scholarly journals Ultimate Limit Design of Strengthened Steel Columns by Mortar-Filled FRP Tubes

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jian Hou ◽  
Li Song
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Load Capacity ◽  
Local Buckling ◽  
Ultimate Load Capacity ◽  
Composite Columns ◽  
Steel Columns ◽  
Frp Tube ◽  
Frp Tubes ◽  
Ultimate Limit

The present study investigated the various failure modes of strengthened steel columns by mortar-filled fiber-reinforced polymer (FRP) tubes to analytically formulate the ultimate capacities of these steel columns. A simple and effective method, wherein a mortar-filled FRP tube was sleeved outside the steel member, was also formulated to enhance the buckling resistance capacity of compressed steel members. In addition, to facilitate the connection of the column to other structural members, the length of the sleeved mortar-filled FRP tubes is less than that of the original steel columns. Theoretical analyses were also performed on the critical sections of such composite columns at their ultimate states to identify their potential failure modes, such as FRP-tube splitting at the ends or on the insides of wrapped areas, local buckling at the steel ends of transition zones, and global buckling of the composite columns. The corresponding ultimate capacity of each failure mode was then analytically formulated to characterize the critical failure mode and ultimate load capacity of the columns. The current theoretical results were compared with those from literature to validate the applicability of the developed ultimate limit design approaches for FRP-mortar-steel composite columns.

scholarly journals Experimental Study on the Effect of Heel Plate Length on the Structural Integrity of Cold-formed Steel Roof Trusses

2018 ◽  
Vol 65 ◽  
pp. 08010
Author(s):  
Je Chenn Gan ◽  
Jee Hock Lim ◽  
Siong Kang Lim ◽  
Horng Sheng Lin
Keyword(s):  
Ultimate Load ◽  
Structural Integrity ◽  
Load Capacity ◽  
Local Buckling ◽  
Ultimate Capacity ◽  
Ultimate Load Capacity ◽  
Plate Length ◽  
Roof Truss ◽  
Cold Formed Steel ◽  
Structural Failures

Applications of Cold-Formed Steel (CFS) are widely used in buildings, machinery and etc. Many researchers began the research of CFS as a roof truss system. It is required to increase the knowledge of the configurations of CFS roof trusses due to the uncertainty of the structural failures regarding the materials and rigidity of joints. The objective of this research is to investigate the effect of heel plate length to the ultimate load capacity of CFS roof truss system. Three different lengths of heel plate specimens were fabricated and subjected to concentrated loads until failure. The highest ultimate capacity for the experiment was 30 kN. The results showed that the increment of the length of the heel plate had slightly increased the ultimate capacity and strain. The increment of the length of the heel plate had increased the deflection of the bottom chords but decreased the deflection of the top chords. Local buckling of top chords adjacent to the heel plate was the primary failure mode for all the heel plate specimens.

Dynamic Response and Failure Mode Analysis on Light-Weight Steel Columns under Blast Loads

2012 ◽  
Vol 166-169 ◽  
pp. 1489-1497 ◽  
Author(s):  
Shi Yan ◽  
Lei Liu ◽  
Peng Li ◽  
Zhi Qiang Xin ◽  
Bao Xin Qi
Keyword(s):  
Dynamic Response ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Mode Analysis ◽  
Material Strength ◽  
Light Weight ◽  
Blast Loads ◽  
Element Analysis ◽  
Steel Columns

The dynamic response and failure mode of light-weight steel columns under blast loads were studied in this paper by using nonlinear finite element analysis (FEA) software ANSYS/ LS-DYNA, aiming to develop the degree and modes of the excessive plastic deformation during failures of the columns under diverse parameters. The damaged columns with initial blast-induced deformation may evidently influence vertical stability of light-weight steel frame structures. During the numerical simulation, the element of three dimensional solid SOLID164 was used, and the strain rate effect on material strength was included in the material model with Plastic-Kinematic (MAT-03). The main parameters included in the analysis were boundary conditions, scaled distances of explosions, and the vertical compressive load ratios applied on tops of the columns. The results showed that the column with both two fixed ends was the most beneficial to resist blast shock wave, the horizontal displacement at the middle span of the columns were obviously decreasing as increasing of the scaled distances of the explosion, and the axial compression ratio only significantly influenced the column with a sliding end. The failure modes of the developed columns may be summarized as bending failure, direct shear failure, and bending shear combination failure.

