Category: Uncategorized

Effect of hybrid micro steel-polypropylene fibers on high strength concrete with micro silica fume

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (90-102)

DOI:10.52113/3/eng/mjet/2014-03-01/90-102

Research Article By:

Othman Hameed Zinkaah

Corresponding author E-mail: al_azawy2001@yahoo.com

ABSTRACT

The present investigations consider the effect of hybrid micro steel- polypropylene fibers on high strength concrete. The fractions of steel and polypropylene fibers are 1% and 0.5% by volume respectively. Many mixes have been investigation by combination between steel fibers and polypropylene fibers with different percentages it is (0%S.F-100%P.P.F), (100%S.F- 0%P.P.F), (25%S.F, 75%P.P.F), (50%S.F-50%P.P.F), (75%S.F-25%P.P.F) in addition to reference mix. Properties of high strength concrete such as compressive strength, splitting strength, flexural strength, static modulus of elasticity, and absorption have been studied. The results showed that, the compressive strength decrease by about 28% when adding (0%S.F-100%P.P.F), and there are a small increasing with adding (100%S.F-0%P.P.F). However the results showed that there are an inverse relationship between compressive strength and the amount of polypropylene fibers. Experimental work also showed that adding (0%S.F-100%P.P.F) decrease the splitting strength by about 16%, while using hybrid fibers increase the splitting strength but less than its increasing when adding (100%S.F-0%P.P.F). It can be concluded that, the maximum effect of hybrid fibers is on the flexural strength, it is reach to 128% more than reference mix. Furthermore absorption increases by using polypropylene fibers.

Keywords: Steel fibers, polypropylene fibers, high strength concrete, compressive strength, splitting strength, flexural strength, modulus of elasticity.

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Analytical modeling of eccentrically loaded RC columns confined with FRP

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (75-89)

DOI:10.52113/3/eng/mjet/2014-03-01/75-89

Research Article By:

Nabil M. A. Hussian and Ali M. Lafta

Corresponding author E-mail: abilali75@yahoo.com

ABSTRACT

This paper presents an analytical research on behavior of columns confined with FRP subjected to axial load and uniaxial bending moment, by using finite element method and ANSYS-14. To indicate the accuracy of this program, five reinforced concrete columns strengthened with carbon fibers from the experimental testing of previous researches are reanalyzed by ANSYS program. The results showed that the percentage of experimental ultimate load to analytical ultimate load are (99.4, 99.6, 99.8, 97.5 and 97.2) %, and there is a reasonable agreement between the load-deflection curves for experimental and analytical results for all studied columns. The effects of important parameters on the ultimate load and the ductility of the column are studied. The results showed that the ultimate load and the ductility are increased by 60.3% and 118.8% as the compressive strength increased from 22 MPa to 40Mpa.The study shows, that the increasing in CFRP layers lead to increasing in the ultimate load and the ductility of the column, The maximum increasing in the ultimate load and ductility for the column are 78% and 69.4% respectively. The results showed that ,the ultimate load and the ductility are increased by 24.1% and 23% respectively when the percentage of steel area is increased from 1% to 4%. Finally, loads with several eccentricities from the center of the column are studied, the results show a significant reduced value in the ultimate load for confined column by 51% at load eccentricity value equal to 125mm. While the column ductility reduced to 42% for the same load eccentricity.

Keywords: Column, CFRP, strengthen, eccentrically load, FEF, ANSYS-14.

