Shear behavior of rc beams with openings strengthened with steel plates / By Heba Mohamed Abo El Maaty Mohamed; Under the Supervision of Prof. Dr. Hany Ahmed Ali Abdalla, Prof. Dr. Ghada Diaa Abd Elhamed Ahmed

Thesis (M.Sc.) -Cairo University, 2023.

Bibliography: pages 76-78.

Openings in the reinforced concrete beams facilitate the passage of many essential
services in modern buildings. Structurally, it must be taken into account that the
presence of this opening will lead to problems related to the strength of the element that
contains the opening, such as the reduction of the beam strength, excessive cracks
around the opening zone, high stress concentration at the opening corners. The presence
of the opening will also change the behavior of the internal forces of the beam, and the
overall behavior will be more complicated, especially in shear behavior, which is
already a complex behavior because it is a sum of several mechanisms and internal
movements, so it is difficult to predict it accurately. This thesis aims to study the shear
behavior of reinforced concrete beams with openings strengthened with steel plates.
The experimental program was conducted in the materials lab of Housing and Building
National Research Center, consisting of six reinforced concrete beams containing
transverse openings. Several variables were studied, such as the presence or absence of
the opening, size and location of the opening, and the external strengthening of the
openings in some specimens using steel plates on both sides.



The results included the experimental results of the first crack load, the ultimate load,
the deflection values at different load levels, the strain values in concrete, the strain in
bottom longitudinal reinforcement steel, and stirrups. Finally, the experimental results
were compared with the results based on some assumptions in the codes that dealt with
the design of traditional concrete beams, for example, the Egyptian Code (ECP), the
American Concrete Institute (ACI) and according to the Canadian Standards (CSA).
The results showed that the presence of openings had an apparent effect on the shear
strength of the concrete beams, the nature of cracks and the type of final failure, where
it was clear that the difference in location and the increase in the size of the opening
affected the ultimate load of the beam and when comparing the beams with the
unstrengthened opening with the strengthened ones, it was found that the effect of
strengthening is practical on the ultimate load value or the nature, timing and shape of
the cracks.

تسهل الفتحات الموجودة في الكمرات الخرسانية مرور العديد من الخدمات الأساسية. وجود هذه الفتحة سيؤدي إلى مشاكل تتعلق بقوة العنصر الذي يحتوي على الفتحة. تمت دراسة العديد من المتغيرات ، مثل وجود أو عدم وجود الفتحة وحجمها وموقعها ، والتدعيم الخارجي للفتحات في بعض العينات باستخدام ألواح الصلب المثبتة على كلا الجانبين باستخدام مسامير. أظهرت النتائج أن وجود الفتحات كان له تأثير واضح على مقاومة القص للكمرات الخرسانية و طبيعة الشروخ حول منطقة الفتحة و نوع الانهيار النهائي و وجد أن تأثير التدعيم الخارجي للفتحات كان فعال بالنسبة لزيادة قيمة الحمل النهائي و طبيعة وتوقيت وشكل الشروخ الناتجة و مقارنة النتائج المعملية بالأكواد المختلفة.

Issued also as CD

Text in English and abstract in Arabic & English.