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Structural Behavior of HS-SC Reinforced Concrete Beams with Longitudinal and Transverse Openings Strengthened with CFRP Laminates
السلوك الإنشائي للعتبات الخرسانية المسلحة عالية المقاومة ذاتية الرص ذات الفتحات الطولية والجانبية المقواة بصفائح ألياف الكربون بالبوليمرية

Authors: Hussain Dhafer AbdulJabbar --- Yaarub Gatia Abtan
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 5 Pages: 48-67
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Service runs had produced several shortcomings when congested in one place. So, using longitudinal and transverse opening in beams (BLTO) was creative solution for the purpose of serve those runs with other benefits, especially when utilized high strength self-compacting concrete (HS-SCC). To control cracks in web opening regions which lead to possible leakage, carbon fiber reinforced polymer (CFRP) laminates was significant strengthening system to realize that purpose. This study examined the behavior of thirteen reinforced concrete (RC) beams. These beams were involved into three groups. All beams were identical in dimensions, reinforcement, concrete type, and hole dimensions. The evaluation is used to elect the optimum hollow core section, position effect of web openings with fixed hollow core section, and effect of strengthened web openings. Due to recorded load capacity, a reduction was produced by hollow core position at mid and bottom section by about (2%-14%), respectively, with comparing by solid section. Therefore, the optimum hollow core section was when it locate in mid beam section which used to unify BLTO sections. BLTO types indicated different loading data according to web opening position. The decrement of opening provision was about (20.4%) by compared with hollow beam (without web-opening) and about (22%) by compared with solid beam. The optimum BLTO is when the web opening located in mid-shear zone, while the critical one recorded in web opening position in mid-span and near supports in same BLTO. Presence of CFRP system in same BLTO copy had enhanced beam resistance by about (29%) and prevents cracks to reach in web opening or with minimum hairline cracks without delaminating problem. The registered failure mode of all beams was contained two main type, suddenly flexural failure in compressive zone by concrete cover crushing and flexural-shear failure. Additionally, local failure occurred at central CFRP strips by ripping-off concrete cover through the edges of it.


Article
Experimental Study to Investigate the effect of Longitudinal and Transverse Openings on the Structural Behavior of High Strength Self Compacting Reinforced Concrete Beams

Authors: Hussain Dhafer AbdulJabbar --- Yaarub Gatia Abtan
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 1 Pages: 66-79
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Service runs considered as a major nerve of any building. Thus, beam with longitudinal and transverse opening (BLTO) was creative solution for the purpose of serve those runs with other benefits, especially when utilized high strength self-compacting concrete (HS-SCC). This study examined the behavior of eight reinforced concrete (RC) beams. These beams were involved into two groups. All beams had identical in dimensions, reinforcement, concrete type, and hole dimensions. The evaluation used to elect the optimum hollow core section, and position effect of web openings with fixed hollow core section. Due to recorded load capacity, a reduction was produced by hollow core position at mid and bottom section by about (2%-14%), respectively, with comparing by solid section. Therefore, the optimum hollow core section was when it locate in mid beam section which used to unify BLTO sections. BLTO types indicated different loading data according to web opening position. The decrement of opening provision was about (20.4%) by compared with hollow beam (without transverse opening) and about (22%) by compared with the solid beam. The optimum BLTO was when the web opening located in mid-shear zone, while the critical one recorded in web opening position in mid-span and near supports in same BLTO. The registered failure mode of all beams was contained two main types, suddenly flexural failure in compressive zone by concrete cover crushing and flexural-shear failure.


Article
Shear Behavior of RC Deep Box Beams Strengthened Internally by Transverse Ribs
سلوك القص للعتبات الخرسانية المسلحة الصندوقية العميقة المقواة داخليا بالأضلاع المستعرضة

