Publication List for University of Tripoli

Publication statistics for University of Tripoli

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  • 86

    Conference paper

  • 250

    Journal Article

  • 15

    Book

  • 7

    Chapter

  • 2

    PhD Thesis

  • 2

    Master Thesis

  • 0

    Final Year Project

  • 12

    Technical Report

  • 1

    Unpublished work

  • 0

    Document

BEHAVIOR OF REINFORCED CONCRETE BEAMS CONTAINING LIGHTWEIGHT AGGREGATE IN THE TENSILE ZONE

In reinforced concrete design, the concrete in the tensile zone is assumed to be ineffective and increase the dead load of the structural elements. In order to reduce the self-weight, this paper examines the structural behavior of reinforced concrete beams containing lightweight concrete in the tensile region and normal weight concrete in the rest of the beam. The lightweight concrete was made from waste polystyrene. Four reinforced concrete beams were prepared with different depth of lightweight concrete. The control beam B1 consists of normal concrete. In Beams B2, B3 and B4, the depth of lightweight concrete was 25%, 50% and 75% of the total depth of the beam measured from the bottom surface respectively. A four-point bending test was conducted on all beams. The beams were loaded in increments until failure. At each load increment, the central deflection was determined. Cracks initiation and the mode of failure were observed during the experiment. The failure load was found to decreases with the increase of depth of lightweight concrete. The presence of lightweight aggregate tends to cause brittle failure. In addition, the mode of failure for reinforced concrete beams containing lightweight concrete was a shear failure. arabic 11 English 79
Hakim S. Abdelgader(6-2020)
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Structural Assessment of Reinforced Concrete Beams Incorporating Waste Plastic Straws

The behavior of reinforced concrete beams containing fibers made of waste plastic straws (WPSs) under the three point bending test is examined. The e ect of WPS fiber addition on the compressive and split tensile strength is reported. Four concrete mixes were prepared. The control mix PS-0 had a proportion of 1 cement: 1 sand: 2 coarse aggregate and a water cement ratio of 0.4. In the other three mixes PS-0.5, PS-1.5 and PS-3, 0%, 0.5%, 1.5% and 3% of WPS fiber (by volume) was added respectively. The results show that at 0.5% WPS, there is slight increase in compressive strength. However, beyond 0.5% addition, a decrease in compressive strength is observed. The split tensile strength shows a systematic increase with the addition of WPS fibers. The reinforced concrete beams containing WPS fibers show higher ductility as demonstrated by the larger ultimate tensile strain and ductility index (Du/Dy). There is a tendency to have more fine cracks with the presence of WPS fibers. arabic 9 English 76
Hakim S. Abdelgader(10-2020)
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Impact response of novel layered two stage fibrous composite slabs with different support type

The performance of novel Layered Two Stage Fibrous Composite slabs (LTSFC) was pioneered under falling mass collisions using a combined experimental and numerical study. Such LTSFC slabs consist of three layers with and without the insertion of glass fibre mesh between the layers. LTSFC techniques were used to fabricate the composite slabs with three layers including 3%, 1.5%, and 3% of fibre content for the top, middle, and bottom layers respectively. Sixteen MLPAFC square slabs were cast with only short hooked end fibres and tested under falling mass collisions by amending two parameters namely the type of support (fixed and hinge) and support layout. Two distinct support layouts on two types of support were considered and tested with and without the glass fibre mesh between layers of LTSFC. A glass fibre mesh was introduced between the three layers to block crack growth propagation and absorb additional collision energy. The glass fibre mesh insertion between the layers and the LTSFC production technique were considered as novel modifications. A numerical study using Auto desk Fusion 360 was conducted and compared with experimental results. The numerical results showed fair agreement with the experimental test results. Based on the validated numerical models, collision energy and cracking pattern evolution were studied. The findings indicated that the glass fibre mesh insertion between the layers combined with steel fibres disrupted crack proliferation, thus exhibiting superior engrossed collision energy and postponing crack growth. Additionally, the engrossed collision energy at crack initiation and ultimate crack for the slabs with four sides fixed and hinged support were greater with respect to two opposite sides fixed and hinged support. Numerical values were in reasonable agreement with the experimental values in terms of collision energy and cracking patterns. arabic 13 English 81
Hakim S. Abdelgader(2-2021)
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Impact performance of novel multi-layered prepacked aggregate fibrous composites under compression and bending

Multi-layered Prepacked aggregate fibrous composite (MLPAFC) is a new type of concrete, which is prepared in two subsequent stages of aggregate-fibre skeleton prepacking and cementitious grouting. In this study, ten MLPAFC mixtures were prepared in three subsequent layers incorporating different contents of four different types of steel fibres. Long and short hooked-end and crimped steel fibers were adopted with 3.0 and 1.5% dosages for the outer and interior layers, respectively. In-between the three MLPAFC layers, two layers of Glass Fiber Mesh (GFM) were inserted in five of the ten mixtures. The impact response of the MLPAFC mixtures was evaluated using two test methods. In the first, the ACI 544-2R repeated free-falling weight test was followed using disk specimens, while flexural free-falling weight on prism specimens was the second adopted impact test. Moreover, Weibull distribution was used to statistically analyse the discrepancies of the obtained experimental impact records. The impact tests results revealed that MLPAFC can absorb significantly high energy under falling weight impact due to its structure and the dual crack arresting activity of both steel fibers and GFM. The cracking number of impacts of MLPAFC cylindrical specimens without GFM was increased by approximately 530–870% compared reference specimens, while increment percentages reaching 1350% were recorded at failure stage. The impact resistance of MLPAFC prisms under flexural impact was noticeably improved, yet with lower percentages than cylindrical specimens. The insertion of intermediate GFMs let to additional developments in the impact strength of both cylindrical and prism specimens. arabic 14 English 97
Hakim S. Abdelgader (12-2020)
publisher's website

