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Article
BEHAVIOR OF SCC BEAMS STRENGTHENED WITH CFRP UNDER SHEAR

Authors: Sarmad S. Abdulqader --- Ragheed F. Makki --- Mohanad W. Mousa
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2019 Volume: 10 Issue: 1 Pages: 111-126
Publisher: University of Kufa جامعة الكوفة

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Abstract

This paper presents an experimental study of structural behavior of self compacting reinforced concrete beams strengthened in shear by vertical CFRP strips. The experimental work consists of casting and testing of eleven simply supported reinforced concrete beams. One of the tested beam was un-strengthened to be considered as beams, while the remaining beams were tested after being strengthened using vertical CFRP strips. In this study, three parameters were considered, the configuration of CFRP sheets wrapping system, i.e. two sides, U-shape and full wrapped, effect of horizontal strap of CFRP strips to enhance the vertical CFRP strips and CFRP amount. The results showed that the presence of horizontal strap of CFRP strips on the vertical strips increases the shear capacity of the beams ranged between (3-27)% for beams with the same properties, while the increase in the ultimate loads ranged between (20-26)% and (39.5-46)% by comparison of wrapping system (two side with U-shape) and (two side with full wrapped) of CFRP strips, respectively.


Article
SUGGESTED EQUATIONS FOR MECHANICAL PROPERTIES OF SELF COMPACTING CONCRETE STRENGTHENED WITH STEEL FIBERS AND EFFECT OF SUCH FIBERS ON SHEAR CAPACITY OF SIMPLY SUPPORTED DEEP BEAMS UNDER AXIAL LOADS

Authors: Wissam Khadum Al-Saraj --- Sarra’a Dhiyaa Jaafer
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 4 Pages: 119-131
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Deep beams are structural elements that commonly design for bridges, girders, foundation walls, pile caps and others. Also, using Self Compacting Concrete (SCC) mix for deep beam is a suitable choice for deep beams because of reinforcement congestion therein. The main objective of this work is to study the shear capacity of SCC reinforced concrete deep beams subjected to axial load, so that both of experimental and analytical works are done. The experimental work consists four simply supported deep beams casted by using SCC mix with steel fibers and tested. All these beams have dimensions 1300mm length, 350mm high, 150mm width and have been subjected to axial force with (100) kN value and then subjected to two-point loads. The variables of this work are vertical and horizontal shear reinforcement and steel fibers ratio in order to study their effects on first crack load and ultimate load and mid span deflection. From the experimental results obtained all the tested beams failed by diagonal splitting mode with some crushing at support zones (in some beams). The second part is the analytical study of this research, including presents proposed equations to estimate the mechanical properties as: compressive strength f`cf, splitting tensile strength ftf, modulus of rapture frf, and modulus of elasticity Ecf of fibrous SCC.


Article
MECHANICAL PROPERTIES OF MRP LIGHTWEIGHT CONCRETE AND EFFECT OF COMPRESSIVE STRENGTH ON SHEAR CAPACITY OF BEAMS

Authors: Wissam Kadhim AlsaraJ --- Layth Abedalbari Aljaberi --- Hayam Yousuf Alhamdani
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 4 Pages: 145-154
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The objective of this study is to investigate the effect of compressive strength on the shear capacity of Modified Reactive Powder Lightweight Concrete (MRPLWC) Beams. The structural behavior of (3) MRPLWC beams without web reinforcement under two point loading system , are studied. Three percentage of Silica Fume (SF) were used to improve the compressive strength of MRPLWC. The experimental results pointed that a positive correlation between the compressive strength and diagonal cracking load and ultimate shear load. Increasing the compressive strength from (89.53 MPa) to (90.3) MPa lead to increase the diagonal cracking load Vcr and increasing ultimate shear load Vu .


