Effects of Innovative Reinforced Concrete Slit Shaft Configuration on Seismic Performance of Elevated Water Tanks

Abstract

Elevated water tanks are considered crucial infrastructure due to their significant role in supporting essential services. A strong ground motion may result in a failure or significant damage to a reinforced concrete shaft of an elevated water tank because a formation of plastic hinges is limited to the base of the shaft, while the nonlinear properties of the rest of the shaft remain underutilised. A modification was made to a reinforced concrete shaft to enhance the seismic resistance of elevated water tanks by introducing slit zones at regular intervals that partitioned the shaft into four segments interconnected by foundation and short linked beams positioned at 5 m intervals. The slit zones were intended to increase the shaft's ductility, reduce stress concentration in the lower part of the shaft, and provide uniform stress distribution throughout the shaft's height. The comparative nonlinear dynamic study between several three-dimensional models of elevated water tanks with slit and solid reinforced concrete shafts was conducted using SAP2000 software. The research findings showed that during a seismic event, reinforced concrete shafts with slits significantly reduce seismic response values at the shaft's base of elevated water tanks with tall and slender shafts compared to short and broad shafts.