SEISMIC PERFORMANCE OF RC FLAT SLAB STRUCTURE WITH DIFFERENT TYPES OF STEEL BRACING

Dakshayani S, Chaithra N

Abstract: One of the lateral load opposing frameworks in multi-storey structures is Steel brace frame. The resistance of the structure which enhances against horizontal forces by expanding its stiffness and stability is Steel bracing system in RC multi-storey building is conservative, simple to set up, involve less space and give obliged quality and inflexibility. X, K, inverted V, and Diagonal and knee bracings are distinct types of bracing systems. Flat slab reinforced buildings have exhibit many dominance over conventional type of beam column building. However, the effectiveness of structure in flat slab construction is inferior in performance under earthquake loading. Flat slab requires the simple formwork which usually result in an economical construction. In present study, a G+9 storey building is analysed for seismic zone IV as per IS 1893: 2002 using ETABS software. The effectiveness of various types of steel bracing (ISMB 450) i.e. X, V, inverted V, diagonal bracing are examined. Flat slab is also used by providing drop panels and peripheral beam. For all models parameters are kept constant. The effect of the distribution of the steel bracing along the flat slab to RC frame on the seismic performance of the building is studied. The performance of the building is evaluated in terms of storey displacement, storey shear, story drifts and slab stresses. The percentage reduction in lateral displacement along X direction is tabulated. As compared to V and diagonal braced frame, the inverted Vand X braced frame reduces the displacements and storey drift of the structure when combined with flat slab. The storey shear is significantly more for V and inverted V bracing. Providing the steel bracings and Flat slab with drop panels gives less slab stress on structure compared to RC bare frame. Hence it is concluded that the use of steel bracing with flat slab in construction resists the lateral forces for many vulnerable conditions.

Keywords: Steel Bracings, Flat Slab, Peripheral Beam, Drop Panel, Seismic Zone, Response Spectrum Analysis

DOI: https://doi.org/10.15623/ijret.2016.0508031