scholarly journals Numerical Study on Cyclic Response of End-Plate Biaxial Moment Connection in Box Columns

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 523 ◽  
Author(s):  
Marco Gallegos ◽  
Eduardo Nuñez ◽  
Ricardo Herrera
Keyword(s):  
Failure Mechanism ◽  
Axial Load ◽  
Numerical Study ◽  
Seismic Action ◽  
Moment Frames ◽  
Cyclic Response ◽  
Tubular Columns ◽  
Moment Connection ◽  
Endplate Connection ◽  
Box Columns

The 2008 Wenchuan-China earthquake showed the importance of considering the bidirectional seismic action as a cause of failure in column hinge mechanisms. Subsequently, the large 2011 Tohoku-Japan earthquake revealed that Special Moment Frames buildings, made of tubular columns (Hollow Structural Section or Built-up Box Section) and rigid connections with I-beams, did not suffer serious damage. However, only the ConXtech® ConXL™ moment connection has been prequalified according to the (American Institute of Construction) AISC Seismic Provisions for use with tubular columns and the rest of connections do not consider biaxial resistance. The research reported herein investigated the cyclic response of box-columns joints, connected to I beams using the four-bolt extended endplate connection, subjected to bidirectional bending and axial load on the column. To conduct the study, complex nonlinear finite element models (FEMs) of several I beam to box column joint configurations were constructed and analyzed under cyclic loading using the ANSYS software. The results reveal that the failure is concentrated in the beams of all joint configurations except for the columns with axial load equal to 75% of the column capacity, where a combined failure mechanism is achieved. The energy dissipation capacity of joints with a greater number of beams is lower than joints with fewer beams. The bidirectional effect of the seismic action and the level of axial load must be considered to avoid the formation of a column-hinge fragile failure mechanism also the behavior exhibited by 3D joints is more realistic than 2D joints according to real structures.

scholarly journals Cyclic Performance of End-Plate Biaxial Moment Connection with HSS Columns

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1556
Author(s):  
Eduardo Nuñez ◽  
Roberto Lichtemberg ◽  
Ricardo Herrera
Keyword(s):  
Seismic Performance ◽  
Failure Modes ◽  
Numerical Study ◽  
Ductile Failure ◽  
Dissipated Energy ◽  
Moment Frames ◽  
End Plate ◽  
Panel Zone ◽  
Moment Connection ◽  
Hollow Structural Section

This paper presents a numerical study on the seismic performance of end-plate moment connection between I-beam to HSS (hollow structural section) column stiffened by outer diaphragms (EP-HSS). In previous experimental research, this moment connection showed a satisfactory performance according to requirements established in Seismic provisions. However, one type of joint was studied and bidirectional and axial loads were not considered. In this since, several configurations representative of 2D interior joints and 3D interior and exterior joints in a steel building were modeled and subjected to unidirectional or bidirectional cyclic displacements according to protocol in seismic provisions. Firstly, a similar joint configuration was calibrated from experimental data, obtaining an acceptable adjustment. The assessment of seismic performance was based on hysteretic curves, failure mechanisms, stiffness, dissipated energy, and equivalent damping. The results obtained showed a ductile failure modes for 2D and 3D joint configurations with EP-HSS moment connection. The axial load has no significant effect on the moment connection. However, it affects the column strength due to the increase of the stresses in the column wall. Compared with 2D joints, 3D joints reached higher deformations even when a similar number of beams is used. The external diaphragms to the column panel zone provided rigidity in the joints and no degradation of slope for each loop in load/reload segment for elastic loop; therefore, curves without pinching were observed. All inelastic deformation is concentrated mainly in the beams. A moment resistance above 80% of the capacity of the beam at a drift of 4% is achieved in all joints. From the results reached, the use of EP-HSS moment connection with hollow structural section columns is a reliable alternative in seismic zones when steel moment frames are employed.

scholarly journals Numerical study of concrete-filled aluminium alloy tubular columns under eccentric compression

2021 ◽  
Vol 1058 (1) ◽  
pp. 012010
Author(s):  
Shafayat Bin Ali ◽  
George S. Kamaris ◽  
Michaela Gkantou ◽  
Kunal Kansara ◽  
Khalid Hashim
Keyword(s):  
Aluminium Alloy ◽  
Numerical Study ◽  
Tubular Columns ◽  
Eccentric Compression

Experimental Investigation of Stiffened Square CFST Columns under Axial Load

2014 ◽  
Vol 919-921 ◽  
pp. 1794-1800
Author(s):  
Xin Zhi Zheng ◽  
Xin Hua Zheng
Keyword(s):  
Experimental Investigation ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Axial Load ◽  
Local Buckling ◽  
Test Results ◽  
Tubular Columns ◽  
Economical Benefit ◽  
Steel Consumption ◽  
Cfst Columns

