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bending-strength
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, M.Sc. Thesis Sharif University of Technology ; Moghaddam, Hassan (Supervisor)
Abstract
The paper presents the results nonlinear analysis of steel base plates subjected to different combinations of axial and bending forces. The bending forces range from small moments representing small eccentricities to large moments from seismic actions. The results of analyses proved to be in good agreement with experiments. The parameters investigated in this study are as follows: distribution of strain and stresses in the concrete foundation and the steel plate, the strains and stresses in the tensile anchorage bolts, the location of neutral curve under the base plate, the centre of compressional reaction forces in concrete, the flextural rigidity of the base plate connection, and the axial...
Synthesis of Magnesium Aluminate Spinel Nanoparticles Using Chemical Method and Investigation of the Effect of Zirconia on Spinel Composites Properties
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor)
Abstract
In this research, a powder containing magnesium-aluminate spinel particles is prepared based on co-precipitation method and 5% , 10%, 15% and 20% zirconia-contained composites are produced as second phase from the synthesized powder. The raw materials used in the synthesis comprise hexa-hydrated magnesium nitrate, nona-hydrated aluminum nitrate, ammonium bicarbonate, 28% ammonium solution and distilled water. The properties of the powder is then investigated using STA, XRD and SEM tests. Also, XRD and SEM analyses as well as triple point flexural strength and Vickers hardness tests are carried out in order to investigate the effect of adding zirconia to the powders. The variations of the...
Investigation on Nonlinear Behavior of base Plates with Triangular Hardener under Axial Load and Bending Moment
, M.Sc. Thesis Sharif University of Technology ; Moghaddam, Hassan (Supervisor)
Abstract
The paper presents the results of nonlinear analysis of steel base plates subjected to different combinations of axial and bending forces. The bending forces range from small moments representing small eccentricities to large moments from seismic actions. The results of nonlinear analysis are done on three samples of the column base plate with large moment, small moment and compression axial force are compared to the results of the code. The parameters investigated in this study are as follows: distribution of strain and stresses in the concrete foundation and the steel plate, the strains and stresses in the tensile anchorage bolts, the location of neutral curve under the base plate, the...
The Investigation of Additive Elements Ti, Cr on Structure and Some Mechanical Properties of Micro and Nano Composites of Iron Aluminide/Alumina
, M.Sc. Thesis Sharif University of Technology ; Abachi, Parvin (Supervisor) ; Salahi, Esmaeil (Supervisor)
Abstract
In this experiment, first the Fe and Al powders with atomic ratio of 25 and 75 were mixed by mechanical alloying process. After obtaining the optimum conditions of milling, nano structural Fe3Al powder was synthesized by 40 hours alloying with a Ball to Powder Ratio (BPR) of 20:1. The synthesized powder was then milled with different weight ratios of titanium and Cr for 30 hours. Morphological changes, size of powder particles, lattice strain, grain size and phase transitions were studied for different powders in different time spans during milling process by means of scanning electron microscopy, X-ray diffraction and grain size analyzer. The smallest grain size gained for milled powder...
Green high strength concrete containing recycled waste ceramic aggregates and waste carpet fibers: Mechanical, durability, and microstructural properties
, Article Journal of Building Engineering ; Volume 26 , 2019 ; 23527102 (ISSN) ; Ameri, F ; Bahrami, N ; Shoaei, P ; Musaeei, H. R ; Nurian, F ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This paper investigated the combined utilization of recycled waste ceramic aggregate (RWCA) and waste carpet fibers (WCFs) in high strength concrete (HSC). Concrete mixes containing different percentages of RWCA including 20%, 40%, 60% (by weight) as partial replacement of natural coarse aggregate (NCA) were prepared. To enhance the tensile and flexural strength of concrete, 1.0% (by volume) WCF was added to the mixes. The slump and density of the fresh concrete were evaluated, both of which demonstrated a decreasing trend with incorporation of RWCA and WCF. With regard to the hardened concrete, replacing 40% of NCA with RWCA led to the optimum mechanical properties and increased the...
