Publication

Abstract : It is prudent to build critical buildings (such as hospitals, power grids, and fire stations) on flat competent ground. Nevertheless, in hilly terrain, such buildings are built on hill slopes resulting in the height of the building changing along the slope (Fig 1). Therefore, it is essential to develop floor acceleration spectra (FAS) for such buildings to aid the seismic design of acceleration sensitive non-structural elements. This study considers reinforced concrete buildings with special moment frame to assess the applicability of code recommended equations to estimate peak floor acceleration (PFA) for the design of non-structural elements. The study buildings are designed conforming to the existing Indian seismic design standard. Subsequently, FAS and PFA for the said buildings are estimated using Linear and Nonlinear Time History Analyses (LTHA and NTHA) using 20 natural earthquake ground motions. Also, quantified in this study is the effect of unreinforced masonry infill walls on the FAS and PFA. Results of NTHA indicate that the FAS and PFA vary within a given floor-the PFA near the flexible frame is about 30-50% more than the same near the stiff frame. This difference is due to the twisting of the building while resisting ground motions perpendicular to the slope along which it is built. Further, comparison between models with and without infill indicates the said difference is less by about 10% for buildings in which unreinforced masonry infills are present. Finally, a comparison is presented of the results obtained with those recommended in seismic design codes-the code recommended amplification is found to be adequate for low-rise reinforced concrete buildings on slope.