Structural and dynamic properties of elevated water tanks for better performance during earthquakes

ABSTRACT

This research deals with the study of the various factors affecting the performance of circular shaped elevated water tanks made of reinforced concrete material with framed staging with filled as well as empty conditions due to past Indian earthquakes. Six ground accelerations have been picked out based on the strong motion parameters. Eight numbers of existing tanks have been selected with different storage capacity and structural configurations. Seismic performances such as base shear, base moment and hydrodynamic pressure are calculated using Response Spectrum method for the ground accelerations selected. The results due to all the ground accelerations are compared with that obtained by the elastic design response spectrum available in IS1893: part1 (2016). Eventually, it has been found out that the performances of each tank for every acceleration is highly influenced by the structural configuration, mainly for empty tanks. Hence, this research is intended to achieve desirable performances of water tanks during the occurrences of earthquakes by providing appropriate number of columns and horizontal bracing configuration. To ensure this, an experimental investigation has also been done on two models, tank 1 of capacity 105.86 m³ and tank 2 of 223.278 m³, to determine the dynamic properties of tanks.

Keywords:
Lateral stiffness; Natural time period; Base shear; Hydrodynamic pressure; Ground accelerations