frames. Extensive experiments were performed to verify load transfer from re-bars to steel plates above joints and from the steel plates to re-bars below the joint. The flexural load-bearing capacity of a column with a total of 24 vertical re-bars was compared to that of columns with discontinuous re-bars at the joints; the number of discontinuous re-bars at the joint used in the column specimens tested was 0 (0.0%), 4 (16.7%), 12 (50.0%), and 20 (83.3%).

scholarly journals Structural Performance of a Precast Concrete Modular Beam Using Bolted Connecting Plates

2021 ◽  
Vol 11 (24) ◽  
pp. 12110
Author(s):  
Kyong Min Ro ◽  
Min Sook Kim ◽  
Chang Geun Cho ◽  
Young Hak Lee
Keyword(s):  
Precast Concrete ◽  
Steel Plates ◽  
Structural Performance ◽  
Modular System ◽  
Beam Specimen ◽  
Test Results ◽  
Reinforcing Bars ◽  
Bolted Connection ◽  
Modular Units ◽  
Modular Structures

In modular structures, prefabricated modular units are joined at the construction site. Modular structures must ensure splicing performance by connecting modular units sufficiently. The bolted connection using steel plates may suffer from alignment issues and corrosion problems. In a precast concrete (PC) modular system, there is difficulty grouting the sleeves when splicing reinforcing bars. This study proposed a PC modular beam using a bolted connecting plate to deal with issues in typical steel modules and PC modules. The structural performance was evaluated by flexural and shear tests on two monolithic beams and two proposed PC specimens. The test results showed that the structural performance of the PC modular specimen was 88% of that of the monolithic reinforced concrete (RC) beam specimen and 102% of the strength calculated by ACI 318-19. Therefore, the proposed PC modular system using bolted connecting plates can solve the problems observed in typical steel and PC modules and improve the structural performance.

scholarly journals A comparison of the behaviour of reinforced concrete beam-column joints designed for ductility and limited ductility

1988 ◽  
Vol 21 (4) ◽  
pp. 255-278 ◽  
Author(s):  
R. Park ◽  
Ruitong Dai
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
The Other ◽  
Vertical Shear ◽  
Test Results ◽  
Reinforcing Bars ◽  
Design Code ◽  
Concrete Frames ◽  
Column Joint

Four beam-interior column Units were designed, constructed and tested subjected to simulated earthquake and gravity loading. One Unit followed the requirements of the New Zealand concrete design code NZS 3101:1982 for structures designed for ductility. The other three Units only partly followed the requirements of NZS 3101, in order to obtain information on the behaviour of beam-column joints of limited ductility. Plastic hinging was designed to occur in the beams. The major test variables were the quantity of horizontal and vertical shear reinforcement in the beam-interior column joint cores and the diameter of the beam longitudinal reinforcing bars passing through the joint cores. The test results indicted that the current NZS 3101 detailing requirements for shear and bond in the beam-interior column joint core regions of ductile reinforced concrete frames could be relaxed.

Experimental Investigations on the Seismic Behavior of Precast Concrete Columns with Novel Box Connections

2019 ◽  
Vol 14 (02) ◽  
pp. 2050007
Author(s):  
Xizhi Zhang ◽  
Shengbo Xu ◽  
Shaohua Zhang ◽  
Gaodong Xu
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Seismic Behavior ◽  
Load Transfer ◽  
Precast Concrete ◽  
Hysteretic Behavior ◽  
Experimental Investigations ◽  
Test Results ◽  
Energy Dissipation Capacity

In this study, two types of novel box connections were developed to connect precast concrete (PC) columns and to ensure load transfer integrity. Cyclic loading tests were conducted to investigate the seismic behavior of the PC columns with proposed connections as well as the feasibility and reliability of novel box connections. The failure mode, hysteretic behavior, bearing capacity, ductility, stiffness degradation and energy dissipation were obtained and discussed. The test results indicated that the all PC columns exhibited the ductile flexural failure mode and that the proposed connections could transfer the force effectively. The adoption of novel box connections could improve the deformation capacity and energy dissipation capacity of PC columns. A higher axial compression ratio could enhance the bearing capacity of PC column with proposed connection but would significantly deteriorate the ductility and energy dissipation capacity. Finite element models were developed and the feasibility of the models was verified by the comparison with the test results.

