Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701BEHAVIOR OF AXIALLY LOADED CIRCULAR R.C. COLUMN CONFINED WITH CFRP WRAPPING SHEET1027104711076310.21608/jesaun.2006.110763ENOmar Ahmed Farghal AhmedCivil Engineering Department, Faculty of Engineering, Assiut University,
Assiut , EGYPTAbd El-Rahman MegahidCivil Engineering Department, Faculty of Engineering, Assiut University, Assiut , EGYPTJournal Article20060510Wrapping of R.C. column by means of Fiber Reinforced Polymer (FRP) reinforcement can significantly improves its structural behavior. The efficiency of this strengthening technique depends mainly upon the encountered parameters related to the original conditions of the element to be strengthened as well as upon both the volume and configuration of the wrapped reinforcement. Such parameters include concrete strength, percentage of longitudinal reinforcement, volume of internal stirrups, shape of cross-section, volume of wrapped reinforcement and arrangements of wrapped sheets. Therefore, an experimental program including seven circular columns is set-up and tested under axial compression load to evaluate the suggested strengthening technique applied to strengthen R.C. columns by means of wrapping Carbon Fiber Reinforced Polymer (CFRP) sheets. The parameters studied through this paper are the arrangements and volume of wrapped CFRP sheets as well as the volume of internal stirrups along these columns. The obtained results are used to evaluate some specific problems in the modeling of CFRP confined concrete, i.e. effective circumferential strain induced in the wrapped CFRP sheets at failure and effect of confining action. Also, the obtained experimental results together with a proposed modified mathematical model are organized in order to investigate the contribution of the externally bonded wrapped CFRP sheets to the load carrying capacity and structural ductility of the strengthened columns. The proposed modified model is based on the expression suggested by the authors to predict the effective circumferential strain induced in the wrapped CFRP sheets at failure. Moreover, an analytical verification of the obtained test results was performed according to the modified proposed model. Both load carrying capacity and structural ductility of R.C. columns improved considerably when applying the proposed strengthening technique. Also, the proposed modified mathematical models suggested to predict the strength of R.C. columns strengthened with wrapped CFRP sheets showed a considerable approach to the results obtained experimentally.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701EFFECT OF POLYPROPYLENE FIBERS ON THE MECHANICAL PROPERTIES OF NORMAL CONCRETE1049105911076510.21608/jesaun.2006.110765ENMohamed R. A. S.Associate Profosser, Civil Engineering Department, Faculty of
Engineering, El-Minia University, El-Minia, Egypt.Journal Article20060510The present work investigates the effect of addition of pure polypropylene fibers to concrete in order to diminish some poor performances particularly in case of ductility and tensile strength. The effect of the addition of polypropylene fibers on the mechanical properties of normal strength concrete is studied. The polypropylene fibers were added at concentration of 0.25, 0.5, 1.0 and 1.5% by volume. Compression, pullout and bending tests were carried out to determine the mechanical properties such as maximum compressive strength, modulus of elasticity, splitting strength, ductility, bond strength, modulus of rupture and the percentage of absorption. On the basis of the experimental results, it can be concluded that, ductility of concrete significantly increased and maximum compressive strength slightly increased with increasing the content of polyproplylene fibers materials. Further increase of polypropylene fibers (higher values than 0.5 vol. %) did not increase the ultimate bond strength, but it provided much more ductile bond behaviour. Besides, the addition of polypropylene fibers caused a significant increase in the percentage of water absorption for the tested concrete specimens.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701COMPRESSIVE STRENGTH AND DURABILITY OF CEMENT CONCRETE CONTAINING ALKALI WASTES OF OIL AND CELLULOSE PAPER INDUSTRIES AND EXPOSED TO AGGRESSIVE ENVIRONMENTAL CONDITIONS1061108511076710.21608/jesaun.2006.110767ENRashwan M. MCivil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptMahmoud H. ACivil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptAly G. A.Civil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptAbo-Elfadel MCivil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptJournal Article20060426Most of R.C. constructions, especially underground, are always subjected to aggressive environmental conditions during their exploatation. These conditions are represented by the aggressive sodium and magnesium sulfate attack from surrounding soil or underground water. When cement-based materials are exposed to sodium sulfate attack, gypsum and ettringite are produced by chemical reactions of sulfate and Ca (OH)2,and C3A. Formation of gypsum plays an important role in the