Authors: Ali Hameed Aziz عـلي حميد عـزيز --- Yaarub Gatia Abtan .يعـرب كاطـع عبطـان --- Ruaa Yousif Hassan رؤى يوسف حسن
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2015 Volume: 19 Issue: 4 Pages: 148-169
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This research presents an experimental study of shear behavior of RC deep box beam strengthened internally by reinforced concrete transverse ribs. Eight beam specimens were tested, six box-deep beams and two solid-deep beams. The effect of type of concrete (NSC and SCC) and the number of internal cells on the behavior of deep box beam were tested. All beams were (2000mm) long and have been tested over a clear span of (1900mm) with a width of (450 and 200 mm) for top and bottom flanges respectively and (500mm) depth, the shear span-depth ratio (a/d) was (2) and longitudinal reinforcement ratio (ρ) was (0.00835). All beam specimens were simply supported under the effect of single point loading at mid span. The beam length, shear span-depth ratio (a/d), longitudinal and transverse reinforcement were kept constant for all tested beams. Test results indicated that all tested beams failed by shear and the failure took place by diagonal splitting mode for all tested beams except one beam, where its shear failure took place by diagonal compression mode. The results reveal that as (fʹc) increased from (30.7 MPa) to (58 MPa), increase in the first diagonal cracking load of (solid, one cell, two cells, and four cells) beams were about (17%, 27%, 23%, and 24%) respectively. Also, It was found that as (fʹc) increased from (30.7 MPa) to (58 MPa) increase in the ultimate load of (solid, one cell, two cells, and four cells) beams were about (63%, 56%, 45% and 59%) respectively. Test results indicated, also, that the box-deep beams which have two cells and four cells have the highest first diagonal cracking and ultimate loads as compared with box-deep beam which has one cell.

يتناول البحث الحالي دراسة عملية لسلوك القص للعتبات الخرسانية المسلحة العميقة الصندوقية المقواة داخليا بالاتجاه العرضي بواسطة أضلاع خرسانيه مسلحه. تم فحص ( 8 ) عتبات, قسمت إلى ستة عتبات خرسانية صندوقيه وعتبتين خرسانيتين صلدة, لدراسة تأثير كل من نوع الخرسانة ,حيث تم استخدام الخرسانة العادية بمقاومه انضغاط ( (30.7 MPa و الخرسانة الذاتية الرص بمقاومه انضغاط 58 MPa)), وعدد الخلايا cells)) المجوفة داخل العتبات الصندوقية على سلوك العتبات العميقة الصندوقية. جميع العتبات كانت بطول (2000mm) وقد تم اختبارها تحت فضاء (1900mm) وعرض (200 and 450 ) لكل من الشفة (Flange) العليا والسفلى على التوالي وبعمق كلي (500mm),وكانت نسبه فضاء القص إلى العمق الفعال (a/d) تساوي(2) ونسبة حديد التسلح الطولي (0.00835) .جميع العتبات المفحوصة كانت ذات إسناد بسيط وتحت تأثير حمل مفرد (في المنتصف) حتى الفشل. تم الإبقاء على طول العتبة, نسبة فضاء القص إلى العمق الفعال (a/d), ونسبة حديد التسلح الطولي وتسليح القص دون تغيير لكافة العتبات المفحوصة. اشارت نتائج الفحص الى ان جميع العتبات المفحوصه فشلت بالقص وحصل الفشل نتيجة التشقق القطري لجميع العتبات المفحوصه ما عدا عتبه واحده حصل فيها فشل بالقص نتيجة الانضغاط القطري . اظهرت النتائج انه بزيادة مقاومة انضغاط الخرسانه من (30.7 ميكاباسكال) الى (58 ميكاباسكال) كانت الزياده في حمل الشق القطري الاول بحدود (17%،27%،23% و 24%) للعتبات الصلده و ذات التجويف الواحد وذات التجويفين وذات الاربعة تجويفات على التوالي. كذلك، اظهرت النتائج، انه بزيادة مقاومة انضغاط الخرسانه من (30.7 ميكاباسكال) الى (58 ميكاباسكال) كانت الزياده في الحمل الاقصى بحدود (63%،56%،45% و 59%) للعتبات الصلده و ذات التجويف الواحد وذات التجويفين وذات الاربعة تجويفات على التوالي. ان العتبات الصندوقيه العميقه الحاويه على تجويفين او اربعة تجويفات تكون فيها احمال الشق القطري الاول و الاحمال القصوى اكبر عند مقارنتها مع العتبه الصندوقيه العميقه ذات التجويف الواحد.

Keywords

Shear --- Deep beam --- box beam --- strengthening --- NSC --- SCC --- Rib.

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