Mechanical Performance of Large Cantilevered CFT Beam-Column Joint in Jiangyin Magic Cube Time Square

2010 ◽  
Vol 163-167 ◽  
pp. 25-31
Author(s):  
Fei Wang ◽  
Yong Feng Luo ◽  
Xiao Nong Guo ◽  
Han Xu ◽  
Ping He
Keyword(s):  
Load Transfer ◽  
Mechanical Performance ◽  
Large Diameter ◽  
Element Model ◽  
Steel Beams ◽  
Test Results ◽  
Column Joint ◽  
Scale Test ◽  
Magic Cube ◽  
The Finite Element Model

The leading building in Magic Cube Time Square in Jiangyin is a rare large-cantilevered structure in China, with the standard floors overhanging 9m outwards. Concrete filled tube columns in large diameter and steel beams are applied in the peripheral part of the building frame. In this research, the full-scale test is conducted to investigate the mechanical performance of the concrete-filled beam-column joint. Self-balanced loading frame with dimensions of 15m×10m×10m is built due to the complexity of the joint, the greatness of load and the difficulty of loading condition. Meanwhile, the finite element model is generated to inspect the performance of the beam-column joint under the test loads for verification. Through comparisons of test results and FEM results, good mechanical performance and reasonable load transfer mechanism of the joint are presented in the paper. It is verified that the joint is reliable under 1.3 times of the design load. The effect of ring stiffeners is also studied in this paper.

scholarly journals Influence of the Ribs Parallel to Web on Warping and Load-Bearing Capacity of a Steel I-Beam

2019 ◽  
Vol 29 (4) ◽  
pp. 141-148 ◽  
Author(s):  
Krzysztof Wierzbicki ◽  
Maciej Szumigała
Keyword(s):  
Bearing Capacity ◽  
Cross Sections ◽  
Steel Plates ◽  
Steel Beam ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Plane Parallel ◽  
Steel Members ◽  
Plane Bending ◽  
The Web

Abstract The article analyses the method of enhancing a steel beam by adding additional steel members like ribs. They are rigidly connected with both flanges in a plane parallel to the web. That plates reduces warping during in-plane bending of steel beam under lateral-torsional bucking. Different thicknesses of steel plates used as ribs and different cross-sections were taken into account. Calculations were conducted using FEM and ABAQUS CAE environment. The outcomes were compared with ones from previous studies which concerned an influence of endplates on load-bearing capacity of an I-beam.

scholarly journals Hysteretic Response of Tilt-Up Concrete Precast Walls with Embedded Steel Plate Connections

2020 ◽  
Vol 12 (19) ◽  
pp. 7907
Author(s):  
Hyun-Do Yun ◽  
Hye-Ran Kim ◽  
Won-Chang Choi
Keyword(s):  
Prestressed Concrete ◽  
Structural Integrity ◽  
Precast Concrete ◽  
American Concrete Institute ◽  
Steel Plates ◽  
Test Results ◽  
Wall Panel ◽  
Concrete Wall ◽  
Concrete Panels ◽  
Wall Panels

Many connection systems are available that can transfer tension and shear loads from a precast concrete wall panel to a floor slab. However, due to the insufficient anchor depth in relatively thin precast concrete panels, it is difficult to attain adequate ductility and stiffness to ensure structural integrity. Based on the authors’ previous research results, the supplementary reinforcement of embedded steel plates in precast concrete wall panels can enhance stiffness while maintaining allowable displacement and ductility. In this study, three full-size tilt-up precast concrete panels with embedded steel plates were fabricated. Lateral cyclic loads were applied to full support structures consisting of a precast concrete wall panel and a foundation. The test results were compared with the results predicted using existing code equations found in the American Concrete Institute 318-14 and the Prestressed Concrete Institute Handbooks. The test results confirm that the supplementary reinforcement of thin precast concrete wall panels can provide (i) the required strength based on current code equations, (ii) sufficient ductility, and (iii) the energy dissipation capacity to resist cyclic loading.

