Seismic Fragility Curves for RC Flat Slab Buildings with and Without Infill

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Rapid urbanization leads to more demand for construction of commercial buildings in Indian cities. The ease construction and more space demand of buildings are constrained in conventional buildings. To overcome constrained, the flat slab buildings evolved and practiced recent time in urban cities. It is becoming more popular for multistoried commercial buildings but experiences larger displacements under lateral load effect caused by earthquakes. These buildings need urgent to assess the vulnerability of buildings. In this fragility analysis is carried out, and it is useful for the evaluation of the probability of structural damage due to earthquakes as a function of ground motion indices. This paper is an attempt made to develop the fragility curves for seven-storey RC commercial buildings and a comparison made between the bare frame, flat slab, flat slab with drop, flat slab with drop and perimeter beam buildings without and with exterior infill walls. The building models are analyzed using ETABS software and designed as per IS 456. In this, infills are considered along the perimeter of the plan of the building and no infill in ground storey. The infill wall is modelled as equivalent diagonal strut model. The Auto hinges are assigned for both beam and column members. Pushover analysis has been performed on the building models using ETABS software. Yield and ultimate spectral displacement and spectral acceleration are obtained from capacity curves. For the development of fragility curves, HAZUS methodology has been used. Fragility curves are developed for all the eight building models and compared the probability of damage of structures for bare frames and open ground storey buildings. In this assumed, the expected intensity ground motion is considered as seismic zone PGA values. It is observed that in considered flat slab models, flat slab with drop and perimeter beam building is showing minimum probability of damage results in both with and without infill for given intensities.