Investigation of hydroelastic effect in analysis of high-speed craft
, Article Ships and Offshore Structures ; Volume 11, Issue 1 , 2016 , Pages 16-24 ; 17445302 (ISSN) ; Seif, M. S ; Tabeshpur, M. R ; Yaakob, O ; Sharif University of Technology
Taylor and Francis Ltd
2016
Abstract
Hydroelastic effect in bottom slamming problem of high-speed craft is one of the most challenging issues in structural design. In this paper, numerical method is used to investigate the hydroelastic effect in bottom-water impact analysis of high-speed monohull craft. Slamming with two viewpoints of rigid and elastic structures (hydroelastic effect) is modelled by coupled computational fluid dynamic (CFD) and finite element method (FEM) techniques. The results showed that considering hydroelastic effect, especially in high-impact speed, reduces the structural deformations and stresses compared with quasi-statistic analysis. The effect of different parameters, such as boundary condition, plate...
Behavior of polymer concrete beam/pile confined with CFRP sleeves
, Article Mechanics of Advanced Materials and Structures ; 2017 , Pages 1-8 ; 15376494 (ISSN) ; Toufigh, V ; Saadatmanesh, H ; Ahmari, S ; Kabiri, E ; Sharif University of Technology
Abstract
This research investigates the flexural behavior of a polymer concrete beam/pile encased with carbon fiber sleeve. The mechanical properties of carbon fiber sleeves in tension and cement and polymer concrete in compression were determined. Polymer concrete beams were tested in flexure to determine the bending moment capacity. Then, the test results were compared to the theoretical model results. Finally, a parametric study was conducted to determine the influence of beam/pile parameters on the capacity of the element. Based on the investigation, carbon fiber sleeve filled with polymer concrete exhibits outstanding structural performance including ductility and bending capacity. © 2017 Taylor...
Behavior of polymer concrete beam/pile confined with CFRP sleeves
, Article Mechanics of Advanced Materials and Structures ; Volume 26, Issue 4 , 2019 , Pages 333-340 ; 15376494 (ISSN) ; Toufigh, V ; Saadatmanesh, H ; Ahmari, S ; Kabiri, E ; Sharif University of Technology
Taylor and Francis Inc
2019
Abstract
This research investigates the flexural behavior of a polymer concrete beam/pile encased with carbon fiber sleeve. The mechanical properties of carbon fiber sleeves in tension and cement and polymer concrete in compression were determined. Polymer concrete beams were tested in flexure to determine the bending moment capacity. Then, the test results were compared to the theoretical model results. Finally, a parametric study was conducted to determine the influence of beam/pile parameters on the capacity of the element. Based on the investigation, carbon fiber sleeve filled with polymer concrete exhibits outstanding structural performance including ductility and bending capacity
Experimental study of RC jacketed and CFRP strengthened RC beams
, Article Construction and Building Materials ; Volume 95 , October , 2015 , Pages 476-485 ; 09500618 (ISSN) ; Sedehi, O ; Khaloo, A ; Raisi, E. M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
This paper presents the results of an experimental study on retrofitting RC beams using FRP strengthening and RC jacketing. Three-point loadings are applied to twelve strengthened beams and three reference specimens to put the two techniques into perspective. Formation of first cracks, FRP debonding, and onset of concrete crushing are compared and discussed. Load-deflection behavior, failure modes, and crack propagation patterns are studied extensively. The experiments demonstrate that the RC jacketed beams exhibit a flexural failure identical to the reference beams. However, the FRP strengthened beams fail in a relatively small deflection due to the premature FRP debonding. Furthermore, the...
Comparative study on the effect of fiber type and content on the fire resistance of alkali-activated slag composites
, Article Construction and Building Materials ; Volume 288 , 2021 ; 09500618 (ISSN) ; Ghassemi, P ; Ameri, F ; Musaeei, H. R ; Chee Ban, C ; Ozbakkaloglu, T ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Alkali-activated slag (AAS) binder has been recognized as a suitable material for construction applications owing to its low carbon footprint and good mechanical and durability performance. As a promising alternative to the conventional Portland cement binder, it is important to maximize the performance of AAS composites under normal and harsh environmental conditions such as exposure to fire. The use of fibers in a brittle matrix is a well-known approach to enhance the mechanical strength and cracking behavior under thermal loading. In this study, polypropylene fiber (PPF), glass fiber (GF), and basalt fiber (BF) are used at volume fractions of 0.5%, 1%, and 1.5% in AAS mortar mixes. First,...
