Search for: shear-strength
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    Investigation of various concrete materials to simulate seismic response of RC structures

    , Article Structures ; Volume 29 , 2021 , Pages 1322-1351 ; 23520124 (ISSN) Asgarpoor, M ; Gharavi, A ; Epackachi, S ; Sharif University of Technology
    Elsevier Ltd  2021
    This paper focuses on the performance evaluation of several concrete models in reinforced concrete (RC) structures subjected to seismic loading. Despite many studies conducted on implementing different characteristics of concrete in constitutive models, there is an essential need for investigating the ability of these models in predicting the behavior of structures in seismic applications. In this paper, several developed plasticity-based constitutive models with the combination of fracture and continuum damage models are investigated for application in seismic loading conditions. Damage-based isotropic and anisotropic models and smeared cracking approach have been applied as complementary... 

    Effects of sulphuric acid pollutant on the shear behaviour and strength of sandy soil and sand mixed with bentonite clay

    , Article International Journal of Geotechnical Engineering ; Volume 11, Issue 2 , 2017 , Pages 114-119 ; 19386362 (ISSN) Hassanlourad, M ; Khatami, M. H ; Ahmadi, M. M ; Sharif University of Technology
    Taylor and Francis Ltd  2017
    Mixture of sandy soil and bentonite clay can be used to seal the sanitary landfills and prevent the spread of leachate. Over time, this mixture may be subjected to different landfill contaminants, including acidic pollutants and shear strength variations. The objective of this research was to study the effects of sulphuric acid pollutant with pH values of 7, 3 and 1 on the shear behaviour and strength of clean sand and sand mixed with bentonite clay using common consolidated undrained triaxial tests. The tests results showed that the presence of acid in the soil pore water changes the shear behaviour pattern of the soil. Acid pollutant decreases the clean sand shear strength. In... 

    A study on the effects bonding temperature and holding time on mechanical and metallurgical properties of al–cu dissimilar joining by DFW

    , Article Transactions of the Indian Institute of Metals ; Volume 70, Issue 1 , 2017 , Pages 125-131 ; 09722815 (ISSN) Safarzadeh, A ; Paidar, M ; Youzbashi zade, H ; Sharif University of Technology
    Springer India  2017
    The aim of this study was to evaluate the influence of bonding temperature and holding time on the metallurgical and mechanical properties for weld joints of 5 mm aluminum to copper using Sn interlayer. The bonding temperature varied from 500 to 600 °C whilst the holding time varied from 30 to 120 min under 8 MPa uniaxial load in 1 × 10−4 torr vacuum. The microstructure analysis, phase analysis and distribution of elements in the interface were performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and element map analysis. It was found that diffusion welding parameters had a significant effect on shear strength. The attained data of tensile strength tests showed... 

    Steel web panel influence on seismic behavior of proposed precast RCS connections

    , Article Structures ; Volume 32 , 2021 , Pages 87-95 ; 23520124 (ISSN) Bakhtiari Doost, R ; Khaloo, A ; Sharif University of Technology
    Elsevier Ltd  2021
    In this study, the experimental finding of two half-scale interior prefabricated Reinforced Concrete column to Steel beam (RCS) sub-assemblage with proposed joint formations with and without web panel in the junction is presented. Previous researches about RCS have been performed to study shear strength of steel web panel in the joint by modeling joint component, however rarely have been conducted to evaluate joint shear resistance experimentally. Over the past 30 years, noticeable analytical and experimental assessments have been performed on the cast in place RCS joints, but seldom have been done on the prefabricated RCS. The steel beams in the proposed joint are attached to the expanded... 

    Triaxial behaviour of a cemented gravely sand, Tehran alluvium

    , Article Geotechnical and Geological Engineering ; Volume 21, Issue 1 , 2003 , Pages 1-28 ; 09603182 (ISSN) Asghari, E ; Toll, D. G ; Haeri, S. M ; Sharif University of Technology
    Cemented coarse-grained alluvium is present in a vast area of Tehran city. Iran including its suburbs. This deposit consists of gravely sand to sandy gravel with some cobbles and is dominantly cemented by carbonaceous materials. In order to understand the mechanical behaviour of this soil, a series of triaxial compression tests were performed on uncemented, artificially cemented and destructured samples. Hydrated lime was used as the cementation agent for sample preparation to model the Tehran deposit. The tests were performed on cemented samples after an appropriate time for curing. The tests on cemented samples show that a shear zone appears as the shear stress approaches the peak shear... 