scholarly journals PERFORMANCE OF AXIALLY LOADED TAPERED CONCRETE-FILLED STEEL COMPOSITE SLENDER COLUMNS

2013 ◽  
Vol 19 (5) ◽  
pp. 705-717 ◽  
Author(s):  
Alireza Bahrami ◽  
Wan Hamidon Wan Badaruzzaman ◽  
Siti Aminah Osman
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Load Capacity ◽  
Special Kind ◽  
Nonlinear Analyses ◽  
Composite Columns ◽  
Finite Element Software ◽  
Tapered Angle ◽  
Steel Composite ◽  
Slender Columns

This paper focuses on the performance of a special kind of tapered composite columns, namely tapered concrete-filled steel composite (TCFSC) slender columns, under axial loading. These efficient TCFSC columns are formed by the increase of the mid-height depth and width of straight concrete-filled steel composite (CFSC) slender columns, that is, by the enhancement of the tapered angle (from 0° to 2.75°) of the tapered composite columns from their top and bottom to their mid-height. To investigate the performance of the columns, finite element software LUSAS is employed to carry out the nonlinear analyses. Comparisons of the nonlinear finite element results with the existing experimental results uncover the reasonable accuracy of the proposed modelling. Nonlinear analyses are extensively performed and developed to study effects of different variables such as various tapered angles, steel wall thicknesses, concrete compressive strengths, and steel yield stresses on the performance of the columns. It is concluded that increasing each of these variables considerably enhances the ultimate axial load capacity. Also, enhancement of the tapered angle and/or steel wall thickness significantly improves the ductility. Moreover, confinement effect of the steel wall on the performance of the columns is evaluated. Failure modes of the columns are also presented.

scholarly journals Experimental and Numerical Investigation into Failure Modes of Tension Angle Members Connected by One Leg

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5141
Author(s):  
Edyta Bernatowska ◽  
Lucjan Ślęczka
Keyword(s):  
Numerical Simulations ◽  
Failure Mode ◽  
Failure Modes ◽  
Experimental Testing ◽  
Load Capacity ◽  
Strength Function ◽  
Experimental Tests ◽  
Material Model ◽  
Design Standards ◽  
Element Analysis

This paper presents the results of experimental and numerical tests on angle members connected by one leg with a single row of bolts. This study was designed to determine which failure mode governs the resistance of such joints: net section rupture or block tearing rupture. Experimental tests were insufficient to completely identify the failure modes, and it was necessary to conduct numerical simulations. Finite element analysis of steel element resistance based on rupture required advanced material modelling, taking into account ductile initiation and propagation of fractures. This was realised using the Gurson–Tvergaard–Needleman porous material model, which allows for analysis of the joint across the full scope of its behaviour, from unloaded state to failure. Through experimental testing and numerical simulations, both failure mechanisms (net section and block tearing) were examined, and an approach to identify the failure mode was proposed. The obtained results provided experimental and numerical evidence to validate the strength function used in design standards. Finally, the obtained results of the load capacity were compared with the design procedures given in the Eurocode 3′s current and 2021 proposed editions.

