SERVICEABILITY BEHAVIOR OF NORMAL AND HIGH-STRENGTH REINFORCED CONCRETE T-BEAMS |
Author : Ibrahim G. SHAABAN1 , Messaoud SAIDANI2*, Muhd Fadhil NURUDDIN3* , Ahmad B. MALKAWI3 , Tarek S. MUSTAFA |
Abstract | Full Text |
Abstract :Serviceability behavior of Normal Strength Concrete (NSC) and High Strength Concrete (HSC) T-beams was experimentally evaluated. The crack pattern was observed, the effect of flange dimensions (breadth and thickness) on the crack pattern and load-deflection response was evaluated experimentally for 10 beams comprising the two studied groups, NSC and HSC T-beams. The short-term deflections were measured experimentally and predicted empirically under mid-span concentrated loading. It was found that increasing the flange width and thickness resulted in higher loads and lower deflections under service loads to a different extent. Prior to failure, the increment in the maximum loads was up to 22% while the deflection reduced by 31% for NSC and 23% for HSC beams. The available equations for determining the effective moment of inertia (Ie) were reviewed and used in predicting the Ie of the cracked beam. The results were compared with the experimental values (Iexp). The Ie showed a noticeable difference, especially for the HSC T-beams. New equations were proposed in which the tensile reinforcement ratio was considered. Compared with the other available equations, the proposed equations demonstrated a better agreement and repeatability of predicting experimental results studied herein. In addition, the proposed equations were used to predict the Ie for experimentally tested T-beams available in the literature. The proposed models showed a high degree of accuracy. |
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STUDY ON CHARACTERISTICS MODIFICATION OF RUL 1 STEEL |
Author : Dragos Cristian ACHITEI1* , Mohd Mustafa Al Bakri ABDULLAH2 , Mirabela Georgiana MINCIUNA1 , Manuela Cristina PERJU1 |
Abstract | Full Text |
Abstract :The paper shows a study about the structural modifications induced on RUL 1 sample, through classic heat treatments. The initial semi-product provides from a laminated bar. It is applied a annealing primary heat treatments, also and quenching and low tempering finally heat treatments. The efficiency of applied thermal processing was evaluated through hardness measurements and micro-structural analyses. |
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THE EFFECT OF FLY ASH/ALKALINE ACTIVATOR RATIO IN CLASS F FLY ASH BASED GEOPOLYMERS |
Author : Dumitru Doru BURDUHOS NERGIS1 , Mohd Mustafa Al Bakri ABDULLAH 2 , Petrica VIZUREANU1 |
Abstract | Full Text |
Abstract :This study focused on the effect of fly ash/alkaline activator ratio and Na2SiO3/NaOH ratio in class F based geopolymers. The objective of this study is to observe the variation of the compressive strength of the final product depending the solid/liquid ratio. In order to form the geopolymer, various parameters were changed during the geopolymerisation process. The fly ash/alkaline activator ratio studied was: 1.5; 2.0; 2.5. The geopolymeric pasta was heated up to 400 °C, 600 °C and 800 °C. After heating the compressive value of geopolymer, with the fly ash and alkaline activator ratio equal to 2 and Na2SiO3/NaOH ratio of 2.5, decreased with approximative 40 MPa comparative with the value of the sample obtained from the same composition dried for 7 days at normal temperature. |
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CORROSION AND WEAR OF WASTEWATER PUMPING SYSTEMS |
Author : Cristian SAVIN1 , Carmen NEJNERU1 , Manuela Cristina PERJU1*, Costica BEJINARIU1 |
Abstract | Full Text |
Abstract :The submersible pumps are submerged in the fluid that must be pumped, this type of pump is capable to push out large volumes of water. The watertight subassembly of this equipment includes a variable power engine that can be used for various household applications or industrial purposes. Wastewater transported by pumps corrodes and wear the transport system. The materials used for the construction of these pumps must withstand the acidity of the water, capitation phenomenon, the wear caused by the particles in the suspension and maintain their operating properties. The paper presents an analysis of the wear and corrosion effects on the wastewater pumps and an analysis of the pump impeller material. |
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INFLUENCE OF NANOSTRUCTURATION ON THE SOUND VELOCITY IN ALUMINUM AL_99.50 |
Author : Alin Marian CAZAC1 , Mihai Adrian BERNEVIG-SAVA1 , Andrei Victor SANDU2 , Costica BEJINARIU1* |
Abstract | Full Text |
Abstract :The paper aims to determine the influence of nanostructure on sound velocity, to severe plastic deformation by cold multiaxial forging of aluminum. The deformation process is discontinuous and comprises deformation processes defining a severe plastic deformation cycle. Thus, a number of 7 determinations were performed for each sample, corresponding to the first 12 cycles of severe plastic deformation. As a result of the analysis of the results, it can be deduced that the area of passages 3, 4 and 5 represents, in fact, precisely the transition zone between micrometric granulation and mesoscopic (ultrafine) granulation, which is only an intermediate area between micrometric granulation and nanometric granulation. |
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ASSESSMENT OF THE TENSION CONDITION THAT OCCURS WHEN THE BODY IS IMMOBILIZED IN A BOSTON-TYPE PLASTIC CORSET |
Author : Constantin NANU1 , Ion POEATA2,3, Cezar POPESCU3 , Lucian EVA3 , Bogdan Florin TOMA3 *, Raluca MUNTEANU3 , Alin Marian CAZAC 4 |
Abstract | Full Text |
Abstract :The paper aims to make a theoretical study - using the finite element method, on the local elastic stresses and deformations that appear in the sagital plane under the use of a Boston corset made of polypropylene.The studies prove the fact that the elastic stress state appearing in the xOy plane in the case of the flexion motion is higher whit 18% than the elastic stress state appearing in the same plane in the case of the extension movement and the higher elastic displacements are recorded in the flexion motion. The occurrence of local deformities at the level of the fractured vertebrae may lead to the wrong splicing of the vertebrae, which causes changes in the geometry of the spine. |
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