scholarly journals Experimental study on the flexural behavior of large-scale rectangular concrete-filled steel tubular beams

2017 ◽  
Vol 10 (4) ◽  
pp. 895-905
Author(s):  
J. M. Flor ◽  
R. H. Fakury ◽  
R. B. Caldas ◽  
F. C. Rodrigues ◽  
A. H. M. Araújo
Keyword(s):  
Large Scale ◽  
Flexural Behavior ◽  
Test Results ◽  
Rigid Plastic ◽  
Moment Capacity ◽  
Hollow Section ◽  
And Performance ◽  
The Moment ◽  
Concrete Filling ◽  
Rectangular Tubes

ABSTRACT This paper presents a series of test results of large-scale rectangular concrete-filled steel tubular (CFST) beams to explore their performance under pure bending. Concrete-filling tests were initially carried out on two beam specimens of 12-m in length to investigate the feasibility of casting horizontally large-scale rectangular tubes. A total of six 6-m long specimens were subjected to flexural test afterward, including four CFST beams and two steel hollow section (SHS) beams for comparison. The test results showed that the rectangular CFST beams behaved in a relatively ductile manner. The concrete infilling enhanced the flexural behavior and performance of the steel tubes. Finally, the rigid-plastic theory showed suitable to predict the moment capacity of CFST compact beams.

scholarly journals Flexural Behavior of Steel Beam Strengthening by Prestressing Strands

2018 ◽  
Vol 7 (4.20) ◽  
pp. 572
Author(s):  
Dr. Mohammed M. Rasheed ◽  
Mr. Ali F. Atshan ◽  
Mr. Kamal Sh. Mahmoud
Keyword(s):  
Reference Beam ◽  
Flexural Behavior ◽  
Radius Of Curvature ◽  
Steel Beams ◽  
Steel Beam ◽  
Bottom Flange ◽  
Moment Capacity ◽  
External Prestressing ◽  
Prestressing Strands ◽  
The Moment

Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of the beams have the same steel section, clear span length and the strengthening samples which implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (815 MPa). From experimental results, it was found that the moment curvature curves behavior for the tested beams are stiffer and with less ductility than the reference beams and the ultimate moment capacity is increased with increasing the eccentricity location. While, the maximum radius of curvature at bottom flange decreases with increasing the eccentricity location as compare with the reference beam.   

Simplified calculation method for flexural moment capacity of cold-formed steel built-up section beams

2020 ◽  
Vol 23 (14) ◽  
pp. 3153-3167
Author(s):  
Xinmei Yao ◽  
Xuhong Zhou ◽  
Yu Shi ◽  
Yu Guan ◽  
Yuxuan Zou
Keyword(s):  
Calculation Method ◽  
Flexural Behavior ◽  
Moment Capacity ◽  
Failure Characteristics ◽  
Box Section ◽  
Cold Formed Steel ◽  
The Moment ◽  
Simplified Calculation ◽  
The Web ◽  
Simplified Calculation Method

Cold-formed steel built-up section beams are commonly employed in cold-formed steel framing owing to their excellent mechanical performance. In order to develop a simplified approach for obtaining the flexural moment capacity of built-up section beams, both experimental study and numerical analysis on the flexural behavior of cold-formed steel built-up I-section and box section beams under flexural load were carried out in this study. The I-section beams are assembled from two back-to-back cold-formed steel lipped channels, and the box section beams consist of a cold-formed steel plain channel overlapping a lipped channel. First, four-point bending tests were performed on 30 simply supported specimens having 10 different configurations, and the moment capacities and failure modes of built-up section beams at ultimate loads were investigated. The failure characteristics observed were the interaction of local and distortional buckling of the web and top flange for I-section beams and local buckling of the web and top flange in pure bending for box section beams. Then, finite element models were developed to simulate the tested specimens and validated against the experimental results in terms of the moment capacities and failure characteristics. Moreover, extensive parametric studies, including section height-to-width ratio and flange width-to-thickness ratio, were conducted with the validated numerical models to identify the key factors influencing built-up section beams. Finally, a simplified calculation method considering the reduction factor of the gross section modulus of the built-up section to predict the flexural moment capacities of cold-formed steel built-up I-section and box section beams was proposed.