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Experimental study for the size effect on the flexural behaviour of SPLWA reinforced concrete slabs strengthened with CFRP strips

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (60-74)

DOI:10.52113/3/eng/mjet/2014-03-01/60-74

Research Article By:

Readh A. Abbas and Ahad Z. Hamoodi

Corresponding author E-mail: readh_56@yahoo.com

ABSTRACT

An experimental Study was conducted to investigate the size effect on the flexural behaviour of sand-porcelinite lightweight aggregate reinforced concrete one way slabs (SPLWAC OWS). In order to get a clear results, eight slabs were casted, and six of them were strengthened with carbon fibre reinforced polymer (CFRP) strips. To investigate the size effect, four slabs were of 300 mm width, 1500 mm length and 80 mm depth and the others were of 300 mm width, 2000 mm length and 108 mm depth. The present study showed that the SPLWAC OWS showed a reverse size effect. The failure mode was by yield of steel for the control un-strengthened slabs, while it was by yield of steel followed by rupture of CFRP strips for the strengthened slabs. Also, the results of this study were compared with those obtained by the ACI equations. This comparison showed that the ultimate moment strength and deflection obtained by the ACI equations were always less than those obtained experimentally.

Keywords: Carbon fiber reinforced polymer strips, sand-porcelinite lightweight aggregate concrete, one way slabs, monotonic loading, variable amplitude loading.

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Experimental and numerical investigation of I-section lightweight concrete deep beams strengthened with CFRP failing in shear

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (46-59)

DOI:10.52113/3/eng/mjet/2014-03-01/46-59

Research Article By:

Riadh A. Abass and Mustafa Sh. Zewair

Corresponding author E-mail: readh_56@yahoo.com

ABSTRACT

The experimental program consisted of testing four I-section reinforced concrete deep beams strengthened with CFRP strips made from lightweight concrete (porcilinate). The experimental program variables include configurations of CFRP. Experimental results obtained from the adopted strengthening CFRP techniques show a significant improvement in the behavior and shear carrying capacity of reinforced concrete deep beams. A stiffer load deflection response is observed for beams strengthened with CFRP strips as compared with response of control deep beam and the inclined CFRP strips give better enhancement than the vertical CFRP strips in ultimate load, deflection and crack width. Nonlinear finite element analysis is performed using the ANSYS-11. The Comparison between experimental results and numerical results indicates that numerical models can successfully used to simulate similar cases. Where the ultimate numerical load to ultimate experimental load ranged between (88%-96%). And good agreement for (load–deflection) curves between numerical and experimental.

Keywords: ANSYS, CFRP, I-section, lightweight, strengthened.

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Effect of magnesium powder addition on some mechanical properties of composite glass-ceramic materials

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (38-45)

DOI:10.52113/3/eng/mjet/2014-03-01/38-45

Research Article By:

Ali Husain Hawi

Corresponding author E-mail: hawy63@yahoo.com

ABSTRACT

Glass – ceramic material as main component in aerospace application (shuttle), bio-material for the veneering of metal restoration in destroy. In this work glass-ceramic from raw material (Oxides + BaO) was prepared. The XRD analysis showed that the heat treatment causes a very rapid crystallization process and at 900 °C, a new phase, MgFe2O4 structure appears in the glass matrix. Addition of different weight percentage of Magnesium metal to glass – ceramic were studied to estimate some properties such as density , young modulus, and hardness. The results show decreasing in density to 2.06*103kg/m3 when add 9%Mg , this result prefer in application of glass-ceramic, especially in aerospace application (window of shuttle). The addition of 9% Mg leads to increase young modulus (E) to (73.5 Gpa). Mg addition on glass -Ceramic leads to decrease Hardness to (260.5 HB at 9% Mg). Microstructure inspection show the gradually spread of Mg metal through the glass matrix leading to a consolidate for all the alternative properties.

Keyword: Addition of Mg, glass ceramic, density, mechanical properties.

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Deriving rainfall intensity-duration-frequency relationships for Kerbala city

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (25-37)

DOI:10.52113/3/eng/mjet/2014-03-01/25-37

Research Article By:

Ayad Kadhum Hussein

Corresponding author E-mail: dr.ayad.alkafajy@gmail.com

ABSTRACT

Intensity-Duration-Frequency (IDF) relationship of rainfall amount is one of the most commonly used tools in water resources engineering for planning designing, and operation of water resources projects. The objective of this research is therefore, to develop operational IDF relationships for the province of Kerbala based on historical data. The IDF curves have been developed considering application to Kerbala area and presented in the form of general mathematical equation, curves relating Intensity–Duration-Frequency of rainfall. The IDF curves are plotted for 2, 5, 10, 25, 50 and 100-year return periods in Kerbala. The values of the constants α, γ and exponents β, τ in the IDF function are calculated from the observed precipitation data by using different methods. Using the methods of goodness of fit has been reached in Kerbala that the Log Pearson type III is the best method of other methods.

