Dynamic behavior of concrete filled steel tubular columns

2019 ◽  
Vol 10 (2) ◽  
pp. 244-264 ◽  
Author(s):  
Said Hicham Boukhalkhal ◽  
Abd Nacer Touati Ihaddoudène ◽  
Luis Filipe Da Costa Neves ◽  
Wafa Madi
Keyword(s):  
High Performance ◽  
Research Work ◽  
Steel Frames ◽  
Steel Structures ◽  
Steel Tube ◽  
Absorption Capacity ◽  
Resistant Steel ◽  
Content Type ◽  
Open Section ◽  
Cfst Columns

Purpose The purpose of this paper is to investigate the static and dynamic inelastic response of rigid and semi-rigid connections of steel structures with concrete-filled steel tube (CFST) columns built in high seismic areas, and to compare it with those with open section columns. Design/methodology/approach CFST columns are frequently used in moment resistant steel frames located in seismic areas due to their inherent advantages, including their ductility, energy absorption capacity as well as their high bearing capacity. The smart combination of steel and concrete makes it possible to benefit from the advantages of both components to the maximum. This research work presents the nonlinear dynamic response of moment resistant steel frames with CFST columns, with rigid or semi-rigid connections, built in high seismic areas, according to the Algerian seismic code RPA 99/2003, European EC8 and American FEMA 356 to show the nonlinear characteristics of this type of structures, and their advantages over steel frames with open section columns. Findings The paper presents the advantages of using CFST columns with rigid and semi-rigid connections on the seismic response of portal steel frames. A high performance level in terms of ductility, plastic hinges distribution and their order of appearance has been obtained. It also shows the low effect of seismic loading on the structural elements with CFST columns compared to structures with open section columns. Originality/value The investigation of the numerical results has shown the possibility of their use in the seismic areas for their adequate performance, and also with respect to the design limits specified in the seismic guidelines. In addition, this study represents a first step to develop seismic performance factors for steel structures with CFST columns in Algeria, where the Algerian code do not include a comprehensive specification for the composite steel structures.

scholarly journals Behaviour of Basalt Fiber Reinforced Concrete Filled Mild Steel Tube

2018 ◽  
Vol 7 (4.2) ◽  
pp. 15
Author(s):  
Arunraj A ◽  
Ashwin Kumar J ◽  
Ajith J
Keyword(s):  
Reinforced Concrete ◽  
Testing Machine ◽  
Basalt Fiber ◽  
High Strength ◽  
Steel Tube ◽  
Absorption Capacity ◽  
Fiber Reinforced Concrete ◽  
Uniaxial Compression Test ◽  
Fiber Reinforced ◽  
Cfst Columns

The present study is an attempt to understand the behavior of concrete filled steel tubular column under uniaxial load. A concrete-filled steel tubular (CFST) column is formed by filling a steel tube with concrete. It is well known that concrete- filled steel tubular (CFST) columns are currently being used in the construction of buildings, due to their excellent static and earthquake-resistant properties, such as high strength, high ductility, large energy absorption capacity, bending stiffness etc. The external strengthening of using basalt fiber reinforced concrete material is emerging as a new trend in enhancing the structural performance concrete filled steel tubular members to counteract the drawbacks of the past rehabilitation work. In this project we are going to study about strength of the steel and concrete by doing compression strength, flexural strength, push out and uniaxial compression test. The tests are carried out with the help of universal testing machine. The readings are recorded and graphs are plotted.  

scholarly journals Axial load behaviour of steel tube columns in-filled with various high performance concretes

2021 ◽  
Author(s):  
Katie Chu
Keyword(s):  
Axial Load ◽  
High Performance ◽  
Failure Modes ◽  
Lightweight Concrete ◽  
High Strength ◽  
Crumb Rubber ◽  
Steel Tube ◽  
Axial Strength ◽  
Coarse Aggregates ◽  
Cfst Columns

This research concentrates on the axial load behaviour of circular, square and rectangular concrete filled steel tube (CFST) columns incorporating high-performance self-consolidating concretes such as ultra-high strength concrete (UHSC), engineered cementitious composite (ECC), lightweight concrete (LWC), and crumb rubber concrete (CRC). Seventy-four CFST specimens with varying slenderness, shape, concrete type and presence of internal bar reinforcements are tested experimentally under axial compression loading. The effect of these variables on axial load-deformation response, strain characteristics, failure modes, concrete confinement and axial strength are evaluated through experimental results. Performance of existing analytical/code based models for axial strength and concrete confined strength is evaluated. Concretes without coarse aggregates including UHSC proved less effective at enhancing axial strength of filled tube columns through confinement. In contrast, confinement in filled steel tube columns was found most effective with the use of concretes with coarse aggregates such as LWC and CRC.

