Seismic analysis of structure with inclined column at base and floating column at first story

The following findings were derived from the seismic study of multi-story reinforced concrete buildings in Zones II, III, and IV that had floating and inclined columns. The comparison result between basic and oblique column models is summarized below. ●         Inclined column systems reduce base shear by about 11.9%–28.9%, roof displacement by 41.6%–62.3%, and overturning moment by 14.85%–25.5% compared to vertical columns. They also show lower time periods (2.3%–18.6%), indicating improved stiffness and overall seismic performance, making them more efficient for taller buildings in higher seismic zones. ●         In the G+10 building located in Seismic Zone 2, the base shear was observed to increase by 4.79% in the FCC model, 2.74% in the NCC model, and a significant 201% in the CW model, when compared to the base model. For the G+15 structure, the base shear exhibited a reduction of 8.57% in the FCC model and 7.44% in the NCC model, while the CW model showed an increase of 132.1%. Similarly, in the G+20 configuration, the base shear further decreased by 33.37% in the FCC model and 13.83% in the NCC model, whereas the CW model experienced an increase of 58.17%. ●         A similar comparison was carried out for buildings located in Seismic Zones 3 and 4. The maximum increase in base shear was found as 201.4% in the G+10 CW model. The G+15 FCC model in Zone 3 demonstrated superior performance compared to other configurations. ●         In Zone 2, the G+10 structure exhibited an increase in roof displacement by 39.59% in the FCC model and 41% in the NCC model, while a reduction of 31.16% was observed in the CW model. For the G+15 structure, displacement increased by 64.3% in FCC, 58.47% in NCC, and decreased by 50.76% in CW. Similarly, the G+20 configuration showed increases of 121% and 41.16% in FCC and NCC respectively, with a 34.46% decrease in CW. ●         A similar comparison was carried out for buildings located in Seismic Zones 3 and 4. Maximum increased in displacement was 91.4% % in FCC and minimum decreased was 43% in G+20 CW model. The G+20 CW model in zone 3 performs well compare to other model. ●         In Zone 2, the G+10 building exhibited an increase in stiffness by 12.4% in the FCC model, 5% in the NCC model, and a substantial 910.15% in the CW model. For the G+15 configuration, stiffness increased by 1% in FCC, decreased by 6.55% in NCC, and significantly increased by 687.19% in CW. In the G+20 building, stiffness decreased by 58.28% in FCC and 28.92% in NCC, whereas the CW model showed an increase of 182.75%. ●         In Zone 3& 4, similar trends were noted. The G+10 CW model showed maximum stiffness of 854.9% in Zone 3. Overall, the CW model consistently demonstrated a significant improvement in stiffness across all zones and building heights when compared to FCC and NCC models. ●         In Zone 2, the G+10 building exhibited an increase in overturning moment by 11.98% in the FCC model, 11.89% in the NCC model, and 13.67% in the CW model. For the G+15 configuration, the overturning moment increased by 8.15% in FCC, 8.05% in NCC, and 8.27% in CW. In the G+20 building, overturning moment decreased by 4.33% in FCC, increased slightly by 0.73% in NCC, and decreased by 2.77% in the CW model. ●         A similar comparison was carried out for Zones 3 and 4. In the G+10 building, maximum overturning moment increased by 16.41% in CW in Zone 3. overturning moments varied across zones and building heights, with CW models generally exhibiting higher values in Zone 2 and 3, while Zone 4 demonstrated reductions in G+10 models, suggesting improved overturning resistance.

1.                    Aleti Ganesh et al(2023) “Evaluation of Response Spectrum and Equivalent Static Analysis for recognizing the safest position of Floating Columns by ETABS in Zone V” International Conference on Computational Intelligence and Sustainable Engineering Solutions (CISES)DOI: 10.1109/CISES54857.2022.9844329 2.                    B.C. Pumia, Ashok Kumar Jain, Arun Kumar Jain, Professor and Head, Department of Civil Engineering M.B.M Engineering College, Director, Arihant Consultants, Assistant Professor M.B.M Engineering College” Design of Steel Structures (Second Revision) 1998”. 3.                    IS1893:2016 “Criteria of Earthquake Resistant Design of Structures (Sixth Revision), bureau of Indian Standards, Manak bhavan, 9 bahadur shah zafar Marg new delhi”. 4.                    IS800:2007 “General Construction in Steel” Code of Practice, (Third Revision) Bureau of Indian Standards, Manak bhavan, 9 bahadur shah zafar Marg new delhi. 5.                    IS875(part3) “Wind load on Buildings and StructuresCode of Practice, (Third Revision) Bureau of Indian Standards, Manak bhavan, 9 bahadur shah zafar Marg new delhi. 6.                    IS456:2000, “Plain and Reinforced Concrete Code of Practice”Bureau of Indian Standards. 7.                    Mr. Purvesh & Dr. Pujari “Review on Effect of Slanted Column in Building”international journal of progressive research in engineering management and science (IJPREMS),Vol 3,Issue 01, January 2023, pp : 38-41,DOI: https://www.doi.org/10.58257/IJPREMS30562 8.                    Mohammed Zameer Ahamed J(2022), "Seismic Analysis of High-Rise Structure Considering the Effect of Floating Columns", International Journal of ScientificResearch in Science and Technology(IJSRST), OnlineISSN : 2395-602X, Print ISSN : 2395-6011, Volume 9Issue 4, pp. 388-398, July-August 2022. doi :https://doi.org/10.32628/IJSRST229461 9.                    Neha Pawar et al (2021) “Review on Effect of Floating Columns on Buildings Subjected to Seismic Forces” IOP Conf. Series: Earth and Environmental Science 822(2021)012045doi:10.1088/1755-1315/822/1/012045 10.                 Navaneeth Krishna1 & Abhishek (2020) “Seismic Behaviour of Multistorey Building with Oblique Column and Its Height Optimization” International Research Journal of Engineering and Technology (IRJET) ,Volume: 07 Issue: 07 | July 2020