Keywords: Plotting position, rainfall frequency analysis.

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The ultimate strength of double short composite columns under concentric loads

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (11-24)

DOI:10.52113/3/eng/mjet/2014-03-01/11-24

Research Article By:

Ragheed Fatehi Makki

Corresponding author E-mail: ragheed.almutwali@uokufa.edu.iq

ABSTRACT

No-Fine concrete filled double steel tube columns (CFDST) are being increasingly used for structural applications. It has been used for submerged tube tunnels, nuclear containment, liquid and gas retaining structures, vessels under external pressure in very deep water and for compression members in offshore construction, this is due to the aesthetic appearance, ease of maintenance and simple of construction. The (CFDST) columns also have excellent resistance to seismic loads and fire. This paper comprises of an experimental study on the structural behavior of double steel tubular columns filled with No-Fine concrete under axial load. Eight samples of double steel circular tubes with different diameters for the inner and outer tubes are used, with different slenderness ratios (L/r), different ultimate strengths of No-Fine concrete (fc′). Also two cases are study for (CFDST) samples first with hollow inner tube and second with completely filled inner and outer tubes with No-Fine concrete.
The experimental results show that the effect of height (the slenderness (L/r) ratio) on the ultimate strength of CFDST columns will have a reverse relation. While the effect of uniaxial compressive strength (fc′) and the effect of fully filling the core of internal tube on the ultimate strength of CFDST columns will have an increase relation.

Keywords: No-fine concrete, compression members, concrete filled double steel tubes (CFDST).

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Statistical analysis of quality parameters of Maamera sewage treatment plant

Muthanna Journal of Engineering and Technology

Volume (3), Issue (1), Year (30 December 2014), Pages (01-10)

DOI:10.52113/3/eng/mjet/2014-03-01/01-10

Research Article By:

Nabaa Shakir Hadi

Corresponding author E-mail: nabaalshimmri@yahoo.com

ABSTRACT

The present study aimed to statistical analysis of quality parameters of Maamera sewage treatment plant at Hilla city. The plant designed to serve 50000 populations and it is operating on biological treatment method (Activated Sludge Process) with an average wastewater inflow of 12000 M3D. Wastewater data were collected yearly by Mayoralty of Hilla from the influent and effluent in Maamera Sewage treatment plant for major water quality parameters, such as biological oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), pH, T, chloride (Cl) over a period of six consecutive years. performance efficiency of the plant has been estimated for each year. A multivariate statistical technique of the data has been attempted by applying Cluster analysis using Statistical Package for Social Sciences (SPSS). The result reveals that the overall performance of the existing was satisfactory. Cluster analysis shows that years ( 2009, 2010 , 2011 and 2012) indicate a good level of treatment compared to that compared to that of 2007 and 2008. Final effluent quality (in term of mean value of six consecutive years) does not meet the stringent regulations proposed by the Iraqi National Standards set by the Regulation 25 of 1967. The BOD5/COD ratio of the influent was calculated as 0.49 in total wastewater.

Keywords: Maamera sewage treatment plant, cluster analysis, statistical analysis.