Low Reversed Cyclic Loading Test for New Precast Concrete Beam to Column Connection

2014 ◽  
Vol 1079-1080 ◽  
pp. 160-165
Author(s):  
Jian Bing Yu ◽  
Zheng Xing Guo ◽  
Dong Zhi Guan
Keyword(s):  
Cyclic Loading ◽  
Precast Concrete ◽  
Plastic Hinge ◽  
Control Factor ◽  
Test Results ◽  
Loading Test ◽  
Concrete Frame ◽  
Weak Beam ◽  
Bending Capacity ◽  
Column Joint

On the basis of the domestic and overseas scholars’ research, it is innovative to put forward a new precast frame beam-to-column connection. One full-scale beam-to-column connection in a precast concrete（PC）frame and a beam-to-column connection in a cast-in-place concrete structures were tested under uni-directional cyclic loading that simulated earthquake-type motions. The new-type beam-to-column joint in a precast concrete frame consisted of cast-in-place columns and precast beams. Test results showed that（a）The property and action of precast connections are similar to the cast-in-place connection, it showed that both precast connections and cast-in-place connection have similar seismic performance; (b) The cracking load of precast connection are similar to the cast-in-place connection; (c) All the columns of all specimens did not destroy, it illustrate that it conform to the strong column weak beam. (d) In this experiment test, because the control factor use the bending capacity of beam, it also play the same plastic hinge mechanism as the traditional component. All the longitudinal reinforcement destruction ahead of stirrup in beams, which should be confirmed the guiding ideology of strong shear weak bending. On the basis of the test results, design considerations for the beam-to column connection were recommended.

scholarly journals Development of Novel Connections for Pre-cast Composite and Pre-cast Concrete Frames

2015 ◽  
pp. 397-404
Author(s):  
J.D Nzabonimpa ◽  
Won-Kee Hong ◽  
Seon-Chee Park ◽  
Sunkuk Kim
Keyword(s):  
Precast Concrete ◽  
Steel Plates ◽  
Structural Elements ◽  
Structural System ◽  
Concrete Frames ◽  
Structural Behaviour ◽  
Moment Connections ◽  
Composite Frame ◽  
Structural Capacity ◽  
Cast Concrete

In some applications, the conventional steel pipe racks were encased with concrete to protect the frame from fire. However, the concrete encasing steel is not considered to contribute to structural capacity at all. This paper proposed pipe rack frames encased by precast concrete, but with functions both as a part of structural elements contributing to flexural load bearing capacity and to fire proofing. The new steel-concrete composite structural system consisting of steel, concrete with reinforcements, extended steel plates with bolts designed based on inelastic finite element method provides efficient structural performances, reducing material quantities with the protection from fires. Additionally extended plate with bolts introduced for column-beam joint assembly played important roles in providing moment connections. AISC 358 introduced the use of extended plate similar to the proposed connection. Significant experimental and analytical investigations were performed to verify structural behaviour of the composite frame. Material quantities were also compared to demonstrate economy of the new frames compared with conventional pipe rack frames.

Flexural Performance of U-Shaped Precast Concrete Beams with Non-Contact Lapped Splice

2008 ◽  
Vol 385-387 ◽  
pp. 349-352
Author(s):  
Sang Su Ha ◽  
Seung Hun Kim
Keyword(s):  
Precast Concrete ◽  
Internal Force ◽  
Reinforcing Bars ◽  
Flexural Performance ◽  
Analytical Work ◽  
Moment Resisting ◽  
Column Joint ◽  
Moderate Seismic Regions ◽  
Reinforcement Bar ◽  
Load Deflection Curve

In this study, new moment-resisting precast concrete beam-column joint is proposed for moderate seismic regions. The new joint includes the connection reinforcing bars, penetrated the joint and lap-spliced with the bottom bars of precast U-beam. To evaluate the performance for non-contact lapped splice, experimental and analytical work were conducted, for major variables of the length of lap and the diameter of connection reinforcing bars(D19, D22, and D25). Results of experimental and analytical works show that these variables have much influence on flexural strength and ductility, and deformation of lapped joint. Using nonlinear finite element method, analytic research was performed for investigating crack and fracture patterns, load-deflection curve, comparison of internal force, evaluation of ductility, stains of reinforcement bar.

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