Seismic Analysis and FRP Jacketing of 4-storey RC Building

Abstract

In the recent past, India has seen mass destruction due to failure of structures hit by earthquakes and consequently, lost a lot of lives. Hence, it is of utmost importance that attention be given to the evaluation of the adequacy of strength in framed RC structures to resist strong ground motions. In this project, a 50-year old four storey reinforced concrete structure has been considered, which lies in Zone II according to IS 1893:2000 classification of seismic zones in India. For non-structural members masonry infill has been assumed. In the Equivalent Static Method of analysis, the seismic load acting on the structure is assumed to be an equivalent static horizontal force applied to individual frames. The total force applied shall be equal to the product of the acceleration response spectrum and the seismic weight. It is used only for low to high rise buildings without significant coupled lateral-torsional modes. The structure is designed in STAAD.Pro v8i, considering M15 concrete and Fe250 steel reinforcement for with and without earthquake loading conditions. The demand moments and shear have been noted down from the software analysis and compared to the capacities of the given section. FRP jacketing is the most appropriate method of retrofitting the failing members in the given 4-storey RC structure. The norms stated in ACI 440-2R.02 have been followed to calculate and suggest the method and scheme of application of FRPs to the member and also the number of plies to be used. Thereafter, an analysis has been done on the amount of efficiency achieved in dealing with the deficiency in the members. The FRP strengthening system has been checked for serviceability as well as creep-rupture limits since the entire modelling, analysis and design for the structure has been done using limit state design.