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Assessment of natural radioactivity levels and radiation hazards for building materials used in some selected provinces in Iraq

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (80-84)

DOI:10.52113/3/eng/mjet/2015-03-02/80-84

Research Article By:

Muhannad Kh. Mohammed

Corresponding author E-mail: muhannad62@yahoo.com

ABSTRACT

The radioactive properties of building materials used for the construction of habitable structures in Iraq were investigated in this study. In the framework of this paper, ten samples of commonly used building materials (bricks and rocks used for incasing) were collected from ten Iraqi provinces for radiometric analysis. The activity concentrations of natural radionuclides in the selected samples were determined by gamma ray spectrometry using sodium iodide (NaI) detector. Based on the results of this study, the use of rocks for incasing manufactured in Al-Rumadi is considered to be unsafe for human habitation from radiological points of view due to relatively high background radioactivity. The radioactivity levels for building materials for the remaining investigated areas were well within the permissible limits.

Keywords: Natural radioactivity levels, radiation hazards, building materials.

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Structural behavior of self compacting concrete

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (69-79)

DOI:10.52113/3/eng/mjet/2015-03-02/69-79

Research Article By:

Jamal Abdul-Samad Khudair and Aqeel Hatem Chkheiwer

Corresponding author E-mail: aqeelcivil@yahoo.com

ABSTRACT

This study investigated the influence of type of concrete (self compacting concrete (SCC) and normal concrete (NC)) and compressive strength (30, 50 and 62 MPa) on the flexural and shear behavior of reinforced concrete beams, as well as punching shear of slabs. To achieve these targets, 18 beams and 6 slabs are equipped, tested and assessed. The tested beams were divided into three groups, the first group consists of six beams failed in flexure, the second group contains six beams without web reinforcement failed in shear with shear span/depth ratios of 3 (slender beams), the third group consists of six beams without web reinforcement failed in shear with shear span/depth ratio of 1 (deep beams), each group consisted of three SCC and three NC geometrically similar rectangular beams of different concrete strengths. Test results indicated that, for beams failing in flexure, SCC beams showed similar ultimate load to NC beams. For slender beams failing in shear, the ultimate load for beams with fc’ of about 32 and 48 MPa, NC beams showed 6.75 % higher ultimate load compared with SCC beams, but beams with fc’ of about 62 MPa, SCC and NC beams showed almost the same ultimate load value. For deep beams, no considerable difference in ultimate loads for SCC and NC beams was noticed. For the six geometrically similar slabs (three slabs made with SCC and three slabs made with NC of different concrete strengths) which were designed to fail in punching shear, it was found that, SCC slabs exhibited 17.25 % higher ultimate punching shear load than NC slabs.

Keywords: Self-compacting concrete, structural behavior, flexure, shear, punching shear.

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Punching shear resistance of lightweight concrete two way slabs strengthened with CFRP strips

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (58-68)

DOI:10.52113/3/eng/mjet/2015-03-02/58-68

Research Article By:

Mazen D.Abdulah

Corresponding author E-mail: mazend_81@yahoo.com

ABSTRACT

The aim of this study is to investigate the experimental behavior of reinforced concrete light weight concrete two-way slabs stiffened by CFRP strips to punching load and compare the results with the finite element model results. The experimental program includes testing a total of 14 slabs (800 x 800 x 70) and (800 x 800 x 90) mm. The slabs are divided into two groups; each group consists of seven slabs. In each group of seven slabs, one slab was left without strengthening as a reference slab, while each slab of the remaining six slabs has a different CFRP distribution. The effect thickness of slabs and shape of the CFRP distribution on the punching shear strength of slabs are studied. All slabs in this study are designed to fail in punching shear. During the test, the slabs are simply supported on all four edges and loaded centrally by a (75 x 75) mm column. Load deflection curves, cracking patterns and effect of variables on the test results are discussed. Experimental results showed that, the CFRP strengthening increased the ultimate punching load of the slabs by (9-26) %, also the first cracking load increased by (38-141) %. The strengthened slabs showed less deflection during loading by about 24% compared to the non- strengthened slabs. Increasing the slab depth gives changes to the slabs punching strength. The slabs are modeled by three dimension finite elements and non-linearly analyzed by the ANSYS program where the concrete is represented by the eight nodes solid element (solid 65) and the CFRP strips are represented by (3D shell 41) with a perfect bond between the CFRP and concrete slabs. Finite elements results showed a comparable results to laboratory tested slabs and the difference is not more 12% in ultimate load.

