International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 09 Issue: 05 | May 2022
p-ISSN: 2395-0072
www.irjet.net
A Parametric Study on Seismic Response of Flat Slab Diagrid Structure Bhavesh U. Rudani1, Dipak K. Jivani2, Ketan R. Abhani3 1M.E.
(Civil) Structural Engineering, Darshan Institute of Engineering and Technology College, Rajkot, Gujarat, INDIA. 2Associate Professor, Head of Civil Engineering Department, Darshan Institute of Engineering and Technology College, Rajkot, Gujarat, INDIA. 3Assistant Professor, Civil Engineering Department, Darshan Institute of Engineering and Technology College, Rajkot, Gujarat, INDIA. ---------------------------------------------------------------------***--------------------------------------------------------------------1.1 Objectives of the study Abstract - This study is relevant to seismic performance
of different types of flat slab diagrid structure. As flat slab have poor resistance to lateral loads & also the failure of flat slab buildings is mostly governed by the punching stresses at slabcolumn joints along the perimeter. For the study of such types flat slab structures, vertical columns are replaced by diagrid at the perimeter. In high rise structures use of exterior diagrid structural system proved to be more efficient in resisting lateral loads by axial action of its members. On the account of seismic response, time history analysis was carried out in ETABS computer code. The optimal uniform angle of diagrid for different types flat slab diagrid structure was suggested & various parameters such as time period, axial forces in diagrid, punching stresses in slab, max storey displacement, max storey drift & base shear were discussed. Diagrids are advantageous from structural as well as aesthetic point of view. Key Words: Types of flat slab, Diagrid, Seismic load, Optimal angle, Time history analysis
1. INTRODUCTION Flat slabs are the slabs which are supported directly on the columns omitting beams. It is a two-way slab bending in both the directions. To increase the shear strength of flat slabs different types construction can be done which are :Flat plate, Drop panel, Column head, with combined Drop panel & Column head. Flat slab have poor resistance against lateral loads due less lateral stiffness which results in excessive lateral displacement. Unbalanced moments concentration due to wind & earthquake loads near the edge columns is indeed a complex phenomenon. So, for the use of multi-storied flat slab structures, they must be equipped with lateral load resisting structural system. Recent studies shows that the Diagrid structural system is effectively used to resist lateral loads in Tall structures. In Diagrid structural system all forces are transferred through a node, generating axial forces in the diagonal columns as compared to moment resisting frame system, in which external forces are transferred through beam-column junction, creating bending moments in vertical columns. © 2022, IRJET
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ï± The main objective of the study is to understand the behavior of different types of flat slab diagrid structures using linear time history analysis. ï± To suggest the suitable angle of diagrid in Flat slab diagrid structure. ï± To study response of Flat slab diagrid structures with increase in height of the building. ï± To compare the results of different types of Flat slab diagrid building with normal Flat slab building. ï± To study the response of building in terms of different parameters which are Time period, Axial forces in diagrid, Punching Stresses in slab, Base Shear, maximum storey Displacement and maximum storey Drift.
2. REVIEW OF LITERATURE R.P. Apostolska, G.S. Necevska-Cvetanovska, J.P. Cvetanovska and N. Mircic (2008) Investigated the effects of designed modifications upon the dynamic characteristics as well as upon bearing and deformability of the flat-slab structures using time history analysis. The flat slab strengthened by perimeter beams and RC walls is having 40% less displacement and less fundamental period as compared to frame system. So, to limit the deformations in seismically prone areas & to increase the bearing capacity for flat slab structure under horizontal loads, modifications of such system are necessary by adding structural elements. Subhajit Sen, Yogendra Singh (2010) Carried out nonlinear static analysis of flat slab buildings, with and without considering the continuity of slab bottom reinforcement through column cages. The buildings was designed as per guidelines of IS 456:2000, ACI 318-08, EC 2:2004 and NZS 3101 (Part-1)-2006. In flat slab without edge beams, torsional portion of unbalanced moment causes excessive punching shear stress and design is governed by punching shear failure at exterior slab-column support while edge beams in flat slab transfer the unbalanced moment from exterior support reducing punching shear stress at slab column connection, which also reduces thickness of slab. Most of flat slab building are not ensuring Collapse ISO 9001:2008 Certified Journal
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