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.

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

Buildings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 39
Author(s):  
Yanfei Shen ◽  
Yongqing Tu ◽  
Wei Huang
Keyword(s):  
Flexural Strength ◽  
Residential Buildings ◽  
Bending Moment ◽  
Approximate Expression ◽  
Confinement Effect ◽  
Appreciable Effect ◽  
Unified Theory ◽  
Interior Space ◽  
Cross Sectional ◽  
Composite Section

Concrete-filled steel tubular (CFST) members have been widely used in industrial structures and high-rise residential buildings. The multi-cell composite L-shaped concrete-filled steel tubular (ML-CFST) cross-section, as an innovative, special-shaped structural arrangement, may solve the issue of normal CFST members protruding from walls and result in more usable interior space. Currently, no design rules are available for the application of ML-CFST members. One of the primary objectives of the present study is to develop recommendations in line with the unified theory to evaluate the bending moment resistance of ML-CFST beams. According to the unified theory, the bending moment resistance of an ML-CFST beam is related to the compressive strength (fsc) and the flexural strength index (γm) of a composite section, in which the accuracy of γm and fsc are affected by a confinement effect factor (ξ). Nevertheless, the original expression of ξ is not suitable for ML-CFST sections, since the appreciable effect of the irregular shape on confinement is neglected. Considering the cross-sectional geometry and boundary conditions of the cells, an equivalent shape factor to modify the confinement effect was proposed in this study through dividing the infill concrete into highly confined areas and less confined areas. An adequate formula to calculate the fsc and an approximate expression of γm for the ML-CFST sections was then developed. Furthermore, four-point bending tests on eight specimens were carried out to investigate the flexural performance of the ML-CFST beams. Lastly, the proposed formulas were assessed against experimental and numerical results. The comparisons show that the proposed unified theory-based approach produced accurate and generally conservative results for the ML-CFST beams studied.

Flexural Behavior of Ferrocement Plates Incorporating Steel and PET Fibers

2015 ◽  
Vol 666 ◽  
pp. 97-106
Author(s):  
Comingstarful Marthong ◽  
Deba Kumar Sarma
Keyword(s):  
Flexural Strength ◽  
Energy Absorption ◽  
Volume Fraction ◽  
Flexural Behavior ◽  
Test Results ◽  
Slight Improvement ◽  
Variable Parameters ◽  
The Matrix ◽  
Negative Effect ◽  
Pet Fibers

Ferrocement plate with steel meshes incorporating fibers in an identical matrix were tested under bending. The main objective of the study was to investigate the effects of combining reinforcing steel meshes with discontinuous fibers as reinforcement in thin mortar matrix. The variable parameters were chosen as (a) number of mesh layers, single and double (b) the types of fiber i.e steel and polyethylene terephthalate (PET). Everything else being equal, the test results shows that addition of steel fibers to the matrix of ferrocement can effectively increase its flexural strength and energy absorption to failure. Cracking and spalling of mortar cover also significantly reduced. On the other hand, the contributions of same volume fraction of PET fibers are not significant compared to steel. However, addition of PET fibers control the early cracking of thin mortar and showed slight improvement in flexural strength and energy absorption to failure compared to control specimens. Reinforcing ferrocement plates incorporating steel or PET fibers is recommended for providing technical and economical advantages as no negative effect was observed.

scholarly journals FLEXURAL BEHAVIOR OF FRP BARS AFTER BEING EXPOSED TO ELEVATED TEMPERATURES

2021 ◽  
Vol 18 (1) ◽  
pp. 12-19
Author(s):  
Dr. Sherif El-Gamal ◽  
Abdulrahman M. Al-Fahdi ◽  
Mohammed Meddah ◽  
Abdullah Al-Saidy ◽  
Kazi Md Abu Sohel
Keyword(s):  
Flexural Strength ◽  
Elevated Temperatures ◽  
Flexural Modulus ◽  
Flexural Behavior ◽  
Test Results ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Significant Strength ◽  
Glass Frp ◽  
Frp Bars