Keywords: CFRP, solid 65.

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Performance analysis of H-shape multi-band with rectangular patch micro strip antenna

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (50-57)

DOI:10.52113/3/eng/mjet/2015-03-02/50-57

Research Article By:

Ahmed Ghanim Wadday

Corresponding author E-mail: ahmadghw@hotmail.com

ABSTRACT

This paper introduces the design of rectangular multi-band H-shaped microstrip antenna with rectangular slot (RMSA). A special H-structure with constant substrate thickness was simulated for the proposed antenna, and the effects of different stub sizes on rectangular patch antenna performance were investigated. A balanced patch antenna has been designed and analyzed at frequencies of (1 to 6.5 GHz). COMSOL Multiphysics program was used for the simulation. The resonant frequencies and radiation characteristics were analysed. Different frequencies used for Radio Frequency Identification RFID, Worldwide Interoperability for Microwave Access (Wimax) and computer network applications were tackled.

Keywords: COMSOL, muti-band, micro strip antenna, resonant frequency.

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Effect of soil-pile cap interaction on the dynamic response of rotary-machine foundations

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (42-49)

DOI:10.52113/3/eng/mjet/2015-03-02/42-49

Research Article By:

Raid R. Al-Omari, Hussein Mandeel Ashour and Basim Jabbar Abbas

Corresponding author E-mail: tosharaid@yahoo.com

ABSTRACT

This paper investigates the effect of soil-pile cap interaction on the dynamic behavior of the soil-pile system under vibrations. Vertical vibration tests were conducted using experimental models of pile footings embedded in a finite dry sand layer. The pile footings consist of two groups of circular piles with spacing/diameter (S/d) ratio equals to 5; the length/diameter (L/d) ratio for first group was 13.3 and for the second was 20. Each group includes models with different number of piles. A physical model made of steel box of dimensions of 700 × 700 mm and 800 mm in height was used for accommodation the test model. In order to study the effect of cap interaction, the first tests were conducted where a gap was left between the caps and sand surface as reference, and the second tests all caps in contact with sand surface. The maximum displacement amplitudes and the corresponding resonant frequencies of the experimental system were measured using vibration meter and accelometer fixed on the top of the pile cap. The results of both groups indicated that the pile cap interaction significantly increases the vertical amplitudes and increases slightly the resonant frequencies in different proportions.

Keywords: Vertical displacement amplitude, resonant frequency, length of pile/diameter ratio (L/d), spacing of piles/diameter ratio (S/d), pile groups.

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The effect of entrance region geometry on solar chimney power plant performance

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (17-31)

DOI:10.52113/3/eng/mjet/2015-03-02/17-31

Research Article By:

Arkan Kh. Al-Taie and Ali Hayder Mutib

Corresponding author E-mail: arkanaltaie@yahoo.com

ABSTRACT

A numerical simulation to investigate the performance of solar chimney power plant is presented. A small scale model of solar chimney power plant was modelled by using FLUENT software. The solar chimney power plants consist of three essential elements, glass roof collector, chimney (tower) and wind turbine. The output power of the system depends on the input velocity to wind turbine. The turbine inlet velocity is a function of collector – chimney junction type. To solve the governing equations of conservation of mass, momentum, energy. Do-intensity k and Ɛ equations the finite volume method was adopted by FLUENT software to model and analyze such system. The results showed that the geometry of entrance region (collector-chimney junction type) has an effect on the performance parameters especially air flow velocity. Using curved or rounded junction with deflector will improve system mass flow rate by 37.65% as compared with straight junction.

Keywords: Solar chimney, numerical simulation, junction type, performance parameters.