Article
Effect of Different Friction Stir Spot Welding Techniques on the Mechanical Properties and Microstructure of Aluminum AA2024-T3
تأثير استخدام تقنيات لحام الاحتكاك الخلطي النقطي المختلفة على الخواص الميكانيكية والبنى المجهرية لسبيكة الألمنيوم AA2024-T3

Authors: Akeel Z. Mahdi عقيل زكي مهدي --- Samir A. Amin سمير علي أمين --- Sadeq H. Bakhy صادق حسين باخي
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2019 Volume: 22 Issue: 2 Pages: 117-123
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

This paper presents a comparison of using different techniques for stir spot welding of Aluminum 2024-T3, which are refill friction stir spot welding (RFSSW), edited (RFSSW-pin) and conventional friction stir spot welding (FSSW), depending on the obtained tensile shear strength property. Specimens were prepared from AA2024-T3 sheet for chemical analysis and mechanical tests. Workpieces were stir spot welded utilizing the above mentioned techniques at four rotational speeds (2000, 2500, 3000 and 4000 rpm) using tool pin diameters (5 and 7 mm) for conducting the tensile shear tests. The microhardness along the cross section of the welded specimens was conducted at the best conditions as well as the microstructure examination. The comparison results revealed that at the rotational speeds (2000 and 4000 rpm) in both cases of tool pin (5 and 7 mm), the ultimate tensile shear force was slightly higher than that for other speeds. However, the ultimate tensile shear force was found higher at 3000 rpm speed with a tool pin 7 mm. The microhardness results manifested a W-shape at the best conditions. Finally, the microstructure examination depicted the morphology of the main zones of the weld joint.

يقدم هذا البحث مقارنة بين استخدام تقنيات مختلفة للحام الاحتكاك الخلطي النقطي لسبيكة الألمنيوم 2024-T3 ،التي تشمل لحام الاحتكاك الخلطي النقطي المعاد الملء (RFSSW) ، لحام الاحتكاك الخلطي النقطي مع المعاد الملء المعدل (RFSSW-pin) و لحام الاحتكاك الخلطي النقطي التقليدي (FSSW) اعتماداً على قوى القص الناتجة من اختبار الشد. تم تحضير العينات من صفيحة من الالمنيوم AA2024-T3 للتحليل الكيميائي والاختبارات الميكانيكية. تم لحام هذه العينات باستخدام التقنيات المذكورة أعلاه بأربعة سرع دورانية (2000 و 2500 و 3000 و 4000 دورة في الدقيقة) باستخدام أقطار لأداة اللحام (5 و 7 ملم) لإجراء اختبارات القص الشدي. أجري فحص الصلادة الدقيقة على طول المقطع العرضي للعينات الملحومة في أفضل الظروف وكذلك الفحصوصات المجهرية. أظهرت نتائج المقارنة أنه في سرعات الدوران (2000 و 4000 دورة في الدقيقة) في كلتا حالتي أداة اللحام (5 و 7 ملم) ، كانت قوة القص الشدي القصوى أعلى قليلاً من تلك السرع الأخرى. كذلك ، كانت قوة القص الشدي النهائي أعلى عند سرعة 3000 دورة في الدقيقة لأداة اللحام 7ملم. أظهرت نتائج الصلادة الدقيقة شكل W في أفضل ظروف لحام. وأخيرا ،اظهر الفحص المجهري المناطق الرئيسية لوصلة اللحام.


Article
Assessment the Engineering Characteristics of the Smear Zone around PVDs Using Laboratory Tests
تحديد الخصائص الهندسية للترب المشوهة حول المبازل العمودية باستخدام الفحوصات المختبرية

Authors: Ahmed Shakir Kamil --- Ala Nassir Aljorany
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2019 Volume: 25 Issue: 11 Pages: 67-81
Publisher: Baghdad University جامعة بغداد

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Abstract

Smear zone is usually formed around the prefabricated vertical drains (PVD’s) due to mandrel driving. The geotechnical properties of the soil in this zone exhibit significant changes that affect the performance of the PVD’s. The most relevant property in this respect is the coefficient of permeability. So far, no serious attention is paid to investigate the effects of shearing under large shear strains on the geotechnical properties of the soft soil in Fao region. In this study, an extensive laboratory testing program was conducted to assess the characteristics of the smear zone with an emphasis on the permeability coefficient of Fao soft soil. The results show that the permeability of the smear zone is about 70% of the horizontal permeability of the intact soil. An attempt was made to estimate the extension of the shearing zone in the direct shear test. The analysis results indicate that thickness of the shearing zone is about (2.4) cm.

