Volume 18, No. 6, 2021
Seismic Analysis Of Reinforced Concrete Buildings In Hilly Topography
Chandak Narayan R. , Vaidya Onkar , Agrawal Achal
Abstract
The behaviour of a building during earthquakes depends critically on its overall shape, size, geometry and Building site, in addition to how the earthquake forces are carried to the ground. Hence, at the planning stage itself, architects and structural engineers must work together to ensure that the unfavorable features are avoided and a good building configuration & site condition is chosen. In some parts of world, hilly area is more prone to seismic activity; e.g. northeast region of India. Most of the northern hilly region of India lies in the seismically active belt of the Himalayan range. Three major earthquakes (M>8) Kangra (1905), Bihar-Nepal (1934) and Assam (1950) have occurred in this hilly track during the last century and it may repeat. Analysis and comparative study of buildings on sloping ground considering seismic forces with different seismic zones III & zone IV is carried in this paper. The software used for the analysis in present study is SAP 2000v14.0 Advanced. In the present study, 56 RC buildings with different no. of storey ranging from 4 to 10 storey (13.5m to 31.5m height) resting on sloping ground and plane ground are considered for linear static & dynamic analysis. The work has been divided into two phase and each phase consists of four groups of buildings and in each group, 7 numbers of buildings are considered. In 1st group, buildings are resting on plane ground & in 2nd, 3rd, and 4th group, buildings are resting on sloping ground with angle of slope 23 degree, 27 degree & 31 degrees respectively. In first phase, all 28 numbers of buildings have been analyzed under seismic zone III & in second phase, same 28 numbers of buildings have been analyzed under seismic zone IV. The buildings with equal number of storey have same geometric properties and floor area in both phases. The height and length of buildings in a particular pattern are in multiple of blocks (in vertical & horizontal direction), the size of block is being maintained at 5m x 4m x 3m. The depth of footing below ground level is taken as 1.5m where the hard stratum is available. It is concluded that the performance of buildings on sloping ground during seismic excitation could prove more vulnerable than the building on plane ground. There is increase in the value of shear force as the height of building (No. of Storey) increases by Equivalent Static Analysis (ESA) and Response Spectrum Analysis (RSA) along the slope & across the slope direction.
Pages: 9259-9269
Keywords: Seismic analysis, Sloping ground, Equivalent Static Analysis (ESA), Response Spectrum Analysis (RSA).