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Characteristics and compositions of solid wastes from Altuhmaziya region in Hilla city

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (10-16)

DOI:10.52113/3/eng/mjet/2015-03-02/10-16

Research Article By:

Nabaa Shakir Hadi

Corresponding author E-mail: nabaalshimmri@yahoo.com

ABSTRACT

The main objective of the present study is to investigate the residential solid wastes characteristics and energy content in Hilla city in the middle of Iraq. The solid waste characteristics, and energy content of Hilla city were found by selecting one area, which represent different lifestyles. Data of samples were collected from 13 multi-storey buildings in the Tuhmaziya region in Hilla city through 2013. The refuse was classified into ten categories (food wastes, paper, plastics , glass, textiles, rubber, tin cans , wood, cardboard, and garden trimmings, etc). The food category was found to be 46.31% of the total weight, and moisture content of 37.52 %. The chemical formula of a residential solid waste of Hilla city was found to be C802.3 H2630.3 O1074.3 N18 with sulfur and without sulfur as C44.6 H146.1 O59.7 N. The energy content (dry basis) was found to be 12369 kJ/kg.

Keywords: Energy content, residential solid wastes, chemical formula, Hilla city.

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Behavior of I-section reinforced concrete deep beams strengthened with CFRP strips subjected to monotonic and cyclic load failing in shear

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (01-09)

DOI:10.52113/3/eng/mjet/2015-03-02/01-09

Research Article By:

Riadh A. Abass and Mustafa Sh. Zewair

Corresponding author E-mail: mm812000@yahoo.com

ABSTRACT

This research is devoted to investigate the effect of CFRP strips on the behavior and load carrying capacity of strengthened I-section reinforced concrete deep beams. The experimental program variables include configurations of CFRP, spacing between CFRP and type of loading (monotonic or cyclic load) on the behavior of strengthened deep beams. The experimental test results confirm that the strengthening technique of CFRP system is applicable and can increase the shear capacity for strengthened of RC beams. In this study, the ultimate load capacity of the strengthened beams ranged between 18% to 38% under monotonic load and between 11% to 26% under cyclic load over the ultimate load capacity of the reference beam. For beams including CFRP changing the spacing of the strips from 50mm to 20mm, increased the strength of the beam by 17%. For beams subjected to cyclic load the mode failure is nearly the same as that of beams subjected to monotonic load and the cyclic loading produced somewhat less brittle behavior in beam under cyclic loading.

Keywords: CFRP, cyclic load, I-section, strengthened.

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Diaphragm Actuator Design with New Rubber Compounds

Muthanna Journal of Engineering and Technology

Volume (4), Issue (1), Year (30 June 2016), Pages (68-74)

DOI:10.52113/3/eng/mjet/2016-04-01/81-87

Research Article By:

Nabel Kadum Abd-Ali

Corresponding author E-mail: nabelkadum@yahoo.com

ABSTRACT

The current work deals with the design of new rubber compounds as a viable alternative for commercial compounds used in diaphragm actuator of brake systems in most commercial vehicles like trucks, tractor-trailers and buses. Two new recipes were proposed to work instead of commercial recipe with experimental and analytical study to prove the high performance properties and workability. The finite element method by ANSYS 13 software was used to study the behavior of these compounds with Mooney-Rivlin 2-parameters during the work pressure range. Most of the results are acceptable competitive.

Keywords: Rubber, diaphragm, brake chamber, stress analysis, Mooney-Rivlin.

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Flexural Behavior of Repaired Reinforced Concrete Slabs with Different Typed of Concrete

Muthanna Journal of Engineering and Technology

Volume (4), Issue (1), Year (30 June 2016), Pages (57-67)

DOI:10.52113/3/eng/mjet/2016-04-01/57-67

Research Article By:

