Seismic Analysis Of Elevated Water Tank With Different Bracing Soil Condition Using ETABS

A circular reinforced-concrete elevated water tank (10 m diameter, 15 m wall height, M30/Fe500) was evaluated in ETABS for three staging configurations — unbraced, single diagonal bracing, and double X-bracing — under soft-soil response-spectrum loading. The unbraced configuration develops a maximum displacement of 1.824 mm, drift of 0.000267, and storey shear of 464.66 kN, forming the baseline for comparison. Double X-bracing emerges as the most structurally effective configuration among those evaluated, reducing displacement by 74.98% and drift by 85.39%, at the cost of an 11.00% increase in storey shear. Single diagonal bracing improves drift control but increases global displacement, and its ETABS model requires targeted verification of brace orientation, end releases, and load-combination assignment before use in final design. Shell-level resultants — membrane force, shear, and bending — decrease consistently with increasing bracing redundancy, confirming that the benefits of bracing extend from the staging system into the container shell itself. Among the configurations studied, double X-bracing is identified as the optimum staging arrangement for this tank geometry and soft-soil condition, balancing deformation control against a manageable increase in force demand. A supplementary soil-sensitivity assessment indicates that displacement and drift are expected to reduce further, while storey shear increases, as soil stiffness increases from soft to hard soil — a trend consistent across all three bracing types, though based on assumed rather than verified values. From a sustainability and lifecycle perspective, the substantial drift reduction achievable with double bracing lowers the likelihood of structural distress, cracking, and consequent water loss or repair-related expenditure over the service life of the tank, supporting more resource-efficient long-term performance of water-supply infrastructure.

[1] Sangeetha, S. et al., "Seismic analysis and design of elevated water tank with comprehensive soil-structure interaction assessment," IRJET, vol. 11, no. 3, 2024. [2] Naeem, M. and Ganesh, G., "Seismic analysis of double-decker elevated water tank," Int. J. Res. Trends Multidiscip. Res., 2025. [3] Rimal, H. et al., "Seismic fragility of aging elevated water tank with smooth bars considering soil-structure interaction," Buildings, vol. 13, no. 1, p. 4, 2023. [4] Borkar, R. V. et al., "Seismic analysis of elevated water tank by using various types of bracing and staging pattern," Int. J. Manage. Technol. Eng., vol. 8, no. 6, 2018. [5] Dubey, R. et al., "Seismic analysis of underground water tank considering soil structure interaction," Int. J. Eng. Res. Appl., vol. 11, no. 10, pp. 21–25, 2021. [6] Sagar, S. and Kamal, S., "Seismic performance of elevated reinforced concrete water tanks," 2021. [7] Jayadeep, K. S. et al., "A study on the seismic response of elevated water tank," IRJET, vol. 9, no. 3, 2022. [8] Bahale, V., "Seismic analysis of elevated steel water tank with or without base isolation," Int. J. Creative Res. Thoughts, vol. 10, no. 10, 2022. [9] Gholap, N. S., "Nonlinear time history analysis of an elevated water tank," Int. J. Adv. Res. Sci. Commun. Technol., 2020. [10] Bureau of Indian Standards, Criteria for Earthquake Resistant Design of Structures, Part 2: Liquid Retaining Tanks (IS 1893 Part 2:2014, incl. Amendment No. 1), BIS, 2014.