www.tjprc.org SCOPUS Indexed Journal editor@tjprc.org SEISMIC BEHAVIOUR OF FLAT SLABS IN MULTI-STOREY BUILDINGS NIRANJAN CHAUDHARY 1 & NITIN VERMA 2 1 M. E. Scholar, Department of Civil Engineering, Chandīgarh University, Mohali, Punjab, India 2 Assistant Professor, Department of Civil Engineering, Chandigarh University, Mohali, Punjab, India ABSTRACT The growth of population has influenced the construction of multistory buildings day by day. The construction of the building structures with conventional RC slabs are in the public eye since many decades. Although it has more stiffness and minimizes the large moments occurred due to the applied loads, it does not have the advantages in terms of architectural flexibility, easier formwork and shorter construction period compared to the flat slabs. This developing technique of flat slabs construction improves aesthetical and structural aspect of tall building, offices, hospitals, shopping malls etc. As this is considered to be beamless slab, it has less shear strength and less stiffness compared to the conventional slabs. Due to its huge advantages, it is common in both the construction of regular and irregular buildings nowadays. The main motive of the present work is to compare and observe the seismic behavior of G+13 storey of regular and different plan irregular buildings (Plus, T and U shape) by using different types of flat slabs (flat plate, drop panel, column head and combination of column head & drop panel) with the help of E-tabs 17.0.1 software. Later, conventional slab was adopted in the both regular & irregular models and analyzed in the similar way and compared with flat slab models intended for zone V. The nonlinear time history method was carried out to observe the different parameters like storey displacement, storey drift, base shear and time period following the guidelines of IS 1893 (Part 1): 2016. KEYWORDS: Flat Plate, Drop Panel, Column Head, Nonlinear Time History Analysis, Irregular Building, Storey Displacement Received: Jun 09, 2020; Accepted: Jun 29, 2020; Published: Aug 06, 2020; Paper Id.: IJMPERDJUN2020645 INTRODUCTION The construction of buildings using conventional RCC slabs is common since many years. Although it increases the shear capacity and stiffness of the structure; it is being replaced by the developing construction technique (i.e. flat slabs) which was invented by C.A.P. Turner in U.S.A in 1906. These slabs are resting directly on the columns due to which loads are directly transferred to columns. These are considered to be beamless slabs and claim 20% cost reduction in comparison to conventional RCC slabs. It can be designed and built by both the conventional RCC and post-tensioning. Due to the several advantages like aesthetic appearance, better illumination, flexibility in room layout, shorter construction period, easier formwork, placement of reinforcement has become easier in this type of construction. Since the slab does not have beams, it results in plain ceiling thus providing the aesthetic view from architecture point of view. These types of slabs avoid the beam column clogging due to its speedy and typical type of construction. These are considered to be more flexible than the conventional slabs thus becoming more vulnerable to seismic loading conditions. Generally, two types of failure (i.e. flexure failure and punching shear failure) exists in this type of system. This punching shear is about to occur once the entire shear force goes above the shear resistance of the slab and hence the slab gets pushed down just about the column. This leads to the breakage of the column through the part of the encircled slab and to overcome this type of failure, the additional Original Article International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN(P): 2249–6890; ISSN(E): 2249–8001 Vol. 10, Issue 3, Jun 2020, 6793–6806 © TJPRC Pvt. Ltd.