Seismic Performance of Reinforced Concrete Buildings on Hill Slopes: A Review

The primary constructions on hill slopes of India's seismically active Himalayan regions are sloping ground buildings. Based on rapid visual screening, many of these towns have vulnerable built stock, inherently irregular in geometry, owing to both plan and vertical irregularities imposed by slopes. The current paper presents a comprehensive review of the classification of sloping ground buildings, their source of irregularity, parameters influencing seismic response, irregularity and storey damage descriptors, and vulnerability methods to quantify their seismic performance. Finally, different seismic retrofit strategies for their improved seismic performance are also presented. Six principal typologies prevalent in practice are identified in sloping ground buildings. Irregular geometry, storey ratio, slope angle, and type of foundation soil are the most prominent influencing parameters of seismic performance. Among these typologies, step-back buildings are more vulnerable than split-foundation and step-back setback buildings. These buildings' upper street-level columns attract more shear forces during seismic shaking than the lower street-level columns, leading to brittle catastrophic failure. Different vertical irregularity descriptors, storey damage descriptors, and vulnerability assessment methods are available for generic RC buildings. However, the applicability of these descriptors and vulnerability methods needs to be verified in the case of sloping ground buildings. Nature of structural modeling (2D vs 3D frames) and consideration of soil–structure effects can be critical in seismic modeling and analysis of such typologies. Methods such as earthing tie beams, RC walls, RC-filled steel tubular columns, and strengthening ground-storey columns have been suggested to improve the performance of these buildings. © 2023, The Institution of Engineers (India).