Abstract: 7 square steel tubular columns were tested to discuss the ultimate axial bearing capacity, ductility performance and the steel consumption under stiffened by steel belts and binding bars of different cross-sections. Test results indicate that only by increasing fewer amounts of steel usage, stiffened square CFST columns with binding bars can not only improve the overall effects of restraint and alleviate regional local buckling between the binding bars, but also improve the bearing capacity of concrete filled square steel tubular columns. The utility benefits and the economical benefit is considerable, deserving extensive use.

scholarly journals Plastic hinge location in columns of steel frames subjected to seismic actions

2008 ◽  
Vol 41 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Brian H. H. Peng ◽  
Gregory A. MacRae ◽  
Warren R. Walpole ◽  
Peter Moss ◽  
Rajesh Dhakal ◽  
...  
Keyword(s):  
Axial Force ◽  
Plastic Hinge ◽  
Time History ◽  
Steel Structure ◽  
Braced Frames ◽  
Moment Frames ◽  
Eccentrically Braced Frames ◽  
Moment Connection ◽  
History Analysis ◽  
Active Link

Several steel structure standards around the world contain an equation to encourage any column flexural yielding during earthquake shaking to occur at the column ends, rather than along the column length. The accuracy of these equations and their applicability to columns of both moment frames and braced frames are examined in this paper. It is shown, using an analytical procedure developed from first principles considering the reduction in member stiffness from axial force due to geometric and material nonlinearity, that the existing code equations are conservative. Less conservative empirical equations are developed based on the analysis results. It is found that these equations are applicable to frames with a braced connection, rather than a moment connection into the column. Time-history analysis of eccentrically-braced frames with inverted V-bracing, where the active link occurs at the centre of the beam, is carried out. The likely column end moment ratio needed for the new equations is determined. The analysis also shows that yielding often did not occur in the bottom story columns during earthquake excitations. A simple check is proposed to relate the axial force limit and the design drift to flexural yielding of columns which can be used in conjunction with the proposed equations.

Application of Fracture Mechanics to Steel Connections in Moment Frames under Seismic Loading

1997 ◽  
Vol 1 (1) ◽  
pp. 23-37 ◽  
Author(s):  
C. Joh ◽  
W.F. Chen
Keyword(s):  
Fracture Mechanics ◽  
Steel Structures ◽  
Northridge Earthquake ◽  
Moment Frames ◽  
Moment Connections ◽  
Related Factors ◽  
Steel Connections ◽  
Moment Connection ◽  
San Fernando ◽  
The Moment

The 6.8 magnitude Northridge earthquake that shook California's San Fernando Valley on January 17 in 1994, did not cause the collapse of any steel structures but connections, confidently designed and constructed in the past with traditional code simplification and common site welding techniques, were discovered not to meet our expectations. This paper reviews connection failures during the 1994 Northridge earthquake and the design philosophy and examines the post-Northridge earthquake experimental and analytical researches. Possible causes of the moment connections damage are categorized into three classes; welding-related factors, design-related factors, and material-related factors. For the analyses, the idealizations of the moment connection considering each factor are studied. From the idealization of the moment connection, the five-plate model is analyzed to investigate the stress concentration and stress state of the connection. The equivalent design crack models are investigated using the fracture mechanics approach.

SEISMIC PERFORMANCE OF GFRP-RC RECTANGULAR COLUMNS: NUMERICAL STUDY

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ehab El-Salakawy ◽  
Fangxin Ye ◽  
Yasser Mostafa Selmy
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Axial Load ◽  
Numerical Study ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Concrete Columns ◽  
Load Level ◽  
Reinforced Concrete Columns ◽  
Rectangular Columns

Composite materials like glass fiber-reinforced polymer (GFRP) is becoming widely acceptable to be used as a reinforcing material due to its high ultimate tensile strength-to-weight ratio and excellent resistance to corrosion. However, the seismic behavior of GFRP-reinforced concrete columns has not been fully investigated yet. This paper presents the results of a numerical analysis of full-size GFRP-RC rectangular columns under cyclic loading. The simulated column depicts the lower part of a building column between the foundation and the point of contra-flexure at the mid-height of the column. GFRP reinforcement properties and concrete modeling based on fracture energy have been incorporated in the numerical model. Experimental validation has been used to examine the accuracy of the constructed finite element models (FEMs) using a commercially available software. The validated FEM was used to perform a parametric study, considering several concrete strength values and axial load levels, to study its influence on the performance of the GFRP-reinforced concrete columns under cyclic loading. It was concluded that the hysteretic dissipation capacity deteriorates under high axial load level due to severe softening of the concrete. The FE results showed a substantial improvement of the lateral load-carrying capacities by increasing concrete compressive strength.

Numerical Study on Seismic Behavior of Composite Shear Walls with Steel-Encased Profiles Subjected to Different Axial Load

2021 ◽  
Vol 26 (4) ◽  
pp. 04021034
Author(s):  
Amirhoshang Akhaveissy ◽  
Kambiz Daneshvar ◽  
Dina Ghazi-Nader ◽  
Morteza Amooie ◽  
Mohammad Javad Moradi
Keyword(s):  
Axial Load ◽  
Seismic Behavior ◽  
Numerical Study ◽  
Shear Walls ◽  
Composite Shear
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