المنطقة المشوهة عادة ما تتكون حول المبازل العمودية بسبب اختراق المكبس للتربة. الخصائص الجوتكنيكية للتربة تظهر تغيرا كبيرا وهذه التغيرات تؤثر على اداء المبزل العمودي. الخاصية الاهم في هذه الحالة هي معامل نفاذية التربة. لغاية الان لا يوجد انتباه حقيقي لدراسة تأثير القص بانفعال قصي كبير على الخصائص الجيوتكنيكية للتربة الناعمة في منطقة الفاو. في هذه الدراسة تم عمل برنامج فحوصات مختبرية موسع لتحديد الخصائص المنطقة المشوهة مع التركيز على معامل نفاية تربة الفاو. النتائج اظهرت بان معامل نفاذية المنطقة المشوهة يعادل حوالي 70% من نفاذية التربة غير المشوشة. تم القيام بمحاولة لتحديد سمك منطقة القص المتكونة من فحص القص المباشر. تحليل النتائج اظهر سمك المنطقة المشوهة يعادل حوالي 2.4 سم.


Article
SHEAR CAPACITY OF SELF COMPACTING CONCRETE DEEP BEAM UNDER CONSTRAINED AXIAL LOADS

Authors: Wissam Khadum Alsaraj --- Sarra’a Dhiyaa Jaafer
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 5 Pages: 12-25
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The main objective of this paper is to study the shear capacity of SCC reinforced concrete deep beams subjected to axial load. Seven simply supported deep beams casted by using SCC mix with steel fibers and tested. All these beams have dimensions of 1300mm length, 350mm high, and 150mm width and have been subjected to constant axial force with value (100) kN and then subjected to two point loads. The variables of this work are (shear span/depth (a/d), vertical shear reinforcement (ρv), and horizontal shear reinforcement (ρh) to study their effects on first crack and ultimate loads , and mid span deflection.


Article
VALIDATION OF FINITE ELEMENT MODELING FOR RECTANGULAR REINFORCED CONCRETE BEAMS WITH WEB OPENINGS

Author: Ahlam Sader Mohammed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 3 Pages: 89-98
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The present paper aims to validate ABAQUS finite element model to analysis the rectangular reinforced concrete beams in order to study web opening effect on the shear, and ultimate strength of these beams. The validation has been achieved through comparison of load-- deflection curves obtained from the finite element model with those of experimental works of another researcher. The dimensions and flexural reinforcement of the beams were kept the same. The investigated test parameters were the size and the location of the openings. Comparison between load-deflection curves obtained from finite element model with those of experimental works indicates good agreement such that the proposed model can be adopted in future for further studies.


Article
Assessment the Shear Behavior of Sustainable Thick Hollow Core Slab Using Experimental and Nonlinear Finite Element Modelling

Authors: Yousif Nassif Sabr --- Dr. Husain Khalaf Jarallah --- Dr. Husain Khalaf Jarallah
Journal: Anbar Journal of Engineering Sciences مجلة الأنبار للعلوم الهندسية ISSN: 19979428 Year: 2019 Volume: 8 Issue: 1 Pages: 35-43
Publisher: University of Anbar جامعة الانبار

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Abstract

This investigation provides experimental results and nonlinear analysis by using finite element model of thick hollow core slab made from recycled lightweight material. Four hollow core slabs specimens were cast and tested in this investigation with dimensions (1200mm length, 450mm width and 250mm thickness). The crushed clay brick was used as a coarse aggregate instead of gravel. The iron powder waste and silica fume were used in order to increase the compressive strength of concrete. The techniques reduction hollow length and use shear reinforcement were used to improve shear strength and avoid shear failure. The specimens were tested by applying two-line load up to failure. The experimental results were showed these techniques were resisted the shear failure significantly and works to change failure mode from shear to flexural failure. Finite element computer software program (ANSYS) was used to analysis hollow core slabs specimens and compare the experimental results with the theoretical results. Good agreement have been obtained between experimental and numerical results.