scholarly journals Punching Shear Mechanism Based Design of Concrete-Filled CHS T-Joints under In-Plane Bending

2018 ◽  
Author(s):  
Fei Xu ◽  
Tak-Ming Chan ◽  
Ju Chen
Keyword(s):  
Failure Mode ◽  
Large Scale ◽  
Tube Wall ◽  
Fracture Initiation ◽  
Punching Shear ◽  
Composite Joints ◽  
T Joints ◽  
Moment Capacity ◽  
Hollow Section ◽  
Plane Bending

The in-plane bending behaviour of concrete-filled circular hollow section (CHS) T-joints was examined in this paper. The main failure mode, the punching shear of the chord-wall, was observed from the test of four large-scale joints with the diameter ratio of brace to chord (β) ranging from 0.44 to 0.85. The tube-wall deformation was measured to assess the governing failure mode of the composite joints. Complementary finite element (FE) methodology was verified against the experimental findings and the validated FE models were used to further investigate the mechanical behaviour and the design methodology. The feasibility to apply a fracture criterion in the material-level to a large-scale structural simulation was evaluated. The validated FE modes could successfully capture the tube-wall fracture initiation and propagation. Based on both experimental and numerical investigations, it was shown that the capacity of composite joints was governed by the ultimate strength limit, i.e. punching shear strength, due to the infill concrete that mitigated both inward and outward deformation on the compressive and tensile sides, respectively. The analytical model was established to reveal the composite actions between the tube and the inner concrete, and to elaborate the development of the flexural section-resistance. Finally, the design equation was proposed and could well predict the moment capacity. 

scholarly journals FCB system analysis and performance test results of 1000MW ultra supercritical coal fired power station

2021 ◽  
Vol 233 ◽  
pp. 04013
Author(s):  
Zhang Shuying ◽  
Li Lin ◽  
Zhang Cuihua ◽  
Gao Yan ◽  
Luan Tao
Keyword(s):  
Large Scale ◽  
Performance Test ◽  
System Analysis ◽  
Power Grid ◽  
Test Results ◽  
Power Station ◽  
Operation Conditions ◽  
Auxiliary Power ◽  
Short Period ◽  
And Performance

Fast cut back (FCB) function can make the power station restore the external power supply in a very short period of time from the auxiliary power operation conditions through self-help mode. In case of large-scale power grid failure, FCB further ensures the safety of the main equipments and bring great benefits for the rapid recovery of local power grid. Taking Taishan Power Plant 1000 MW unit as a research object, the feasibility scheme of adding FCB function was analyzed and demonstrated on the basis of making full use of the original equipment design margin. The FCB test of TMCR 100% load was completed. The test results and problems during FCB process were discussed, and the corresponding countermeasures were proposed.

The Effects on Screw Fasteners Spacing on Flexural Behavior and Strength Capacity of Cold-Formed Steel Built-Up Box Sections

2021 ◽  
Vol 26 (2) ◽  
pp. 163-173
Author(s):  
Maria Yasinta Menge Making ◽  
Ali Awaludin ◽  
Bambang Supriyadi
Keyword(s):  
Local Buckling ◽  
Flexural Behavior ◽  
Test Results ◽  
Lateral Torsional Buckling ◽  
Strength Capacity ◽  
Bending Capacity ◽  
Wing Width ◽  
Cold Formed Steel ◽  
The Moment ◽  
Buckling Distortion