damage of materials. According to that, the actual compressive strength of R.C. elements decreases accompanied with large deformations of concrete. Consequently, a higher reduction of the construction durability occurs. So, the need for using an effective and economic admixtures for the protection of concrete elements against sulfate attack or any other environmental conditions is required. Therefore, the main purpose of this research is to study experimentally the possibility of producing effective and economic admixtures from alkali wastes of oil and cellulose paper industries. Then study their mechanism effect on the compressive strength and durabiliyt of cement concrete specimens, subjected to external sulfate attack and different cycles of durability test. The main variables studied in this research on concrete mixes and hardened specimens were: -three different types of plasticizing organic admixtures(SM-S, CM-B &SM-O), which contain in their compositions an amount of alkali wastes from secondary products of oil and cellulose paper industries, plus a known plasticizing admixture in the Egyptian markets (Addicrete DM2),- three different concentrations of external surrounded sodium and magnesium sulfate solutions and four different numbers of cycles of durability test. The experimental results showed that, The optimum composition of all components of the suggested admixtures (SM-S, CM-B & SM-O) containing alkali wastes from oil and cellulose paper industries and production of them in a liquidity solution was successfully and experimentally achieved. Concrete specimens modified with these admixtures and hardened in 6%Na2SO4+3% MgSO4 until 7 months showed a large increase in their compressive strength by about 46, 37, & 38% and a large increase of their durability index, after 50 cycles, by about 86, 84 & 76%. respectively compared to the control tested specimens without admixtures. Microscopic analysis showed that specimens modified with the suggested organic admixtures have denser and homogeneous structure, their large pores decreased and micro pores increased compared to the control specimens. The vacuums of specimens containing these admixtures after 50 cycles of durability test were filled with prismatic new formations and showed a very small shrinkage cracks between cement paste and filling materials.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701BEHAVIOR OF R.C. COLUMNS CONTAINING ALKALI WASTES OF OIL AND CELLULOSE PAPER INDUSTRIES AND EXPOSED TO SULFATE AND CHLORIDE ATTACK UNDER AXIAL STATIC LOADS1087111111076910.21608/jesaun.2006.110769ENRashwan M. MCivil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptMahmoud H. ACivil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptAly G. ACivil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptAbo Elfadel M. MegahdCivil Engineering Department, Faculty of Engineering, Assiut University, Assiut,
EgyptJournal Article20060401The underground R.C. structures especially footings, piers, piles and column necks are always subjected to aggressive environmental conditions during their exploatation. These conditions are represented by the aggressive sulfate and chloride attack from surrounded soil or underground water. Which implies to deterioration of concrete cover and penetration of sulfate and chloride ions to the interior of concrete elements. According to that, the actual strength of R.C. elements decreases and corrosion damage of embedded steel bars accompanied with large deformations of concrete and steel increases. Consequently, a higher reduction of the construction durability occurs. So, the need for using an effective and economic admixtures for the protection of concrete elements against sulfate and chloride attack is required. Therefore, the main purpose of the project described in this paper is to study experimentally the mechanism effect of the suggested economic admixtures, which fabricated from alkali wastes of oil and cellulose paper industries, on the behavior of normal strength R.C. columns,subjected to external sulfate and chloride attack, under axial static loads. The main variables studied in this research on fifeteen R.C. columns were: three different types of plasticizing organic admixtures(SM-S, CM-B &SM-O), which contain in their compositions amount of alkali wastes from secondary products of oil and cellulose paper industries plus a control plasticizing admixture (Addicrete DM2), and three different concentrations of external surrounded sulfate and chloride solutions (2%Na2SO4+1%CaCL2 -Group A, 4% Na2SO4+2%CaCL2 - Group B, and 6% Na2SO4+3% CaCL2 - Group C). The experimental results showed that, Ultimate loads, stiffness, deformations, mode of failure and properties of the failure zone of the different groups of R.C. tested columns are significantly affected by the suggested admixtures and the concentration of sodium sulfate and calcium chloride solutions. R.C. columns modified with these admixtures(SM-S, CM-B &SM-O) and hardened in 6% Na2SO4+3% CaCL2 until 7 months showed a higher increment in their ultimate and working loads by about 51, 41, & 15% , a large increase of their energy