This research study investigates the flexural behavior of fiber reinforced polymer (FRP) bars after being subjected to different levels of elevated temperatures (100, 200 and 300°C). Three types of glass FRP bars (ribbed, sand coated, and helically wrapped) and one type of carbon FRP bars (sand coated) were used in this study. Two testing scenarios were used: a) testing specimens immediately after heating and b) keeping specimens to cool down before testing. Test results showed that as the temperature increased the flexural strength and modulus of the tested FRP bars decreased. At temperatures higher than the glass transition temperature (Tg), significant flexural strength and modulus losses were recorded. Smaller diameter bars showed better residual flexural strength and modulus than larger diameter bars. The immediately tested bars showed significant strength and modulus losses compared to bars tested after cooling. Different types of GFRP bars showed comparable results. However, the helically wrapped bars showed the highest flexural strength losses (37 and 60%) while the sand coated bars showed the lowest losses (29 and 39%) after exposure to 200 and 300℃, respectively. The carbon FRP bars showed residual flexural strengths comparable to those recorded for the GFRP bars; however, they showed lower residual flexural modulus after being subjected to 200 and 300℃.

scholarly journals Experimental Study of Flexural Behavior of Reinforced Concrete Beam Strengthened with Prestressed Textile-Reinforced Mortar

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1137 ◽  
Author(s):  
Jongho Park ◽  
Sun-Kyu Park ◽  
Sungnam Hong
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Flexural Stiffness ◽  
Test Results ◽  
The Difference ◽  
Textile Reinforced Mortar

In this study, nine specimens were experimentally tested to analyze the strengthening efficiency of textile-reinforced mortar (TRM) and the difference in flexural behavior between prestressed and non-prestressed TRM-strengthened reinforced concrete beam. The test results show that TRM strengthening improves the flexural strength of TRM-strengthened reinforced concrete beams with alkali-resistant-(AR-) glass textile as well as that with carbon textile. However, in the case of textile prestressing, the strengthening efficiency for flexural strength of the AR-glass textile was higher than that of the carbon textile. The flexural stiffness of AR-glass textiles increased when prestressing was introduced and the use of carbon textiles can be advantageous to reduce the decreasing ratio of flexural stiffness as the load increased. In the failure mode, textile prestressing prevents the damage of textiles effectively owing to the crack and induces the debonding of the TRM.

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 A Study on the Flexural Behavior of Plain Cement Concrete with Self Compaction Concrete

2021 ◽  
Vol 9 (12) ◽  
pp. 441-447
Author(s):  
K. Srinivas
Keyword(s):  
Flexural Strength ◽  
Concrete Beams ◽  
The Self ◽  
Flexural Behavior ◽  
Test Results ◽  
Flexural Behaviour ◽  
Cement Concrete ◽  
Concrete Layer ◽  
Different Types

Abstract: To study the flexural behaviour of plain cement concrete with self-compaction concrete using three point loading. We are using two different types of concrete (Plain Cement Concrete and Self Compaction Concrete). For this we are using M20 grade concrete. We cast cubes and beams of sizes 150x150x150mm and 150x150x700mm respectively.Based on the test results it is concluded that the flexural strength of the self-compaction concrete beams is more than the plain cement concrete beams. And in the combination also the flexural strength is more when the plain cement concrete layer is at the bottom while the selfcompaction concrete layer is at top.

scholarly journals A Study on the Effect of Hollow Tubular Flange Sections on the Behavior of Cold-Formed Steel Built-Up Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Balaji Shanmugam ◽  
Manikandan Palanisamy ◽  
Paul O. Awoyera ◽  
Senthilnathan Chinnasamy ◽  
Mahalakshmi Subramaniam
Keyword(s):  
Flexural Strength ◽  
Failure Modes ◽  
Flexural Behavior ◽  
Test Results ◽  
Structural Members ◽  
Iron And Steel ◽  
Loading System ◽  
Failure Loads ◽  
Cold Formed Steel ◽  
The Web