Buckling analyses of double-shell octagonal lattice truss composite structures

2017 ◽  
Vol 52 (9) ◽  
pp. 1227-1237 ◽  
Author(s):  
Qianqian Sui ◽  
Changliang Lai ◽  
Hualin Fan
Keyword(s):  
Failure Mode ◽  
Composite Structures ◽  
Failure Modes ◽  
Local Buckling ◽  
Buckling Mode ◽  
One Dimensional ◽  
Load Carrying ◽  
Global Buckling ◽  
Buckling Failure ◽  
Equivalent Continuum

To reveal the compression failure modes of one-dimensional hierarchical double-shell octagonal lattice truss composite structures (DLTCSs), finite element modeling and equivalent continuum models were developed. DLTCS has three typical failure modes: (a) fracture of the strut, (b) global buckling, and (c) local buckling. Failure mode maps were constructed. It is found that column of long enough length will collapse at global buckling. When the column length decreases, the failure mode will turn to local buckling and strut fracture successively. Bay length greatly influences the buckling mode. Longer bay length could change the buckling mode from global buckling to local buckling. Compared with single-shell lattice truss composite structure, DLTCS has advantage in load carrying when the column fails at strut fracture or global buckling, while local buckling tolerance of DLTCS is smaller.

scholarly journals Effect of Number of Wire Mesh Layers and Depth Ratio on Ultimate Shear Force for Monopanel Beam Specimens

2017 ◽  
Vol 26 (1) ◽  
pp. 407-413
Author(s):  
Faris J. Al-Talqany
Keyword(s):  
Shear Force ◽  
Load Capacity ◽  
Local Buckling ◽  
Wire Mesh ◽  
Load Carrying Capacity ◽  
Ultimate Load Capacity ◽  
Steel Bar ◽  
Load Carrying ◽  
Steel Bars ◽  
Different Depths

A monopanel is the system building witch consists of two thin ferrocement block as a faces and  between them a bushy layer of low strength, density and cost as a core made from lightweight material for example from polystyrene foam as using in this investigation  or any material as an insulation . The simple structural idealization of a monopanel system is that the core provides transverse trusses between the faces that prevent flexural ,shear force and compression. Transverse trusses made of steel bars having a diameter of 3.2 mm, which make available as tie reinforcement to prevent the thin ferrocement skins from local buckling, have been used in the present work. These transfer system consist of two longitudinal bars connected by inclined steel bar forming trusses shape making an angle equals to 60o with the longitudinal bars. The main object of this research is to present an experimental investigation on the behavior and load carrying capacity of monopanel beams. The experimental work includes testing six groups of  monopanel beams, and has been investigated the effect of a different depths of monopanel beams and number of layer of wire mesh of skin faces (one or two layers )  on the behavior and the ultimate load capacity. Also comparison of these results with the ACI code 318M-08 formulations have been made.

scholarly journals Comparative Investigation on the Failure Modes of Natural Kenaf/Epoxy Reinforced Composite Hexagonal Tubes

2016 ◽  
Vol 709 ◽  
pp. 7-10 ◽  
Author(s):  
M.F.M. Alkbir ◽  
S.M. Sapuan ◽  
A.A. Nuraini ◽  
Mohamad Ridzwan Ishak
Keyword(s):  
Failure Mode ◽  
Transverse Crack ◽  
Failure Modes ◽  
Epoxy Composite ◽  
Local Buckling ◽  
Comparative Investigation ◽  
Composite Tubes ◽  
Reinforced Composite ◽  
Buckling Failure ◽  
Mode Response

This study aims to investigate failure mode response of woven natural kenaf/epoxy composite hexagonal tubes subjected to an axial and lateral quasi-static crushing test. The hexagonal composite tubes were prepared by the hand lay-up technique using a variety of hexagonal angles 40ο, 50 ο, and 60 ο. The result showed that hexagonal composite tubes under an axial compression test exhibited few failure modes such as, the transverse crack failure mode . Splaying failure mode and local buckling failure mode respectively, whereas the tubes under lateral test only exhibited longitudinal fracture.

scholarly journals Enhancing Stability of Thin-Walled Short Steel Channel Using CFRP under Eccentric Compression

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Hongyuan Tang ◽  
Canjun Wang ◽  
Ruijiao Wang
Keyword(s):  
Analytical Study ◽  
Ultimate Load ◽  
Load Capacity ◽  
Local Buckling ◽  
Fiber Reinforced Polymer ◽  
Actual Behavior ◽  
Thin Wall ◽  
Ultimate Load Capacity ◽  
Reinforced Polymer ◽  
Global Buckling

