Copyright © 2026 Authors retain the copyright of this article. This article is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

@article{207481,
        author = {Sanket vijay wadekar and Girish joshi},
        title = {Response-Spectrum Sensitivity of an Irregular High-Rise RCC Building to IS 1893 Soil Classes: An ETABS-Based Comparative Study},
        journal = {International Journal of Innovative Research in Technology},
        year = {2026},
        volume = {13},
        number = {3},
        pages = {1285-1294},
        issn = {2349-6002},
        url = {https://ijirt.org/article?manuscript=207481},
        abstract = {This study quantifies the sensitivity of an irregular reinforced cement concrete (RCC) high-rise building to the hard, medium, and soft-soil design spectra specified by IS 1893 (Part 1): 2016. A common three-dimensional ETABS v22 model, approximately 108.1 m high, was analysed by the response-spectrum method while the structural geometry, mass source, member assignments, and loading model were retained. The evaluated outputs were maximum story displacement, story drift, story shear, equivalent-static base shear, response-spectrum base reaction, diaphragm displacement, and the maximum-to-average displacement ratio used to screen torsional irregularity. The design horizontal coefficients were 0.010667, 0.014507, and 0.017813 for hard, medium, and soft soil, respectively. The corresponding equivalent-static base shears were 3290.65, 4475.29, and 5495.39 kN. Independent back-calculation from Vb/Ah produced a consistent seismic weight of approximately 308.50 MN for all three cases, supporting mass-source consistency. Relative to hard soil, the soft-soil spectrum increased maximum story displacement from 36.065 to 70.296 mm (+94.91%), maximum story drift from 0.000417 to 0.000811 (+94.48%), and maximum story shear from 3393.38 to 5495.39 kN (+61.94%). The largest directional drift was 0.000862 in the Y direction, only 21.55% of the IS 1893 limit of 0.004. Conversely, the Y-direction torsional ratios (1.235–1.267) exceeded the 1.2 irregularity threshold for every soil spectrum, demonstrating that plan asymmetry remained a governing configuration issue even when drift compliance was achieved. The study distinguishes soil-spectrum sensitivity from direct soil–structure interaction (SSI): no continuum soil domain or calibrated foundation impedance is evidenced in the available model documentation. The results therefore support preliminary design screening and spectrum selection, while advanced SSI analysis is recommended for site-specific foundation response.},
        keywords = {RCC high-rise building; response spectrum; soil class; IS 1893:2016; ETABS; story drift; base shear; torsional irregularity},
        month = {August},
        }