Flexural-torsional behavior of thin-walled composite beams with closed cross-section
, Article Thin-Walled Structures ; Volume 45, Issue 7-8 , 2007 , Pages 699-705 ; 02638231 (ISSN) ; Haddadpour, H ; Kouchakzadeh, M. A ; Sharif University of Technology
2007
Abstract
This paper investigates the static and dynamic characteristics of composite thin-walled beams that are constructed from a single-cell box. The structural model considered herein incorporates a number of nonclassical effects, such as material anisotropy, transverse shear, warping inhibition, nonuniform torsional model and rotary inertia. The governing equations were derived using extended Hamilton's principle and solved using extended Galerkin's method. The effects of fiber orientation on static deflection and natural frequencies are considered and a number of important conclusions are outlined. © 2007 Elsevier Ltd. All rights reserved
The effect of mixing molar ratios and sand particles on microstructure and mechanical properties of metakaolin-based geopolymers
, Article Materials Chemistry and Physics ; Volume 240 , 2020 ; Nemati, A ; Khodabandeh, A. R ; Baghshahi, S ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this study the influence of the molar ratios such as SiO2:Al2O3:Na2O:H2O, as well as the sand particles on the mechanical performance, shrinkage and microstructure of metakaolin based geopolymers was studied. Considering different content of the reactive silica and alumina in metakaolin, forty eight different compositions were prepared. The proper condition for achieving the highest mechanical performance as well as less structural defects by tailoring the curing condition, molar ratios and addition of sand particles are presented. Special attention was paid to the incorporation of sand particles up to 70 wt% on the microstructure, shrinkage and mechanical properties of metakaolin based...
Investigating the effect of heat treatment on the fracture toughness of a hot extruded Al–Ti composite produced by powder metallurgy route
, Article Materials Science and Engineering A ; Volume 771 , 2020 ; Madaah Hosseini, H. R ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
An Al-5 wt% Ti composite was fabricated via powder metallurgy technique and hot extrusion. The produced composite samples were heat-treated subsequently at 600 °C for various time durations of 0, 4 and 10 h to achieve different volume fractions of the intermetallic Al3Ti phase. Pure aluminum sample was produced as a benchmark specimen to be compared to the composite samples. SEM studies were used to investigate the microstructure of the composite samples, and it was revealed that core-shell structured particles were formed in the composite heat-treated for 4 h. Triple point bending test was performed on the single edge notched beam specimens of the heat-treated Al-5 wt% Ti composite and the...
Rubberized alkali-activated slag mortar reinforced with polypropylene fibres for application in lightweight thermal insulating materials
, Article Construction and Building Materials ; 2020 ; Shoaei, P ; Shariati, M ; Ameri, F ; Musaeei, H. R ; Behforouz, B ; de Brito, J ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Every year, about a thousand million tires reach the end of their service life, more than half of which are disposed of in landfills. The waste tire rubber has a great potential for application as aggregate phase in production of lightweight concrete/mortar. This study is aimed at evaluating the effects of using crumb rubber (CR) as fine aggregate at replacement ratios of 0–60% (by volume) in alkali-activated slag mortars. Furthermore, polypropylene fibre (PPF) was used at 0.5% and 1% of volume of the mix to enhance the properties of mortar mixes such as flexural strength and shrinkage behaviour. The compressive strength, flexural strength, water absorption, thermal conductivity, drying...
Rubberized alkali-activated slag mortar reinforced with polypropylene fibres for application in lightweight thermal insulating materials
, Article Construction and Building Materials ; Volume 270 , 2021 ; 09500618 (ISSN) ; Shoaei, P ; Shariati, M ; Ameri, F ; Musaeei, H. R ; Behforouz, B ; de Brito, J ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Every year, about a thousand million tires reach the end of their service life, more than half of which are disposed of in landfills. The waste tire rubber has a great potential for application as aggregate phase in production of lightweight concrete/mortar. This study is aimed at evaluating the effects of using crumb rubber (CR) as fine aggregate at replacement ratios of 0–60% (by volume) in alkali-activated slag mortars. Furthermore, polypropylene fibre (PPF) was used at 0.5% and 1% of volume of the mix to enhance the properties of mortar mixes such as flexural strength and shrinkage behaviour. The compressive strength, flexural strength, water absorption, thermal conductivity, drying...