Performance assessment of textile composite using NDE and mechanical testing techniques

2014 ◽  
Vol 5 (1) ◽  
pp. 17-29
Author(s):  
A. Saboktakin ◽  
T. Vu-Khanh
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Research Work ◽  
Textile Composites ◽  
Textile Composite ◽  
Destructive Testing ◽  
Content Type ◽  
Static Test ◽  
Testing Techniques ◽  
Inspection Techniques

Purpose – Quality assessment of textile composites needs to have sufficient knowledge about the various types of non-destructive testing techniques to detect defects as well as the effect of these defects on mechanical performance. The paper aims to discuss these issues. Design/methodology/approach – The major approach of this paper was to evaluate the potential of two inspection techniques named ultrasounds, vibrations for detecting textile reinforcement defects in composites and evaluate the composite performance in the presence of a damage. Findings – Potential solutions have been identified to solve the issue of signal attenuation observed during C-scan ultrasonic testing, and the criticality of initial defects on static test was determined. Originality/value – The research work presented here has been a first attempt to apply the combination of different techniques in particular polar scan for the textile composite inspection. This will become more crucial as requirements for high performance and complex shape textile composite parts.

scholarly journals Analysis of concrete-filled steel tubular columns after fire exposure

2018 ◽  
Author(s):  
Carmen Ibáñez ◽  
Luke Bisby ◽  
David Rush ◽  
Manuel L. Romero ◽  
Antonio Hospitaler
Keyword(s):  
Residual Strength ◽  
Steel Structures ◽  
Steel Tube ◽  
Load Level ◽  
Complete Analysis ◽  
Maximum Temperature ◽  
Sustained Load ◽  
Beam Model ◽  
Fire Response ◽  
Cfst Columns

Concrete filled steel tubular (CFST) columns have a high probability to resist high temperatures compared to steel structures, whose evaluation after a fire is limited by the resulting deformation. A better understanding of the behaviour of CFST columns after a fire, affected by the maximum temperature achieved by the concrete infill, is required to properly estimate their residual strength and stiffness in order to adopt a reasonable strategy with minimum post-fire repair. In this paper, a fiber beam model for the simulation of the post-fire response of slender concrete-filled steel tubular (CFST) columns is presented. First, the model is validated against experimental results and subsequently it is employed to analyse the post-fire response of circular CFST columns. The variation of the residual strength with the load level for realistic fire resistance times is numerically studied. Actually, in a building, the columns support load even while a fire is being extinguished, so it is important to take into account this loading condition when predicting the post-fire behaviour. Therefore, in this research, the complete analysis comprises three stages: heating, cooling and post-fire under sustained load conditions. The model considers realistic features typical from the fire response of CFST columns, such as the existence of a gap conductance at the steel-concrete interface or the sliding and separation between the steel tube and the concrete.

Feature based building orientation optimization for additive manufacturing

2016 ◽  
Vol 22 (2) ◽  
pp. 358-376 ◽  
Author(s):  
Yicha Zhang ◽  
Alain Bernard ◽  
Ravi Kumar Gupta ◽  
Ramy Harik
Keyword(s):  
Decision Making ◽  
Additive Manufacturing ◽  
High Performance ◽  
Research Work ◽  
Geometric Features ◽  
Content Type ◽  
Build Orientation ◽  
Multi Attribute Decision Making ◽  
Production Knowledge ◽  
Short Time

Purpose The purpose of this paper is to present research work based on the authors’ conceptual framework reported in the VRAP Conference 2013. It is related with an efficient method to obtain an optimal part build orientation for additive manufacturing (AM) by using AM features with associated AM production knowledge and multi-attribute decision-making (MADM). The paper also emphasizes the importance of AM feature and the implied AM knowledge in AM process planning. Design/methodology/approach To solve the orientation problem in AM, two sub-tasks, the generation of a set of alternative orientations and the identification of an optimal one within the generated list, should be accomplished. In this paper, AM feature is defined and associated with AM production knowledge to be used for generating a set of alternative orientations. Key attributes for the decision-making of the orientation problem are then identified and used to represent those generated orientations. Finally, an integrated MADM model is adopted to find out the optimal orientation among the generated alternative orientations. Findings The proposed method to find out an optimal part build orientation for those parts with simple or medium complex geometric shapes is reasonable and efficient. It also has the potential to deal with more complex parts with cellular or porous structures in a short time by using high-performance computers. Research limitations/implications The proposed method is a proof-of-concept. There is a need to investigate AM feature types and the association with related AM production knowledge further so as to suite the context of orientating parts with more complex geometric features. There are also research opportunities for developing more advanced algorithms to recognize AM features and generate alternative orientations and refine alternative orientations. Originality/value AM feature is defined and introduced to the orientation problem in AM for generating the alternative orientations. It is also used as one of the key attributes for decision-making so as to help express production requirements on specific geometric features of a desired part.

