International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249-8958 (Online), Volume-9 Issue-2, December, 2019 841 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: B3975129219/2019©BEIESP DOI: 10.35940/ijeat.B3975.129219 Journal Website: www.ijeat.org Abstract: This research targets to maximize the ductility and strength of the reinforced concrete flat slabs. However, to be efficient, the shear reinforcement must be anchored well in the tension and compression zones of the slab. The test results on the slab-column connection models which provided with shear reinforcement are introduced in this study. The benefits of using shear reinforcement are to reduce the slab thickness, and to minimize both the cost and the total weight of the structure. Twelve flat slab specimens have been tested to study the effect of different types of steel RFT on the punching shear of the flat slab. The experimental parameters include no shear reinforcement which study the advantage of using tension RFT ONLY against punching shear, no shear reinforcement which study the advantage of using compression RFT against punching shear, shear RFT (Vertical Stirrups) which study the effect of using shear RFT with constant distribution 0.5d, and a new distribution of shear stirrups which study the effect of using new different width & spacing of vertical stirrups. The twelve specimens were loaded with concentrated load at the mid span until failure. The general behavior of the deformation of the tested slab specimens was examined and recorded (cracking, deflection, and strain in both steel and concrete). A comparison established between the experimental and the numerical- theoretical results obtained from applying the punching shear strength formula given in design codes, and finite element modeling analysis; ABAQUS 2017 software package was used for this analysis. A total of six building codes were examined with regard to their provisions concerning the punching shear. A comparison had been made between the research test results and the codes equations to improve the methods of the analysis about the flat slabs. This study aimed to improve the punching shear capacity of flat slab which leads to more accurate results compared with the codes predictions. To achieve this aim, an experimental and numerical study was carried out for this investigation. Keywords: Flat Plates; Punching Shear; Slab-Column Connection; Shear Reinforcement; Vertical Closed Stirrups. I. INTRODUCTION The most economical system in reinforced concrete structures is the flat slab. It provides flexibility in the architectural design; which maximize the clear space, minimize the building height, and minimize the construction time. However, Revised Manuscript Received on December 30, 2019. * Correspondence Author Ahmed M. Issa *, lecturer Assistant, Housing & Building National Research Center, HBRC, Giza, Egypt. Email: engahmed3essa@gmail.com Mohamed M. Salem, Associate Professor, Housing & Building National Research Center, HBRC, Giza, Egypt. Email: mm.aladawy@gmail.com Mohamed T. Mostafa, professor, Cairo University, Giza, Egypt. Email: talatmostafa@gmail.com Hamed M. Hadhoud, professor, Cairo University, Giza, Egypt. Email: hamedhadhoud@yahoo.com Hatem H. Ghith, professor, Housing & Building National Research Center, HBRC, Giza, Egypt. Email: hatem_ghith@hotmail.com © The Authors. Published by Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) the punching failure due to the unbalanced shear and moment transfer in column slab connection is considered a critical problem in flat slab system. The unbalanced moment is transferred by the combination of flexure, shear, and torsion in the slab next to column faces. When shear stresses due to shear forces and moment transfer in the region of flat slab next to column become too high, a punching failure will occur. Since many years ago, punching has been a problem to engineers who tried to fully understand it. It does not matter how many experiments, analysis, and models were made which relied on empiric results that did not describe the totally phenomenon. The test parameters which used are the reinforcement properties, the geometry of the slabs, aggregate size, and loading modes. Although all of these were planned in an intelligent way, providing a huge range of results, it is impossible to cover all parameters. However, this system has a lot of problems which is the failure of the slab’s punching due to the stresses concentration around column slab connections. This failure type is critical due to its brittle nature. At the time, the failure of the shear punching occurred; the strength of the structure is typically minimized due to the disconnection between column and slab therefor joint connection failure will occurs. In the structural analysis of flat slabs, the punching shear strength has a noticeable effect on the slab design parameters including slab thickness, the supporting column dimensions, flexural steel, and shear reinforcement. It was the start of using flat slabs at the beginning of 20th century, which directly supported by columns led to several researches to be started on the punching strength of flat slab. At first, research mainly covered flat slabs without punching shear reinforcement, followed by researches on flat slabs with punching shear reinforcement. Depending on the beam design, bent-up bars were the first shear reinforcement which used [1]. After that, new designing systems have been developed such as shear studs and several stirrup systems. The punching shear reinforcement system changing was always depended on researches about this subject resulting in developing of new techniques of various shear reinforcement systems. There are different types of punching failures had been recognized in flat slab of slab-column design systems; First failure called "beam-type" or "one-way" punching failure, as shown in “Fig.1.a” that known as inclined crack widening toward the total slab width. Second failure called "punching" or "two-way" shear failure which takes control in the designing of flat slab generally, as shown in “Fig.1.b” which known as pyramid-shape surface or truncated cone round the column. While the ordinary reinforced slabs, the inclination angle of pyramid surface against the failure plane is ranges around 20 to 45 degrees (Min-Yuan Cheng) [2]. Based on a thesis research about the two-way punching shear action published by. Performance of Shear Reinforcement against Punching Shear Loads Ahmed M. Issa, Mohamed M. Salem, Mohamed T. Mostafa, Hamed M. Hadhoud, Hatem H. Ghith