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Article
Flexure Behavior of Hybrid Continuous Deep Beam Strengthened by Carbon Fiber Reinforced Polymer

Authors: Hayder M.K.Al-Mutairee --- Hussein Ali Al- Hamdani
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2017 Volume: 25 Issue: 5 Pages: 1580-1592
Publisher: Babylon University جامعة بابل

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Abstract

This study present an experimental investigation for overall flexure behavior of reinforced concrete continuous deep beams (RCCDB) made of hybrid concrete, normal strength concrete (NSC) and high strength concrete (HSC) at different location and percentage.The experimental work includes testing of sixteen specimens of RCCDB under two points loads. The effects of HSC layer thickness and CFRP on strength of RCCDB had been studied. The experimental results showed that the strengthening of RCCDB by HSC layer from top is better than from bottom, where the increment in the ultimate flexural strength increased by (14,21,27)% for top strengthening and (12,15,13)% for bottom strengthening for (25,50,75)% thickness of total depth of beam respectively. The optimal strengthening of RCCDB by HSC layer at top was of 25%. The results also proved that the strengthening of hybrid RCCDB by (10,15)cm CFRP strip at the bottom for flexure gave increment in the ultimate strength by (32, 29)% respectively, and the strengthening by CFRP strip for flexure at the bottom is better than at top for hybrid RCCDB. The shear strengthening of hybrid RCCDB increases the ultimate strength by 23.4% and 13.8% if the strengthening has O and U shape respectively

يتضمن هذا البحث دراسة تصرف الانثناء العام للأعتاب الخرسانية الهجينة العميقة المستمرة المتكونه من خرسانه طبيعة المقاومة وخرسانة عالية المقاومة لنسب ومواقع مختلفة من المقاطع . تضمن الجزء العملي من البحث فحص ستة عشر عتب مستمر هجين تحت تأثير نقطتي تحميل لدراسة عمق وموقع الخرسانة عالية المقاومة وكذلك تأثير التقوية بواسطة الالياف الكربونية. اظهرت النتائج المختبرية ان تقوية الاعتاب الخرسانية المستمرة العميقة الهجينة المتكونة من خرسانة عالية المقاومة في الطبقات العليا افضل من تقويته في الطبقات السفلى , حيث كانت الزيادة في تحمله الاقصى للانثناء (27,21,14)% للأعتاب التي تم تقويتها من الاعلى و (12,15,13)% للأعتاب التي تم تقويتها من الاسفل لنسب تقويه هي (75,50,25)% من العمق الكلي للعتب على التوالي.ان أفضل تقويه للأعتاب الخرسانية الهجينة المستمرة هي بوضع 25% خرسانة عالية المقاومة في الطبقة العليا.اما بالنسبة للاعتاب المقواة بالألياف الكاربونية (المقواة بشرائح بعرض 15و10 سم) من الاسفل فقد اعطت زيادة في مقاومة الانثاء القصوى بنسبة (29%و32%) على التوالي وأكدت النتائج إن وضع الاياف الكاربونيه في الاسفل افضل من وضعها في الاعلى من اجل الحصول على مقاومه اعلى للانثناء لهذا النوع من الأعتاب. ان تقويه القص للاعتاب الخرسانية الهجينة العميقة المستمرة يؤدي الى زيادة المقاومة بنسبة 23.4% و 13.8% اذا ما كانت التقوية على شكل حلقي وحرف U على التوالي .


Article
EXPERIMENTAL STUDY OF SELF-COMPACTING REINFORCED CONTINUOUS DEEP BEAMS

Authors: Abdul_Qader Nihad Noori --- Adnan Falih Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 1 Pages: 43-65
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Test results of twelve reinforced self-compacted concrete two-span deep beams casted by using self-compacting concrete are reported. The main variables studied were shear span-to-overall depth ratio (a/h), concrete strength (fʹc) and the amount of vertical shear reinforcement ratio (ρv). All specimens had the same dimensions and main flexural reinforcement. Tests pointed out that all beams failed in shear with diagonal splitting mode. It was found that shear span to overall depth ratio (a/h) effects the load carrying capacity of beams such that a decrease of 50 % in that ratio from 1 to 0.5, the cracking load (Pcr) and ultimate load (Pult) increase by average ratios of 29% and 25% respectively. The concrete compressive strength (fʹc) are also had a noticeable influence on the continuous deep beams behavior such that increasing (fʹc) to almost twice from (33.81 to 67.8) MPa led to an increase in the cracking load (Pcr) and ultimate load (Pult) by average ratios of 12.75% and 16.5% respectively. When (ρv) is increased by 80% from (0.25% to 0.45%) a better increase shear capacity of both NSCC & HSCC deep beam having (a/h) ratio of 1.0 (enhancement reached to18.56% and 23.1% respectively) as compared to the reference beams without shear reinforcement (ρv=0).S


Article
EFFECT OF WEB REINFORCEMENT ON SELF-COMPACTING REINFORCED CONCRETE CONTINUOUS DEEP BEAMS

Authors: Abdul_Qader Nihad Noori --- Adnan Falih Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 4 Pages: 211-228
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The main purpose of this experimental study is to investigate the behavior and strength of self-compacting reinforced concrete continuous deep beams with and without web reinforcement. The program included cast and test of five beam specimens, in which the vertical and horizontal shear reinforcement were varied. All specimens had the same length, depths and main flexural reinforcement ratio and they were subjected to concentrated vertical loads only. It was found that the addition of vertical shear reinforcement with minimum ratio (ρv=0.25%) increases the both of cracking and ultimate loads by about 10%, When vertical shear reinforcement is increased by about 80% (from 0.25% to 0.45%) a noticeable increases in the ultimate load capacity is observed (the enhancement reached to 18.6%).When providing horizontal web reinforcement of (ρh=0.343%) in addition to the provided vertical shear reinforcement (ρv=0.25%), the cracking and ultimate loads increased by about (17.5% and 25%) respectively, while the previous ratios of the cracking and ultimate loads increased to (20% and 33%) respectively when vertical shear reinforcement increased to (ρv=0.45%).

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