This paper deals with a study conducted on flexural behavior of cold-formed steel built-up I-beams with hollow tubular flange sections. There were two types of test sections, namely, built-up sections that were assembled with either stiffened or unstiffened channels coupling back-to-back at the web and a hollow tubular rectangular flange at the top and bottom of the web to form built-up I-beam. The flexural behavior along with the strength and failure modes of the built-up sections was examined using the four-point loading system. Nonlinear finite element (FE) models were formulated and validated with the experimental test results. It was observed that the developed FE models had precisely predicted the behavior of built-up I-beams. Further, the verified FE models were used to conduct a detailed parametric study on cold-formed steel built-up beam sections with respect to thickness, depth, and yield stress of the material. The flexural strength of the beams was designed using the direct strength method as specified in American Iron and Steel Institute (AISI) for the design of cold-formed steel structural members and was compared with the experimental results and the failure loads predicted from FE models. Since the results were not conservative, a new customized design equation had been mooted and delineated in the study for determining the flexural strength of cold-formed steel built-up beams with hollow tubular flange sections.

Effect of Cross Sectional Shape of Polypropylene Fibers on Flexural Toughness of Composites and Fiber-to-Cement Matrix Adhesion

2013 ◽  
Vol 687 ◽  
pp. 485-489 ◽  
Author(s):  
Zahra Behdouj ◽  
Masoud Jamshidi ◽  
Masoud Latifi ◽  
Mana Halvaei
Keyword(s):  
Flexural Strength ◽  
Cross Section ◽  
Fiber Type ◽  
Flexural Behavior ◽  
Cement Matrix ◽  
Fiber Volume ◽  
Cross Sectional ◽  
Flexural Toughness ◽  
Pull Out ◽  
Sectional Shape

Cement based material are weak in flexure in comparison to compression. Fibers have been used for 100 years ago in an industrial process (i.e. Hatschek machine) to improve flexural and tensile strength of cement based materials. Many researches have been performed to define the best fiber condition such as fiber type, length, and diameter. A few investigations have been done on the effects of fiber cross section on fiber-cement bonding and flexural strength. In this research, polypropylene (PP) fibers which have diversity in cross section were selected and used as reinforcement in cementitious composites. Fibers characterized for cross sectional shape and average surface area. Flexural strength of the specimens at different fiber volume contents was evaluated. Also, the adhesion of the fibers (with different cross sections such as hollow, delta and circular) was measured using the pull-out test. Results showed that the cross section has an important effect on bonding of the fibers to cement matrix and flexural toughness of the specimens. It was observed that the hollow fiber that has the biggest lateral surface showed the highest pull-out load, and the delta fiber showed best flexural behavior.

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 An Investigation of Flexural Behavior of Pure and Hybrid Wood Composite Panels Using Weibull Analyses

2021 ◽  
Vol 72 (2) ◽  
pp. 201-210
Author(s):  
Abdurrahman Karaman ◽  
H. Ersen Balcioglu
Keyword(s):  
Flexural Modulus ◽  
Medium Density Fiberboard ◽  
Wood Products ◽  
Flexural Behavior ◽  
Composite Panels ◽  
Wood Composite ◽  
Furniture Industry ◽  
Test Results ◽  
Flexural Test ◽  
Distribution Method

The production of inexpensive wood products compared to their strength is important both in terms of economy and meeting the expectations of users. For this purpose, the use of hybrid wood products is increasing in the furniture industry. With the hybridization process, relatively cheap and flimsy material is combined with a material that has a stronger structure. Thus, stronger bonded material is manufactured cheaper. In this study, the flexural behavior of pure and hybrid wood composite panels, which were prepared by applying longitudinal jointing techniques from different wood materials, was investigated. In this context, pure chipboard, pure medium density fiberboard (MDF), chipboard-east beech and MDF-east beech hybrid wood composite panels were produced. During the hybridization process, oriental beech was combined by using the self-grooving technique in three different numbers as one row, two rows, and three rows. Flexural test results were analyzed according to the Weibull distribution method. The results of the analyses showed that the hybridization process increased the flexural strength and flexural modulus of pure wood panels by up to 214 %, and 95 %, respectively.

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