The capacity and behaviour of cold-formed steel built-up sections are affected by the arrangement of the connections. This study aims to determine the effect of the screw spacing to the bending capacity and behaviour of the cold-formed steel built-up box section which made from lipped-channel (1.0 mm thick, 81 mm web height, 8.5 mm lip height, upper and lower wing width 38 mm and 40 mm). A total of 19 beams with a length of 1200 mm each are subjected to pure bending moments by applying two point loads spaced 600 mm in the midspan. The screw spacing variations in the moment span are 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 328 mm, and 350 mm. The test results show the average of bending capacity of the beam test is increasing with the reduction in screw spacing while the screw configuration also affects the beam capacity. Analysis of the bending capacity using the effective width method and the direct strength method based on AISI S100-16 gives very conservative results. The failure mode of the built-up box sections were observed in the form of local buckling, distortion, and lateral-torsional buckling. 

scholarly journals Experimental Flexural Behavior of Composite Beam using Cold Formed Hollow Square Section

2020 ◽  
Vol 9 (4) ◽  
pp. 1987-1992
Keyword(s):  
Composite Beam ◽  
Concrete Strength ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Test Results ◽  
Hollow Section ◽  
Lateral Strength ◽  
Composite Section ◽  
Flexural Tests ◽  
Hot Rolled

Structural hollow sections have excellent properties for resisting static loads, with regard to buckling, bi-axial bending and torsion. Structural hollow sections are generally used for truss components, considering greater stiffness and lateral strength. A square hollow section truss has about two third of surface area of same size I section. Hollow section truss may have smaller members as a result of higher structural efficiency. Construction of composite beam commonly includes I section. This paper deals with comparison of commonly used hot rolled or welded I composite section with cold formed hollow RHS and SHS composite section with respect to flexure and shear. Flexural tests were conducted to evaluate the structural behavior of the proposed composite beams. Two different steel sections were used for this study with nominal concrete strength of 30 MPa. The composite beams were tested under concentrated two points loading. The test results were plotted and compared with analytical results. The mid span deflections and slip were recorded for both composite beams. Buckling modes for both composite beams were identified. comparisons have been carried out between predicted beam strength as provided by Eurocode -4 and experimental test results. Sectional properties are checked for cold formed hollow square section using EN 1993-1-3.

scholarly journals Flexural Behavior of Double-Skin Steel Tube Beams Filled with Fiber-Reinforced Cementitious Composite and Strengthened with CFRP Sheets

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3064
Author(s):  
Ahmed Al-Nini ◽  
Ehsan Nikbakht ◽  
Agusril Syamsir ◽  
Nasir Shafiq ◽  
Bashar S. Mohammed ◽  
...  
Keyword(s):  
High Performance ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Moment Capacity ◽  
Cfrp Sheets ◽  
High Performance Fiber ◽  
Double Skin ◽  
The Moment

The concrete-filled double skin steel tube (CFDST) is a more viable option compared to a concrete-filled steel tube (CFST) due to consisting a hollow section, while degradation is enhanced simply by using carbon fiber-reinforced polymer (CFRP). Hence, the stabilization of a concrete’s ductile strength needs high- performance fiber-reinforced cementitious conmposite. This study investigates the behavior of high-performance fiber-reinforced cementitious composite-filled double-skin steel tube (HPCFDST) beams strengthened longitudinally with various layers, lengths, and configurtion of CFRP sheets. The findings showed that, with increased CFRP layers, the moment capacity and flexural stiffness values of the retrofitted HPCFDST beams have significantly improved. For an instant, the moment capacity of HPCFDST beams improved by approximately 28.5% and 32.6% when they were wrapped partially along 100% with two and three layers, respectively, compared to the control beam. Moreover, the moment capacity of the HPCFDST beam using two partial layers of CFRP along 75% of its sufficient length was closed to the findings of the beam with two full CFRP layers. For energy absorption, the results showed a vast disparity. Only the two layers with a 100% full length and partial wrapping showed increasing performance over the control. Furthermore, the typical failure mode of HPCFDST beams was observed to be local buckling at the top surface near the point of loading and CFRP rapture at the bottom of effect length.