    Study of Loading Orientation Effect on Shear Strength of Rock Mass Discontinuities with Infilling Based on Laboratory Methods

    , M.Sc. Thesis Sharif University of Technology Malaksiar, Hosein (Author) ; Sadaghiani, Mohammad Hosein (Supervisor)
    Recently, Needs for construction of rock structures and underground ones such as tunnels, dam foundations, power plants and caverns built to keep oil, gas and nuclear waste has increased dramatically. In order to design, construct and excavate these underground structures safely and economically, full understanding of rock mass properties, suitable tools and practical techniques of drilling are necessary. Because of existing this discontinuities, including joints and layered rock masses and their effects on mechanical behavior of rock mass, it is necessary for the geomechanical profile, shear strength and failure mechanism of rock mass to be accurately indentified. Shear strength criterions... 

    Effect of hydraulic hysteresis and degree of saturation of infill materials on the behavior of an infilled rock fracture

    , Article International Journal of Rock Mechanics and Mining Sciences ; Volume 88 , 2016 , Pages 105-114 ; 13651609 (ISSN) Khosravi, A ; Dadashi Serej, A ; Mousavi, S. M ; Haeri, S. M ; Sharif University of Technology
    Elsevier Ltd 

    Prediction of shear strength parameters of hydrocarbon contaminated sand based on machine learning methods

    , Article Georisk ; 2020 Rezaee, M ; Mojtahedi, S. F. F ; Taherabadi, E ; Soleymani, K ; Pejman, M ; Sharif University of Technology
    Taylor and Francis Ltd  2020
    The objective of this paper is to predict the effect of hydrocarbon contamination on the shear strength parameters of sand by using various machine learning platforms. Multilayer perceptron, support vector machine, random forest, gradient boosting method, and multi-output support vector machine were methods used to predict the hydrocarbon contamination impacts on the internal friction angle and cohesion of contaminated sand. Random forest exhibited the best results for cohesion, whereas, for the friction angle, the gradient boosting method outperformed other approaches. Moreover, the multi-output support vector machine yielded better results than those pertaining to a single support vector... 

    Effect of the shear loading direction on shear behavior of rock and finding new empirical method for determining JRC by fractal dimension

    , Article Annual Conference of the Canadian Society for Civil Engineering 2007: Where the Road Ends, Ingenuity Begins, Yellowknife, NT, 6 June 2007 through 9 June 2007 ; Volume 1 , 2007 , Pages 259-267 Khosravi, A ; Sadaghiani, M. H ; Askari, M ; Khosravi, M ; Sharif University of Technology
    Effect of different conditions on shear behaviour of rock has been investigated by various researchers. As known, in larger scale the continuity of the rock material is interrupted by separated planes such as bedding planes, faults, shear zones, closure and the behaviour converts to be inelastic and anisotropic. Generally, discontinuities appear repeatedly in more than one preferential direction, creating a three dimensional structure, reducing its stiffness and shear strength as mechanical effects and increasing its transport velocity associated with discontinuity flow as hydraulic effects. They also make rock behavior more complex and different compared to the behavior of soil. According... 

    A simplified MCFT for shear capacity scaling of R/C beams

    , Article 16th European Conference of Fracture, 3 July 2006 through 7 July 2006 ; 2006 , Pages 1363-1364 ; 9781402049712 (ISBN) Kazemi, M. T ; Broujerdian, V ; Sharif University of Technology
    Kluwer Academic Publishers  2006
    It is well known that shear strength of beams without stirrups shows a strong size effect. At present, several formulas of size effect are used by some codes and suggested by various researchers. Most of those formulas are not in agree with fracture mechanics. Recently, a simple formula based on modified compression field theory, MCFT, was proposed (Collins and Kuchma [1], Lubell et al. [2]), which shows a size effect stronger than the size effect formula based on fracture mechanics, proposed by Bazant (e.g. Bazant and Kazemi [3], Bazant and Yu [4]). In this paper it is shown that with some refined considerations, formulas are resulted in agree with Fracture Mechanics concept. In the derived... 

