SEISMIC EVALUATION OF FLAT SLAB BUILDINGS WITH SHEAR WALL

Abstract

Use of flat slab is promoted highly these days due to its ease in construction, economy, faster construction and slip forms can be used in their construction. Flat slab construction gives lesser floor to floor height for the same head-room. Generally flat slab-column system is designed in lower seismic zone areas for resisting gravity loading. Its performance reduces drastically as this system is introduced to lateral loadings of higher seismic zones. Thus to resist this lateral loading.this system is provided with lateral load resisting elements such as shear walls or shear —wall —cores. In the current study, behavior of flat slab-column system which was designed safe for resisting gravity loading is studied for lateral loading of Zone IV and Zone V as defined in IS:1893-2002. Along with this how its behavior varies and improves with the introduction of shear wall is studied using static non-linear analysis i.e. Push over analysis and results are presented for the same. The 3-D model of flat slab structure is done using SAP-2000 Vii. The buildings with 8,12 and 16 storey with and without Shear wall are studied. For modeling of flat slab, Explicit transverse torsional member method is used. For modeling of Shear wall, Wide column method is used. Provisions of FEMA 356, ATC — 40 and ACI 318-05 are used to define user defined hinge properties. On the basis of presented results it can be concluded that flat slab structure doesn't behave like conventional beam column structure. With the introduction of shear wall, the behavior of flat slab structure improves drastically. Also here the behavior of structure with 0.5 and 1.0% as floor area of shear wall is studied. And it has been concluded that with increase in percentage of shear wall until a limit the performance of the flat slab structure improves.