absorption and ductility index of about 90, 47 & 33% over than that of the control column and a decrease of their ultimate longitudinal concrete strain by about 40, 24 & 18%, respectively compared to the control tested column without admixturesAssiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701SHEAR RESPONSE OF LARGE R. C. BEAMS PROVIDED WITH SIDE BARS UNDER REPEATED LOADING1113113111077010.21608/jesaun.2006.110770ENYehia. A. HassaneanCivil Department, Faculty of Engineering, Assiut University, Egypt.Journal Article20060601Cracks of reinforced concrete beams may be expected under a certain service load because of low tensile strength of concrete. In other hand, cracking of reinforced concrete structures is considered undesirable, not only aesthetic reasons, but also because it adversely affects durability and leads to corrosion of embedded reinforcement. So distribution of longitudinal reinforcement is required along the side faces of large concrete beams to control cracking. Most of national codes recommended provision of large beams with side bars added at both sides of the beam cross-sections. Some of these bars may lie at compression or tension zones according to their arrangement. These bars contribute to the overall shear strength and useful in the design of the reinforced concrete cross-sections. The aim of this work is to study the response of short beams as affected by side bars location, amount of area and arrangement along the side face of the beams and subjected to repeated loading. For this purpose an experimental program was set up and tests on ten large reinforced concrete short beams were carried out under transverse service repeated loading followed by static loading up to failure. The patterns of cracks were traced, the modes of failure were observed, the crack widths were measured, and the deformations were recorded as well as both cracking and ultimate loads were also measured. The results show that providing side bars to short beams have a significant and considerable effect on shear response of such beams and hence it should be recommended to be taken into account in designing of such beams.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701PREDICTION OF FUTURE EXPECTED DAMAGE OF UNDERGROUND R.C. ELEMENTS EXPOSED TO INDUCED SEWAGE WATER THROUGH UNCONFINED POROUS MEDIA1133115711077210.21608/jesaun.2006.110772ENRashwan M. M.Associate professor, Civil Engineering Department, Assiut University, Assiut,
Egypt.Journal Article20060515Sulfate and chloride attack for underground R.C. constructions is an important subject of many researchers. Chemical attack by aggressive waters specially sewage is one of the factors causing deterioration and corrosion damage of concrete in the underground R.C. elements . The chemical resistance of R.C. elements against chloride and sulfate attack induced by sewage water is expressed by the percentage of their mechanical property losses. Sulfate attack of concrete building foundations induced by sewage water was studied in the field. Effect of the diffused salts concentration by sewage waters from multiple seepage pits through a confined porous media on the load carrying capacity of underground R.C. columns was analytically studied. But, the influence of chloride and sodium sulfate solutions diffused by sewage water through unconfined porous media on the expected deterioration and corrosion damage of underground R.C. elements after a long period of time, specially footings and necks of columns, has not been enough studied . So, in this paper is developed an analytic model for the effect of the induced chloride and sodium sulfate salts by sewage water through unconfined porous media on the future corrosion damage and deterioration of concrete in underground R.C. elements specially columns. The finite difference technique is used and a computer program is developed and written in a basic language to compute the future mechanical properties losses of R.C. elements exposed to sewage water for a long period of time. Analysis of the numerical results shows that, the expected deterioration and corrosion damage of any underground R.C. elements exposed to sodium sulfate and chloride solutions flow induced by sewage water depend mainly on the time of exposure to these salts, radial distance of the concrete structure from the sewage resources and their number, height of the sewage water solution and its relative concentration at that structure. The difference between the values of of “CFc” and “Єcf “ for unconfined and confined porous media decreases gradually and slowly with increasing time until reaching equal value ( CFc = 0.696, Єcf =5.48x10-4) after 8 years. The unconfined porous media properties (k,ф) and total relative concentration "Ca/Co" of diffused chloride and sulfate salts at that structure have not any effect on its mechanical properties losses .Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701ESTIMATION OF THE MINIMUM FLOOR LENGTH BEHIND SLUICE GATES AGAINST SCOUR UTILIZING SOLID BED AND ERODIBLE BASIN1159117411077510.21608/jesaun.2006.110775ENGamal Abouzeid Abdel-RahimAssociate Prof., Civil Engineering Department, Assiut University, Assiut,
