Comparative Study on Seismic Load Resistance of Multi-Story Building Resting on Flat Ground and Varying Slope Ground

Abstract

It is usually common that buildings were founded on levelled grounds. However, there are a number of circumstances when this might be impossible or not preferred due to various factors in construction activities where buildings are getting constructed on uneven grounds of varied slopes. This change in the level or formation of foundation is proposed to have effect on the various responses of the buildings to external and internal stresses and forces. This work analyzes effects on three main seismic responses viz. story displacement, story drift and base shear of G+5, G+8 and G+11 story building resting on varied sloped with angles of 10 degree, 15 degree and 20 degree in comparison to the responses of the buildings resting on flat ground. Modeling of the buildings and analysis of seismic responses were performed by using ETABS 2018.00. The results of each seismic variable of the building resting on varying sloped ground with the defined number of stories were presented compared to their corresponding buildings resting on flat ground. Accordingly, for G+5 building story displacement on sloped ground has decreased with maximum of 36.64% and base shear has decreased by 15.23% compared to the flat ground.. For G+8 building, story displacement has decreased by 17.87% and base shear has increased by 16.66% compared to the flat ground. For G+11 building, story displacement has decreased by maximum of 17.13% and base shear has increased by maximum of 16.38% compared to the flat ground. Story drift on sloped grounds of all the buildings considered in tis work has randomly become above and below that of flat ground without any specific pattern in decrement and/or increment. Generally, the analysis results indicate that sloped grounds have higher seismic resistance than flat grounds in case of top story displacement. As the ground slope increases, top story displacement has been decreased in all cases considered under this study. However, the maximum base shear effects of sloped grounds were observed to be higher than that of flat ground. The third variable, story drift of the two lower slopes (10 and 15 degree) were found to be higher than that of flat ground; whereas, the higher slope had lesser drift effect compared to flat ground.