Experimental study of the effect of water to cement ratio on mechanical and durability properties of Nano-silica concretes with Polypropylene fibers
, Article Scientia Iranica ; Volume 26, Issue 5 A , 2019 , Pages 1-18 ; 10263098 (ISSN) ; Ghaemian, M ; Hosseini, S. A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
In the present paper, the effect of Nano silica on mechanical properties and durability of concrete containing polypropylene fibers has been investigated. Here, the length and length to diameter ratio of used polypropylene fibers were considered to be fixed and equal to 18 mm and 600 respectively and the cement content was 479 kg/m3. The effect of fibers and Nano silica in four different percentages for each one at 0.1, 0.2, 0.3 and 0.4 percent by volume for fibers and 3 percent for Nano silica in concrete with water to cement ratio of 0.33, 0.36, 0.4, 0.44 and 0.5 have been compared and evaluated. In total, more than 425 cubic and cylindrical specimens were made according to ASTM standards....
Effect of SiO2 content on Y-TZP/Al2O3 ceramic-nanocomposite properties as potential dental applications
, Article Ceramics International ; Volume 46, Issue 8 , 2020 , Pages 10910-10916 ; SharifianJazi, F ; Esmaeilkhanian, A ; Moradi, M ; Safi Samghabadi, A. H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) have been widely applied in fixed partial prostheses as well as dental uses i.e. a substructure for crowns. However, Y-TZP has limited applications, which is due to the presence of defects in its microstructure introduced during the manufacturing process. Accordingly, due to Y-TZP limitations, the novel (X)Y-TZP- 20Al2O3-(80-X) SiO2 (X = 65, 70 and 75) ceramic nanocomposites were successfully fabricated via the powder metallurgy method. X-ray diffraction (XRD) patterns of commercial powders showed the stabilization of monoclinic zirconia (ZM) by increasing the silica content. In order to determine the fracture load and micro-bending...
Improving the performance of cement-based composites containing superabsorbent polymers by utilization of nano-SiO2 particles
, Article Materials and Design ; Volume 42 , 2012 , Pages 94-101 ; 02641275 (ISSN) ; Fakoorpoor, S. M ; Khaloo, A ; Hosseini, P ; Sharif University of Technology
2012
Abstract
The application of superabsorbent polymer (SAP) as an internal curing agent for cement based composites results in benefits such as reduced autogenous shrinkage and cracking. However, a reduction in compressive and flexural strength usually occurs due to the empty voids remained in the matrix after deswelling of SAP particles. Nanoparticles are good candidates for improving the mechanical performance of cementitious materials, due to their multiple mechanisms of action, not the least their high pozzolanic activity.In the present work, the capability of amorphous nano-SiO2 (NS) as the most widely used nanoparticle in cementitious materials, for retrieving mechanical properties of...
Strength of SCLC recycle springs and fibers concrete subject to high temperatures
, Article Structural Concrete ; 2021 ; 14644177 (ISSN) ; Toufigh, V ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
In this article, the self-compacting lightweight concretes (SCLC) with different fibers were prepared and exposed to elevated temperatures, and their mechanical properties were investigated. Three types of fibers were steel fibers (SF), polypropylene fibers (PPF), and metal springs with a volume fraction of 0.4%. One hundred and fifty cylindrical specimens were prepared, and the compression, tensile and flexural tests were carried out on them after exposure to high temperatures ranging from 25 to 700°C. The findings indicate that incorporation of steel fibers and springs enhanced the compressive strength of concrete by 20% compared to the control specimen. Meanwhile, the polypropylene fibers...
Seismic shear strengthening of R/C beams and columns with expanded steel meshes
, Article Structural Engineering and Mechanics ; Volume 21, Issue 3 , 2005 , Pages 333-350 ; 12254568 (ISSN) ; Kazemi, M. T ; Sharif University of Technology
Techno-Press
2005
Abstract
This paper presents results of an experimental study to evaluate a new retrofit technique for strengthening shear deficient short concrete beams and columns. In this technique a mortar jacket reinforced with expanded steel meshes is used for retrofitting. Twelve short reinforced concrete specimens, including eight retrofitted ones, were tested. Six specimens were tested under a constant compressive axial force of 15% of column axial load capacity based on original concrete gross section, Ag, and the concrete compressive strength, fc′. Main variables were the spacing of ties in original specimens and the volume fraction of expanded metal in jackets. Original specimens failed before reaching...