Article
Evaluation the Geotechnical Properties of Oil-Polluted Soil from Two Selected Areas in Thi-Qar Governorate-Iraq
تقييم الخواص الجيوتكنيكية للترب الملوثة بالنفط من منطقتين مختارتين في محافظة ذي قار/العراق

Authors: Nesreen Kurdy Al-Obaidy, --- Hussein Shaia
Journal: Univesity of Thi-Qar Journal مجلة جامعة ذي قار العلمية ISSN: 66291818 Year: 2019 Volume: 14 Issue: 1 Pages: 17-31
Publisher: Thi-Qar University جامعة ذي قار

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Abstract

Oil pollution of the soil due to a leakage in oil tubes, transportation of products, or during oil excavations can change the soil physical and mechanical, chemical, and biological properties. Consequently, the soil may or may not be eligible for engineering construction projects and it may need a significant treatment. Therefore, it is required to have a better understanding of the general behavior and the corresponding geotechnical properties upon pollution particularly for those areas associated with oil explorations and industry like Thi-Qar Governorate. Fine and coarse soils from two sites at the University of Thi-Qar are artificially contaminated with oil products ranging from 0% to 10% of their dry weight. Testing programs have been performed on both soils included conventional tests such as grading, Atterberg limit, vane shear and direct shear tests. To achieve a fair comparison, the outcomes are directly compared to those of the original uncontaminated soil. The final results of this study indicated the variations in the soil properties for the studied soils upon contamination and addressed the concept behind such behavior.

يمكن للتلوث النفطي في الترب الناتج عن تسرب في أنابيب النفط ، أو عن نقل المنتجات النفطية، أو أثناء التنقيب عن النفط أن يغير خصائص التربة الفيزيائية والميكانيكية والكيميائية والبيولوجية. وبالتالي ، قد تكون التربة أو قد لا تكون مؤهلة لمشاريع البناء الهندسية ، وربما تحتاج إلى علاج كبير. لذلك ، يجب أن يكون هناك فهم أفضل للسلوك العام والخصائص الجيوتقنية لتلك التربة عند التلوث خاصة لتلك المناطق المرتبطة باستكشافات النفط والصناعة النفطية مثل منطقة محافظة ذي قار.في هذه الدراسة تم اخذ نموذجين من التربة الناعمةوالخشنة من موقعين مختلفين في جامعة ذي قار وتم تلويثهما اصطناعيا بمنتجات نفطية وبنسب تتراوح من صفر٪ إلى 10٪ من وزنها الجاف. وقد أجريت برامج الاختبار على كلا النموذجين وقدشملت الاختبارات التقليدية مثل التدرج الحبيبي ، وحدود اتيربيرك اختبار قص الريشة، واختبار القص المباشر. ومن اجل تحقيق مقارنة عادلة ، فقد تمت مقارنة نتائج التربة الملوثة مباشرة بتلك الخاصة بالتربة الأصلية غير الملوثة. أشارت النتائج النهائية لهذه الدراسة إلى الاختلافات الملحوظة في خصائص التربةالمدروسة قبل وبعد التلوث ، وتناولت المفهوم الكامن وراء هذا السلوك.


Article
Collapsibility Of Gypseous Soil In Tikrit city – Salahaddin Governorate-Iraq: case study
انهيارية التربة الجبسية في مدينة تكريت – محافظة صلاح الدين – العراق : الدراسة الحالية

Author: Khaled Ahmed Abduallah Alhadad
Journal: journal of kerbala university مجلة جامعة كربلاء ISSN: 18130410 Year: 2019 Volume: 17 Issue: 2 Pages: 1-14
Publisher: Kerbala University جامعة كربلاء