Mazen D.Abdulah

Corresponding author E-mail: mazend081@gmail.com

ABSTRACT

Experimental study of the flexural behavior of repaired reinforced concrete two way slabs with epoxy injection study in this paper. Eleven simply supported reinforced concrete slabs are used, five of which are made with (NSC), four with (HSC) and two with (LWC). The slabs is repair by used epoxy injection method. The aim of repair method is to increase or at last restore flexural strength of these slabs and to monitor their post-repair load-deflection behavior. Investigate the behavior of reinforced concrete two way slabs with different concrete compressive strength before and after repaired with epoxy injection is studied. Also, the efficiency of repaired after loading to the different level between (100%-66%) of the ultimate load obtained for control slab is investigated. The experimental results of repaired two way slabs indicate that; the repair method used is successful to restore or increase the capacity of slabs; the lower-strength slabs is higher increase in capacity compered with other slabs; after retesting the crack repaired do not reopen, instead, new nearby cracks are developed. In repaired slabs the the structural behavior is similar to that of original slabs, however, a lower stiffness and greater ductility are observed.

Keywords: LWC, light weight concrete, NWC, normal strength concrete, HSC, high strength concrete, w/c water to cement ratio.

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Using of Stones in Building the Foundations

Muthanna Journal of Engineering and Technology

Volume (4), Issue (1), Year (30 June 2016), Pages (51-56)

DOI:10.52113/3/eng/mjet/2016-04-01/51-56

Research Article By:

Hussein Yousif Aziz

Corresponding author E-mail: husseinyousif3@hotmail.com

ABSTRACT

The problem of this study is that the building of foundation by stones at the present time leads to develop cracks in the superstructure. Therefore, the solutions and the right manner were suggested for building the stone in the small and big structures. This paper studies using and properties of stones in building of foundations, that the stone is rigid and stiff in the same time very cheap for building, especially in the regions wealthy with stone. The models were taken for analyzing, firstly experimentally in the field site and secondly by Plaxis Program using the Finite Elements with the same properties of the soil and calculate the vertical displacement, vertical strain, factor of safety and bearing capacity. It can be concluded that the using of the reinforced columns in the small foundation in addition to the beam and stones will reduce the vertical displacement and strain to lower values, maintain high value of bearing capacity and increase the factor of safety that makes the structure becomes safer. Also for the big structures like bridges another models were used with higher loadings and the same above parameters were calculated, the stone with special requirements approved to improve and treat the soil parameters even for the big structures.

Keywords: Rock mechanics, foundation engineering, bearing capacity, Plaxis program.

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Effect of change in particle size of the powder coating (Ni- Al) thermally sprayed by flame on the mechanical properties of the coating layer

Muthanna Journal of Engineering and Technology

Volume (4), Issue (1), Year (30 June 2016), Pages (43-50)

DOI:10.52113/3/eng/mjet/2016-04-01/43-50

Research Article By:

عمار رزاق حسن

Corresponding author E-mail: ammarr.alshemary@uokufa.edu.iq

ABSTRACT

In this research was conducted thermal coating process to follow flame spray technology through the use of gaseous mixture consisting of oxygen and acetylene for the purpose of obtaining the surface layer of nickel plating – Aluminum (metco450) on the surface of medium carbon steel type (AISI 1050). Provide an increase in the mechanical properties of the surface of the metal guide and compensate for the missing parts of the surface as a result of the process of wear and tear. Was conducted in three successive phases, first phase involved the preparation of models and to create the basis for this surface models as well as the preparation of powder coating and analyze the chemical components of the models and powder coating. While the second phase involved the implementation of the coating process (nickel – aluminum) using a flame spray coating process was carried out in different ways for each model through a change in the granular size of the powder coating. The third phase of the research included the testing of standard tests check adhesion, examination of roughness, check the wear and tear and check the hardness of the coating as well as microscopic examination of the paint and the surface layer basis. Where results showed that increasing the size particleboard from (25μm) to (75μm) led to increased wear rate and a decrease in adhesion coating layer, as noted increased roughness layer coatings increase size particleboard for powder coating, also led to increase size particleboard for powder coating to a decrease in hardness layer paint.

Keywords: Flame spraying, coating nickel aluminum, medium carbon steel, particle size.

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