71516, Egypt.Journal Article20060511Presented in this paper are the findings of experimental investigations carried out for the determination of scour reach behind three vents regulator due to a drowned and free hydraulic jumps over a partially rigid apron extended to an erodible sand basin. The study is performed in two categories; the first is to find out the sum of the lengths of rigid apron behind the gates in addition to the length of scour hole formed downstream, while the second is to find the minimum length of rigid apron behind the gates to prevent erosion downstream it. Both categories are carried out under the conditions of symmetrical and asymmetrical under-gated regulations. A trapezoidal channel with 1:1 side slopes and 0.0001 longitudinal bed slope was used. A model of regulator with three vents and two piers was selected to study the influence of some relevant parameters on the scour reach of rigid apron behind sluice gates. The test parameters were the head difference between the upstream and downstream water levels relevant to the uniform water depth (ranges from 0.004 to 1.2), the flow rate and the gate opening height. The mean diameter of the soil particles in the sand basin was kept constant at 0.502 mm. From the comparison between the results of both the studied categories, it is found that the minimum length of rigid apron to prevent scour (Ls) is greater than the sum of the lengths of rigid apron and that of scour hole formed behind it (L+Xs ). Analysis of the results revealed the dependence of the evaluated minimum scour length on the studied parameters. Some empirical relations in dimensionless forms concerning the scour reach against some reliable parameters were obtained and compared favorably with other relations and the existing ones in the field.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701ASSESSMENT OF RIVERBANK FILTRATION FOR POTABLE WATER SUPPLY IN UPPER EGYPT1175118411077910.21608/jesaun.2006.110779ENMohamed ShamrukhAssociate Professor, Department of Civil Engineering, Faculty of
Engineering, Minia University, Minia, Egypt.Journal Article20060311Riverbank filtration (RBF) is a process in which river water is induced to flow through riverbed soils to pumping wells located on the banks. During this passage through the riverbed and aquifer, dissolved and suspended contaminants as well as pathogens are removed. In Upper Egypt, there is interesting in implementation of RBF because it has the potential to replace the current bad quality groundwater wells. In this study, a pilot studied site consisting of three handpumps installed about 8 m from a main canal was monitored. These handpumps are used to supply potable water for private houses, Qena Governorate, Upper Egypt. Water samples from these handpumps, main canal, and municipal groundwater wells were examined. Quality measurements were carried out. The results of these bank handpumps were compared with those of canal and municipal groundwater wells. Phiso-chemical quality of handpumps water is acceptable for drinking. There is a caution about the microbial quality of produced water. The cost of applying RBF technique is less than traditional surface water or groundwater treatment plant. Results of this pilot-scale site showed the effectiveness of RBF as a suitable method in Upper Egypt with low cost.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701THE RATIONAL USE OF FINITE ELEMENT METHOD IN THE ANALYSIS OF FLEXIBLE PAVEMENTS1185121111078010.21608/jesaun.2006.110780ENAbd Alla E. M.Civil Engineering Department, Faculty of Engineering, Assiut University,
Assiut, Egypt.Journal Article20060527The environment, traffic loading, material properties and construction practices are main factors influencing pavement performance. Traffic loading with different wheel configurations is simultaneously moving on highways. Moreover, the pavement boundary conditions affect pavement behaviour. To predict pavement responses and performance, traffic loads with different characteristics are considered to estimate stresses and deformations through pavement. These responses in case of layered pavement system are less than those obtained for the ideal homogeneous case depending upon the stiffness of the layers. Semi-analytical solutions are available to analyze the behaviour of elastic layered pavement subjected to traffic loads. For more complex cases of layered pavement or loading conditions, it is necessary to perform numerical analysis using finite element technique. In addition, most of pavement materials do not linearly perform under the action of traffic loading. Therefore, linear and non linear analyses were preformed for first series of the investigation, which take in account the effect of tyre pressure, axle load, asphalt layers rigidity and pavement layers properties. Also, the influence of state of loading, tyre type and some boundary conditions on pavement responses is considered in the second series. Furthermore, for moving traffic loads, the effects of viscous damping, and load frequency on the deflection and stress have been investigated. In this paper, the ANSYS programs version-8 and version-10 are used to analyze in three dimensions the behaviour of layered pavement systems under static and moving vertical loads and to obtain stresses and deflections through it considering the realistic properties of the pavement layers indicating load transmission issues for a wide variety of materials stiffness. In this research, the pavement is modeled as a multilayered elastic system composed of a subgrade assumed to be an infinite medium upon which layers of finite thickness infinitely extended horizontally are laid. Discussing and analyzing of obtained results are presented and the main conclusions are drawn out.