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Abstract

This investigation is carried out to study the phenomenon of collapsibility that occurrence in the city of Tikrit in Salahaddin Governorate at located 170 km north of Baghdad . The physical indexes and engineering properties tests were to used determine the natural water content, Atterberg limits, grain size distribution of soils, shear strength and consolidation test .The grain size distribution of soil showed the silt percentage is higher than those of clay and sand. They are composed of silt that represents ( 52 - 60 )% of the soil and ,Clay represents ( 34 - 45 ) % of the soil. The liquid limits(L.L) values ranges between ( 23 – 37 )%, While the plastic limit (P. L.) values ranges between ( 21-31 )% and Plasticity index (P.I) values ranges between ( 6 - 7)%.The moisture content values between (1.9 - 2.2) , are classified low, due to high gypsum percentage, which absorbed most of the amount of water, and incorporated into its molecular structure. Direct shear test shows that the cohesion values (C),range between ( 40 – 51) kN/m2, While the internal friction angle( Ø°) of the soil ranges between ( 25°- 33°),The consolidation parameters showed that the compression index (Cc)values ranges between (0.040-0.055),swelling index (Cr) values ranges between (0.003-0.015),and Pre- consolidation pressure (Pc) values ranges between (125-275) kN/m2. The Collapse potential (Cp*100) values ranges between (1.41 – 1.85) kN/m2, as a moderate trouble. The chemical tests of the soil showed that the percentage of Total soluble salts (T.S.S)range between (24.24 - 56.63)%,While the gypsum content range between%(22.35 -55.15)%,which play a role in soil properties fluctuation Therefore, gypsum soils should be studied during investigation phase, to assess the soils ability to prevent failure in future.

اجريت هذه الدراسة للتحري عن ظاهرة الانهيارية التي حدثت في مدينة تكريت محافظة صلاح الدين ، والتي تقع 170 كم شمال بغداد . تم اجراء الفحوصات الفيزيائية والهندسية ، لاحتساب المحتوى الرطوبي ، وحدود اللدونة ، التوزيع الحجمي للتربة ، مقاومة القص، الانهيارية ،و الانضمام . اظهرت نتائج التدرج الحجمي ان نسبة الغرين للنماذج المفحوصة هي اعلى من نسبة الطين والرمل ، اذ تمثل 52 – 60 % من مكونات التربة ، والطين بنسبة 34 – 45 % . تراوحت قيم حد السيولة23 – 38 %، بينما قيم حد اللدونة 21 – 31 % و قيم دليل اللدونة 6 – 7 %. اصنافها طينية غرينية , غرينية لاعضوية واطئة اللدونة . كانت قيم المحتوى الرطوبي 1.9 – 2.2 %. يصنف على انه واطيء ، وسبب انخفاضه لاحتواء التربة على نسب عالية من الجبس الذي يستحوذ على معظم كمية الماء ويدخلها في تركيبه الجزيئي تظهر نتائج فحص القص المباشر. تراوحت قيم مقاومة التماسك 40 – 51 كيلو نيوتن / م2 وقيم زاوية الاحتكاك الداخلي 25°- 33° ، قيم معاملات الانضمام ، دليل الانضغاط 0.040 – 0.055 , معامل الانتفاخ 0.003 – 0.015. تراوحت قيم نسب الفجوات 0.42 – 0.62 %، قيم الضغط الفعال 370.5- 528 كيلو نيوتن / م2 وقيم ضغط الانضمام المسبق 125 – 275 كيلو نيوتن /م2 ، تراوحت نسبة الافراط بالانضمام 1.437 – 4.224 . تراوح معامل الانهيارية 1.41 – 1.85 كيلو نيوتن/ م2 . تم تصنيف المشكلة انها متوسطة . اظهرت نتائج التحاليل الكيمائية ، ان قيم مجموع الاملاح الذائبة 24.24 – 56.63%. تراوحت قيم محتوى الجبس 22.35 – 55.15% ، الذي يلعب دورا في تغيير خواص التربة ، لذلك يجب دراسة التربة الجبسية خلال التحريات ، لتقييم قابلية الترب لمنع الانهيارات مستقيلا .

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