Muthanna Journal of Engineering and Technology(MJET)

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.

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.

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.

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.

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.

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.

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.

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.