دراسة مدى ملائمة المياه الجوفية بمدينة مزدة للأغراض المنزلية

مدينة مزدة هي أحد اكبر المدن الليبية في الجبل الغربي من حيث الكثافة السكانية , تقع مدينة مزدة في منتصف الشمال الغربي من ليبيا بين خطي عرض 13.4 شمالا و 28.17 جنوبا وخطي طول 14.10 شرقا و11.40 غربا وتقع جنوب مدينة طرابلس( بحوالي 200 كم) . تعتبر المياه الجوفية هي المصدر الرئيسي للمياه في هذه المنطقة والتي يعتمد عليها السكان في تلبية جميع احتياجاتهم من شرب ، زراعة ، صناعة , بالإضافة إلى الاستخدامات الأخرى. ويوجد بها العديد من الآبار والتي يتراوح عمقها من 500 متر إلى 750 متر. في هذه الدراسة تم اختيار عدد 4 آبار منتشرة بالمنطقة لغرض تصنيف نوعية المياه وتقييم استخدامها للأغراض المختلفة. تم قياس درجة الحموضة لعينات المياه في آبار قيد الدراسة ، بالإضافة إلى تقدير العناصرالثقيلة الرئيسية في المختبر كما تم تقدير العسرة الكلية للمياه والأملاح الذائبة الكلية.كما تم اجراء الفحص الميكروبي للكشف عن إمكانية وجود البكتريا من عدمه. بينت نتائج الاختبارات المعملية للمياه الجوفية للمنطقة بأن مياهها تعتبر متدنية النوعية وغير صالحة للشرب وذلك استنادا إلى مواصفات مياه الشرب في ليبيا لسنة (2008)الصادرةعن المركز الوطني للمواصفات والمعايير القياسية , معاييرمنظمة الصحة العالمية ((WHO لسنة (2011)، منظمة والأغذية الزراعة ( FAO), وأيضا وكالة حماية البيئة الأمريكية EPA) ). arabic 112 English 0
عزالدين محمد ابراهيم(8-2020)
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دراسة تراكم بعض العناصر الثقيلة في نسج أربعة أنواع من الأسماك المجمعة من شواطئ طرابلس ومصراته/ليبيا

تضمنت الدراسة تقدير تركيز بعض العناصر الثقيلة (الرصاص Pb , النحاس uC , الكادميوم dC) في عضلات أربعة أنواع من الأسماك المجمعة من الساحل الليبي قبالة شواطئ طرابلس ومصراته وقسمت الأسماك المصطادة إلى ثلاث أطوال وأوزان مختلفة (كبير,متوسط,صغير). أجريت هذه الدراسة في فصل صيف 2019 , وأوضحت نتائج الدراسة أن تراكم العناصرالثقيلة كان في عضلات أسماك البوري أكثر من أنواع الأسماك الأخرى وكان للطول والوزن علاقة طردية في زيادة تركيز العناصر الثقيلة في عضلات هذه الأسماك إذ كانت تزداد بزيادة الطول والوزن وفي جميع الأنواع الأربعة المدروسة. وتشير النتائج إلى أن: تركيز الرصاص في عضلات أسماك ( التريليا,المرجان,الشكورفو)كانت ضمن الحدود المسموح بها حسب منظمة الصحة العالمية وحسب FAO أما عضلات أسماك البوري فقد كان تركيز الرصاص فيها أعلى من الحدود المسموح بها حسب WHO وحسب FAO. كما لوحظ أن تركيز الكادميوم في كل العينات كان ضمن الحدود المسموح بها حسب WHOوحسب FAO. أما تركيز النحاس في عضلات أسماك( البوري , الشكورفو) فقد كان أعلى من الحدود المسموح بها حسب(WHO,FAO ) أما (التريليا ,المرجان) فقد كانت ضمن الحدود المسموح بها حسب (WHO,FAO). arabic 183 English 0
عزالدين محمد ابراهيم, خديجة محمد السموعي(12-2020)
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Optimizing thermal insulation of external building walls in different climate zones in Libya

An efficient way to reduce the energy required for conditioning buildings and therefore to reduce CO2 emission is the use of proper thermal insulation in buildings' external walls. This measure requires data from metrological stations that can be used in the optimization of the thermal insulation. The main objectives of this study are to construct thermal climatic zones for Libya and to specify the optimum insulation thickness for external walls for the different zones. This work is comprehensive as the metrological data from all existing 33 weather stations has been collected and used for identifying thermal zones. For the optimization of the construction of external walls, the most commonly used local wall structures are investigated: hollow concrete block, limestone block and hollow brick. In addition, four thermal insulation materials: extruded polystyrene, expanded polystyrene, rock wool and foamed polyurethane are used with every wall type. Optimum insulation thickness, energy savings, energy cost and payback periods were estimated for the 33 locations using life cycle cost analysis. A map is constructed for the thermal zones based on degree-day values for the entire country. The results show that limestone blocks with expanded polystyrene insulation form the optimum wall construction as it provides the minimum total cost for all locations. Depending on the Degree-day values, the optimum insulation thickness varies between 5.4 and 15.3 cm across the country with energy saving varies between 28 and 178 $/m2. Using the optimum thickness, the average CO2 emissions can potentially be reduced by about 85%. Finally, a contour map represents the optimum thickness of expanded polystyrene is presented in this work. arabic 12 English 80
Samah Khlifa Otman Alghoul, (1-2021)

Investigating Language Tests’ Content Validity in Public Schools in Tripoli

Investigating Language Tests’ Content Validity in Public Schools in Tripoli arabic 12 English 65
Yousra Ali Moftah Alghanemi, Fuzia Moh A Elwafi, (1-2020)