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701THE EFFECT OF RADIATION AND BUOYANCY ON BOUNDARY LAYERS INDUCED BY CONTINUOUS SURFACES STRETCHED WITH RAPIDLY DECREASING VELOCITIES1213122411078710.21608/jesaun.2006.110787ENA. A. MohammadeinDepartment of Mathematics, Faculty of Science, South Valley University,
Aswan, Egypt.W. A. AissaMechanical Power Department, High Institute of Energy, South Valley
University, Aswan, Egypt.Journal Article20060314The present study is devoted to study the influence of radiation and buoyancy on heat and mass transfer characteristics of the selfsimilar boundary layer flows induced by continuous surfaces having a prescribed variable surface temperature and stretched with rapidly decreasing power law velocities. The effects of mixed convection flow with suction in the presence of a quiescent fluid medium of constant temperature are considered. Rosseland approximation is used to describe the radiative heat flux in the energy equation. The transformed governing equations are solved numerically and the velocity and temperature profiles as well as the local Nusselt number and skin friction coefficient are presented. Results show that the effect of radiation is to keep the molten mass away from the slot warmer, reduces the friction factor and increases the heat transfer rate compared to the case in the absence of radiation.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701SLIDING MODE CONTROL OF LINEAR SYNCHRONOUS MOTOR SERVODRIVE1255126411078110.21608/jesaun.2006.110781ENAbdel-Magid M. A. MohamedElectrical Engineering Department, Aswan Faculty of Engineering,
South Valley University, Aswan, EgyptJournal Article20060412This paper proposes a method to design sliding mode control (SMC) for the position tracking control of a permanent magnet linear synchronous motor (PMLSM). The controller is designed to achieve accurate performance in the presence of unknown disturbance and parameter uncertainties. The components of the control law, the equivalent component and the robust component, are designed such that the nominal system exhibits desirable dynamics and the reaching condition is guaranteed. Switching surface is designed based on pole placement and generalized matrix inverse. Simulation results show that the suggested procedure provides high performance dynamic characteristics and robust with regard to external disturbance and parameter variations.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701INFORMATION HIDING IN VIDEO1265128211078310.21608/jesaun.2006.110783ENYousef B. MahdyComputer Science Department, Faculty of Computer and Information,
Assiut University, Egypt.Mohammed A. AtieaComputer Science Department, Faculty of Computer and Information,
Assiut University, Egypt.Journal Article20060328This paper proposes a video information-embedding scheme in which the embedded information is reconstructed without knowing the original host video. The proposed method presents high rate of information embedding and is robust to motion compensated coding, such as MPEG-II and MPEG-III. The characteristic of the proposed scheme is to use pixels contractive relation to assist motion compensated coding process. Information is embedded in video frames using the block DCT. Embedded frames are then coded using MPEG-III. After that the information will be extracted from video with high efficiency. Experimental results have indicated that the method is robust against MPEG encoding and re-encoding.Assiut University, Faculty of EngineeringJES. Journal of Engineering Sciences1687-053034No 420060701HIGH-SPEED, AREA-EFFICIENT FPGA-BASED FLOATING-POINT ARITHMETIC MODULES1283129211078410.21608/jesaun.2006.110784ENM. TaherElectronic Engineer in Tibben Institute for Metallurgical StudiesM. AboulwafaFaculty of Engineering, Helwan University, Cairo, EgyptA. AbdelwahabFaculty of Engineering, Helwan University, Cairo, EgyptE. M. SaadFaculty of Engineering, Helwan University, Cairo, EgyptJournal Article20060408In this paper, single-precision floating-point IEEE-754 standard Adder/Subtractor and Multiplier modules with high speed and area efficient are presented. These modules are designed, simulated, synthesized, optimized, and implemented on an FPGA based system. A comparison between the results of the proposed design and a previously reported one is provided. The effect of normalization unit at the singleprecision floating-point multiplier and adder/Subtractor modules on the area, and speed is explained.