Nonlinear Static Analysis-an Advanced Analytical Approach to Mitigate Seismic Risks of Overhead Circular Water Tank

Overhead water tanks are vital components of water distribution systems, subject to varying loads and environmental conditions that can impact their structural integrity. Traditional linear static analysis methods often provide limited insights into the true behavior of these tanks under extreme loading scenarios. Nonlinear static pushover analysis offers a comprehensive approach to the assessment of the structural response of overhead water tanks under large deformations and nonlinear material behavior. This paper delves into a detailed investigation of the application of nonlinear static pushover analysis techniques for evaluating the seismic performance of overhead circular water tanks. Key aspects of the methodology include the development of pushover curves to assess the tank's capacity and ductility, as well as the identification of potential failure mechanisms and critical regions prone to damage. The structural response is evaluated for the 200Cu.m. capacity tank through the force-displacement curve, hinge formation pattern, and period of the tank for variable staging heights of tanks 18m, 14m and 10m. The value of the base shear for the 14m staging height tank is around three times the 10m staging height tank and for the 18m staging tank, it is around eight times. From the pushover curve for 18m, 14m and 10m it can be observed that sufficient ductility is achieved. For all heights of the tank, it can be seen that there is no significant failure of the structural members of the tank. The variation of base shear values in pushover analysis for tanks with staging heights of 18m, 14m, and 10m shows that taller tanks generally experience higher base shears due to increased mass and dynamic effects associated with their height. The period of the tank reduces with a reduction in the height of the tank. From the formation of the hinges pattern, it can be seen that hinges are within immediate occupancy: IO to life safety: LS performance level and life safety to collapse prevention: CP level. The findings emphasize the importance of adopting a nonlinear static analysis advanced analytical approach to mitigate risks associated with seismic events and ensure the structural reliability of overhead water tanks in earthquake-prone regions.