scholarly journals Flexural Strength Evaluation of Multi-Cell Composite T-Shaped Concrete-Filled Steel Tubular Beams

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2838
Author(s):  
Yanfei Shen ◽  
Yongqing Tu
Keyword(s):  
Flexural Strength ◽  
Cross Section ◽  
Bending Moment ◽  
Flexural Behavior ◽  
Unified Theory ◽  
Test Results ◽  
Infill Wall ◽  
Distribution Method ◽  
Hollow Section ◽  
Effect Factor

The multi-cell composite T-shaped concrete-filled steel tubular (MT-CFST) element is an innovative structural form. It has great potential for construction applications because of favorable advantages over traditional composite elements. The flexural strength of MT-CFST beams was investigated in this study to provide recommendations in line with existing design codes. First, formulations to evaluate the flexural strength of MT-CFST beams were derived based on the Unified Theory and plastic stress distribution method (PSDM). For the Unified Theory-based formula, a modified confinement effect factor that considers the shape of a cross-section was proposed. An experimental study on the flexural behavior of six MT-CFST beams as well as two hollow section counterparts was conducted. The influence of bending moment direction, concrete infill, wall thickness, and cross-section sizes were investigated. The accuracy of the proposed formulations was verified against the test results and numerical results from finite element modeling. The comparisons showed that the formula in line with the Unified Theory provided more accurate predictions with reasonable conservatism for the studied MT-CFST beams.

Modified expression for the failure criterion of bucket foundations subjected to combined loading

2013 ◽  
Vol 50 (12) ◽  
pp. 1250-1259 ◽  
Author(s):  
K.A. Larsen ◽  
L.B. Ibsen ◽  
A. Barari
Keyword(s):  
Large Scale ◽  
Experimental Studies ◽  
Combined Loading ◽  
Vertical Load ◽  
Moment Capacity ◽  
Load Paths ◽  
Combined Loads ◽  
Loading Tests ◽  
The Moment ◽  
And Behavior

Recently, various loading tests with small- and large-scale bucket foundations were performed on buckets of varying sizes, embedment ratios, and load paths with saturated dense Aalborg University Sand No. 1 at the geotechnical laboratory of Aalborg University. In the present study, the capacity and behavior of bucket foundations subjected to combined loads were investigated on the basis of the results of these experimental studies. Although previous authors had proposed a linear relationship between the moment capacity and the vertical load, this relationship did not fit the observed capacities in the present study. Therefore, a modified expression is proposed to describe the combined capacity as a function of the tensile capacity and the inclination factor.

Experimental Study of Cold-Formed Steel Moment Connections with Screw Fasteners

2019 ◽  
Vol 950 ◽  
pp. 85-89
Author(s):  
Adeline Ling Ying Ng ◽  
Zhi Yong Law
Keyword(s):  
Local Buckling ◽  
Test Results ◽  
Moment Connections ◽  
Moment Capacity ◽  
Moment Connection ◽  
Steel Moment Connection ◽  
Steel Sections ◽  
Cold Formed Steel ◽  
The Moment ◽  
Hot Rolled

A series of connection with screw fasteners were tested to study the behavior of cold-formed steel moment connection. The test specimens included hot-rolled parallel flange channels, cold-formed lipped C-Channels, and self-drilling self-fastening screws. Two different lipped C-Channels and a various number of screws per connection were used in this study. The moment-rotation behavior, rotational rigidity, and the connection capacity differed with the number of screws. The connection behaved as a pinned connection when 4 screws were used. However, local buckling was observed in the cold-formed steel sections near the connection when 8, 10 and 14 screws were used. The connection test results were compared with theoretical results calculated in accordance to the Australian Standards. None of the connection tested could achieve the moment capacity of the section connected.

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