    Stress-induced anisotropy in random assemblies of oval granules

    , Article 8th International Symposium on Numerical Models in Geomechanics, NUMOG 2002, 10 April 2002 through 12 April 2002 ; 2002 , Pages 61-66 ; 9789058093592 (ISBN) Shodja, H. M ; Nezami, E. G ; Sharif University of Technology
    CRC Press/Balkema  2002
    Stress-induced anisotropy appears during the course of deformation in response to the applied stresses. The distribution of contact normals may be a dominant source of stress-induced anisotropy in granular assemblies. In the present study, stress-induced anisotropy in the fabric of granular materials is investigated through implication of several strain-controlled biaxial compression simulations on random assemblies of oval cross-sectional particles with mixed sizes. Based on a new formulation for distinct element method (DEM), which is referred to as static DEM (SDEM), an efficient computer program is developed to observe the evolution of the fabric in assemblies of oval granules under... 

    Shear repair of reinforced concrete beams using post-tensioning

    , Article 4th International Conference on Repair, Rehabilitation, and Maintenance of Concrete Structures, and Innovations in Design and Construction, 19 September 2000 through 22 September 2000 ; Volume SP-193 , 2000 , Pages 519-549 ; 01932527 (ISSN); 9780870316913 (ISBN) Khaloo, A. R ; American Concrete Institute ; Sharif University of Technology
    American Concrete Institute  2000
    In this paper, shear strengthening of RC beams by confining shear critical region is experimentally and theoretically investigated. Confinement is implemented using vertical post-compression force in the shear critical region with steel plate, bolts and angles. The loading tests include (1) loading beams to first major shear crack, then shear strengthening, and reloading to complete failure, (2) strengthening beams from beginning and loading to complete failure, and (3) loading unrepaired beam to complete failure. lnt1uences of concrete strength, shear span length, longitudinal tensile reinforcement, level of post-tensioning, presence of shear reinforcement, use of continuous plates, and... 

    Shear Capacity of Ultra-High Performance Concrete Rectangular Beams

    , Ph.D. Dissertation Sharif University of Technology Pourbaba, Masoud (Author) ; Joghataie, Abdolreza (Supervisor)
    The application of ultra-high performance concrete (UHPC) as an alternative to conventional/ normal concrete (NC) has grown rapidly in recent years. However, there is limited knowledge on its shear behavior, which is essential for developing design guidelines for structural applications. A detailed parametric study was conducted on 38 beam specimens, half of which were made of UHPC and the other half made of NC. To ensure applicability of findings, two types of UHPC mixes were used, a proprietary and a generic mix. Eighteen of the beams were prepared and tested in Tabriz, Iran, while the other 20 were made and tested in Miami, FL. Test parameters included type of concrete (UHPC and NC),... 

    The seismic performance of new detailing for RCS connections

    , Article Journal of Constructional Steel Research ; Volume 91 , 2013 , Pages 76-88 ; 0143974X (ISSN) Alizadeh, S ; Attari, N. K. A ; Kazemi, M. T ; Sharif University of Technology
    Over the past few decades considerable experimental and numerical studies have been conducted on the Reinforced Concrete columns to Steel beams (RCS) connections. Most of those researches have focused on studying the joint failure modes and ultimate joint strength of specimens utilizing strong beams and columns with weak joints. In this paper, two interior RCS connections were designed based on the Strong Column-Weak Beam (SCWB) criterion. Both specimens were tested under quasi-static reversed cyclic loading. The tested specimens were modeled by a finite element method, which verified with experimental results. Several models with different joint details were investigated using the verified... 

    An investigation on diffusion bonding of aluminum to copper using equal channel angular extrusion process

    , Article Materials Letters ; Volume 65, Issue 12 , June , 2011 , Pages 1862-1864 ; 0167577X (ISSN) Eslami, P ; Taheri, A. K ; Sharif University of Technology
    A new method for production of bimetallic rods, utilizing the equal channel angular extrusion (ECAE) process has been introduced before by previous researchers, but no attempt has been made to assess the effect of different temperatures and holding times in order to achieve a diffusional bond between the mating surfaces. In present research copper sheathed aluminum rods have been ECAEed at room temperature and subsequently held at a constant ECAE pressure, at different temperatures and holding times to produce a diffusional bond between the copper sheath and the aluminum core. The bonding quality of the joints was examined by shear strength test and a sound bonding interface was achieved.... 

