Evaluation of Response Reduction Factor of an Elevated Water Tank Using Pushover Analysis for Different Soil Types

Abstract

Earthquake ground motions are one of the most dangerous natural hazards due to which there is heavy economic and life
loss. Most of the losses are due to collapse of buildings, bridges, liquid retaining structures etc. Elevated water tanks are vital
structures in water supply systems. Their protection presentation is an important task during strong earthquakes. Response
reduction factor (‘R’ factor) is defined as the factor by which the actual base shear force should be reduced to obtain the
design lateral force. In the present work, efforts are made to calculate the ‘R’ factor for elevated overhead water tank of 12m
staging height and having different soil types (20m3
, 30m3
, 40m3
, 50m3
and 70m3
). The influence of soil types, time period and
seismic zones on response reduction factor are studied. With the help of ETABS13 software, displacement controlled non-linear
pushover analysis is carried out to evaluate the base shear and ductility factor of water tank. It is observed that the value of
Response reduction factor is affected by seismic zones, soil type, and ductility of tank, time period and capacity of the water tank.