Seismic Performance Assessment of G+12 Foam Concrete Reinforced Concrete Frames Using ETABS: A Comparative Study with Normal Weight Concrete

Aniket Sahu^*1, Mrs. Ankita Singhai^*2, Dr. Rahul Kumar Satbhaiya^*3

*¹Research Scholar, Civil Department, Infinity Management & Engineering College, Sagar.

*²Asst. Prof. and Guide, Civil Department, Infinity Management & Engineering College, Sagar.

^*3 HOD, Civil Department, Infinity Management & Engineering College, Sagar

Abstract: The seismic vulnerability of reinforced concrete (RC) structures is closely tied to their self-weight, as inertial forces during ground shaking scale directly with structural mass. Structural Lightweight Concrete (SLWC), produced using foam concrete incorporating fly ash and quarry dust, presents a viable strategy to reduce dead loads and thereby attenuate earthquake-induced forces. This study presents a comprehensive comparative seismic performance assessment of a G+12 RC frame structure designed with foam concrete (LWC) against an equivalent normal weight concrete (NWC) bare frame. Structural modeling and analysis were carried out using ETABS software in accordance with Indian Standard IS 1893 (Part 1): 2002. The foam concrete mix comprised 65% fly ash, 35% cement, and 1.5% preformed protein-based foam by total weight, with quarry dust incrementally added up to 30% to enhance compressive strength. Seismic response parameters evaluated include maximum bending moment, shear force, storey displacement, storey drift, and axial force at each floor level under equivalent static and dynamic loading. Results reveal that the LWC frame exhibits a 22.81% reduction in maximum bending moment (from 734.17 kN-m to 566.81 kN-m) and a 10.77% reduction in shear force (from 941.85 kN to 840.43 kN) relative to the NWC bare frame. Maximum storey displacement also decreased from 88.84 mm to 66.16 mm, confirming markedly superior lateral stiffness. Additionally, the LWC alternative achieved a 18.78% reduction in concrete material costs and a 23.20% reduction in reinforcement requirements. These findings affirm that foam concrete is a structurally efficient and economically attractive material for earthquake-resistant high-rise construction in moderate-to-high seismic zones of India.

Keywords: foam concrete; lightweight reinforced concrete; seismic analysis; ETABS; IS 1893; storey displacement; bending moment reduction