This paper presents the experimental and analytical results of eccentrically loaded short cold-formed thin-wall steel channels strengthened with transversely oriented carbon fiber reinforced polymer (CFRP) strips around their web and flange. Seven specimens, each 750 mm long, were fabricated; the main parameters were the number of CFRP plies (one or two) and the space between the CFRP strips (50, 100, or 150 mm). The application of the CFRP strips results in increases in ultimate load capacity and, with the exception of the most heavily reinforced (2 plies at 50 and 100 mm), local buckling was observed prior to global buckling. To extend and better understand the experimental work, a companion analytical study was conducted. Comparisons between experimental observations and computed results show that the analyses provided good correlation to actual behavior. In addition, the numerical results explained the observed phenomenon that flange local buckling was constrained to regions between the CFRP strips.

scholarly journals Mechanical Behavior and Failure Mode of Steel–Concrete Connection Joints in a Hybrid Truss Bridge: Experimental Investigation

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2549
Author(s):  
Yingliang Tan ◽  
Bing Zhu ◽  
Le Qi ◽  
Tingyi Yan ◽  
Tong Wan ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Failure Mode ◽  
Failure Modes ◽  
Local Buckling ◽  
High Strength ◽  
Testing Procedure ◽  
Gusset Plates ◽  
Truss Bridges ◽  
Study Results ◽  
Truss Bridge

The core part of a hybrid truss bridge is the connection joint which combines the concrete chord and steel truss-web members. To study the mechanical behavior and failure mode of steel–concrete connection joints in a hybrid truss bridge, static model tests were carried out on two connection joints with the scale of 1:3 under the horizontal load which was provided by a loading jack mounted on the vertical reaction wall. The specimen design, experimental setup and testing procedure were introduced. In the experiment, the displacement, strain level, concrete crack and experimental phenomena were factually recorded. Compared with the previous study results, the experimental results in this study demonstrated that the connection joints had the excellent bearing capacity and deformability. The minimum ultimate load and displacement of the two connection joints were 5200 kN and 59.01 mm, respectively. Moreover, the connection joints exhibited multiple failure modes, including the fracture of gusset plates, the slippage of high-strength bolts, the local buckling of compressive splice plates, the fracture of tensile splice plates and concrete cracking. Additionally, the strain distribution of the steel–concrete connection joints followed certain rules. It is expected that the findings from this paper may provide a reference for the design and construction of steel–concrete connection joints in hybrid truss bridges.

scholarly journals Retrofitting of shear strength self-compacting reinforced concrete deep beams with FRP

2018 ◽  
Vol 162 ◽  
pp. 04016
Author(s):  
Nabeel Al-Bayati ◽  
Bassman Muhammad ◽  
Sarah Sadkhan
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Ultimate Load ◽  
Load Capacity ◽  
Experimental Program ◽  
Deep Beams ◽  
Ultimate Load Capacity ◽  
Failure Loads ◽  
Effective Depth ◽  
Midspan Deflection

Experimental program were carried out to investigate the behavior of self-compacting reinforced concrete deep beams retrofitting with carbon fiber reinforced polymer (CFRP). Six simply supported deep beams were tested under symmetrically two point loads, three beams were tested up to failure without strengthening as a control beams with different shear span to effective depth ratio (a/d) while the other two beams were loaded up to 60% from the ultimate load of control beams for each a/d ratio and then retrofitted by the same configuration of CFRP to study the effect of a/d ratio on the properties of deep beams retrofitted. a/d for tested beams were (0.8, 1, 1.2). Study was focused on determining failure loads, cracking loads, failure modes, load midspan deflection. All the beams had the same compressive strength, overall dimensions and flexural and shear reinforcement. It was concluded that using this retrofitted method is very efficient and a gain in the ultimate load capacity of the deep beams was obtained also the results showed that when a/d ratio increase from 0.8 to 1.2, the ultimate load was decrease by 25% and midspan deflection was increased approximately at all load stages for control and retrofitted beams.

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