    Effect of solidification mechanism on microstructure and mechanical properties of joint in TLP bonded Al2024-T6 alloy

    , Article Science and Technology of Welding and Joining ; Volume 16, Issue 2 , Nov , 2011 , Pages 174-180 ; 13621718 (ISSN) Ghaznavi, M. M ; Ekrami, A ; Kokabi, A. H ; Sharif University of Technology
    Transient liquid phase (TLP) bonding of Al2024-T6 alloy, using gallium (Ga) interlayer, has been investigated. Bonding process was carried out at 470°C for 6 min, and homogenising temperature and time were 495°C and 2 h respectively. Conventional TLP bonding using Ga interlayer was not an appropriate method for joining of Al2024. In this method, the boundary between two Al2024 specimens was not fully eliminated during bonding because of solidification with planar front. In addition, bonding zone was depleted of copper, and as a result, tensile and shear strength of joint decreased to 200 and 110 MPa respectively. TLP bonding under temperature gradient offered very good results in bonding of... 

    A new method for producing bimetallic rods

    , Article Materials Letters ; Volume 61, Issue 19-20 , 2007 , Pages 4110-4113 ; 0167577X (ISSN) Eivani, A. R ; Karimi Taheri, A ; Sharif University of Technology
    In this research, a new method for producing bimetallic rods is introduced. The method is a new application of equal channel angular extrusion (ECAE) process. Advantages of using this method can be expressed as; good dimensional control on both the core and clad layer, possibility of performing the process in more than one pass which can result in larger bonding strength, and the possibility of performing the process in different temperatures which is critical for producing most of the bimetallic joints as well as aluminum-copper joint. The shear strength obtained using this method is compared with the same final product produced by general extrusion process. While the shear strength after... 

    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) Morshedt, R ; Kazemi, M. T ; Sharif University of Technology
    Techno-Press  2005
    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... 

    Room- and high-temperature torsional shear strength of solid oxide fuel/electrolysis cell sealing material

    , Article Ceramics International ; Volume 45, Issue 2 , 2019 , Pages 2219-2225 ; 02728842 (ISSN) Fakouri Hasanabadi, M ; Kokabi, A. H ; Faghihi Sani, M. A ; Groß Barsnick, S. M ; Malzbender, J ; Sharif University of Technology
    Elsevier Ltd  2019
    The structural integrity of the sealant material is critical for the reliability of solid oxide fuel/electrolysis stacks. In the current study, a torsion test is implemented to evaluate and compare its shear strength with a partially crystallized glass sealant at room- and operation relevant high-temperatures. Hourglass-shaped specimens with different configurations of hollow- and full-halves are utilized for testing. The fracture surfaces are visualized via optical microscopy and complementary scanning electron microscopy. In addition, cyclic loading is used to investigate potential subcritical crack growth effects in the sealants. Both, the specimens with a hollow-half as well as the ones... 

    The interface behavior of rock, conventional vibrated and roller compacted concrete

    , Article Geotechnical and Geological Engineering ; Volume 38, Issue 2 , 2020 , Pages 1949-1969 Soltanianfard, M. A ; Toufigh, V ; Ghaemian, M ; Sharif University of Technology
    Springer  2020
    The interface behavior of rock and concrete and between layers of concrete highly affects the performance of concrete dam structures. In this investigation, a modified direct shear test was implemented in the laboratory to evaluate the interface behavior between (1) rock and conventional vibrated concrete (CVC), (2) rock and roller compacted concrete (RCC), (3) CVC and RCC and (4) two layers of RCC. Series of in situ shear tests were also performed between rock and concrete. The friction angle and cohesion for all tested interface were determined and analyzed. The effect of uniaxial compressive strength (UCS) of concrete on the interface behavior was determined. Additionally, the effect of...