Investigations on prying forces in flexible connections of steel beams

2019 ◽  
Vol 10 (3) ◽  
pp. 415-424
Author(s):  
Radha Athipathi G. ◽  
Arunkumar C. ◽  
Umamaheswari N.
Keyword(s):  
Applied Load ◽  
Tensile Force ◽  
Plastic Hinge ◽  
Research Work ◽  
Analytical Calculation ◽  
Weld Line ◽  
Steel Structures ◽  
Content Type ◽  
Tensile Forces ◽  
Flexible Connections

Purpose The use of flexible connections throughout the steel structures provides a high level of stiffness compared to that of fully welded connections. Flexible connections allow for rotation to an extent, which make them perform better during earthquake than welded connections. In hanger connections, the applied load produces tension in the bolts and bolts are designed for tensile forces. When the deformation of the flange plate is equal to that of the bolts, a plastic hinge is formed in the flange plate at the weld line and the bolts are pulled to failure. If the attached plate is allowed to deform, additional tensile forces called prying forces are developed in the bolts. The paper aims to discuss these issues. Design/methodology/approach This paper includes the results of investigation on prying force in T-stub connection fabricated with normal grade bolts and high strength friction grip (HSFG) bolts. Finite element analysis has been carried out by creating models and analyzing the effect of external tensile force and bolt force. For different grades of bolt (4.6, 8.8, 10.9, 12.9), the prying force is calculated. Findings It is found that prying force is increasing with the change in grade of bolt used from normal to HSFG. The results obtained from analysis using IS 800:2007 codal provision are also included. It is observed that HSFG bolts do not allow for any slip between the elements connected and hence rigidity is increased. Originality/value The prying force mainly depends on geometrical parameter of the connection. In this research work, the variation of prying force was studied based on the variation in dimensions of T-stub angle section and bolt grade (4.6, 8.8, 10.9, 12.9). The method of obtaining prying force from bolt load and applied load is a unique approach. The results of FE analysis is validated with the analytical calculation as per IS 800:2007 code provisions, which shows the originality of the research.

scholarly journals Axial load behaviour of steel tube columns in-filled with various high performance concretes

2021 ◽  
Author(s):  
Katie Chu
Keyword(s):  
Axial Load ◽  
High Performance ◽  
Failure Modes ◽  
Lightweight Concrete ◽  
High Strength ◽  
Crumb Rubber ◽  
Steel Tube ◽  
Axial Strength ◽  
Coarse Aggregates ◽  
Cfst Columns

This research concentrates on the axial load behaviour of circular, square and rectangular concrete filled steel tube (CFST) columns incorporating high-performance self-consolidating concretes such as ultra-high strength concrete (UHSC), engineered cementitious composite (ECC), lightweight concrete (LWC), and crumb rubber concrete (CRC). Seventy-four CFST specimens with varying slenderness, shape, concrete type and presence of internal bar reinforcements are tested experimentally under axial compression loading. The effect of these variables on axial load-deformation response, strain characteristics, failure modes, concrete confinement and axial strength are evaluated through experimental results. Performance of existing analytical/code based models for axial strength and concrete confined strength is evaluated. Concretes without coarse aggregates including UHSC proved less effective at enhancing axial strength of filled tube columns through confinement. In contrast, confinement in filled steel tube columns was found most effective with the use of concretes with coarse aggregates such as LWC and CRC.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

Zn diffusion and reflow behaviour of Sn-9Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga solders on a Ni/Cu substrate under IR reflow

2014 ◽  
Vol 26 (2) ◽  
pp. 87-95 ◽  
Author(s):  
J. Mittal ◽  
K.L. Lin
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
Content Type ◽  
Diffusion Behavior ◽  
Zn Diffusion ◽  
Cu Substrate ◽  
Practical Applications ◽  
Substrate Interface ◽  
Solder Balls ◽  
Practical Implications

Purpose – This paper aims to compare the reflow and Zn diffusion behaviors in Sn-Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga (5E) solders during soldering on a Ni/Cu substrate under infrared (IR) reflow. The study proposes a model on the effect of various elements particularly Zn diffusion behavior in the solders on the formation of intermetallic compounds (IMCs). Design/methodology/approach – The melting activities of two solders near their melting points on copper substrates are visualized in an IR reflow furnace. Reflowed solder joints were analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy. Findings – Reflow behaviors of the solders are similar. During melting, solder balls are first merged into each other and then reflow on the substrate from top to bottom. Both solders show a reduced amount of Zn in the solder. Theoretical calculations demonstrate a higher Zn diffusion in the 5E solder; however, the amount of Zn actually observed at the solder/substrate interface is lower than Sn-9Zn solder due to the formation of ZnAg3 in the solder. A thinner IMC layer is formed at the interface in the 5E solder than the Sn-Zn solder. Research limitations/implications – The present work compares the 5E solder only with Sn-Zn solder. Additional research work may be required to compare 5E solder with other solders like Sn-Ag, SnAgCu, etc. to further establish its practical applications. Practical implications – The study ascertains the advantages of 5E solder over Sn-Zn solder for all practical applications. Originality/value – The significance of this paper is the understanding of the relation between reflow behavior of solders and reactivity of different elements in the solder alloys and substrate to form various IMCs and their influence on the formation of IMC layer at solder/substrate interface. Emphasis is provided for the diffusion behavior of Zn during reflow and respective reaction mechanisms.

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