International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 07 | JUL 2025
p-ISSN: 2395-0072
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Seismic Behavior of Mid-Rise Structure under Varying Response Reduction Factors Harish Nutraganti1, Prof. Trupti Narkhede2, Prof. P. J. Salunke3 1PG student, Dept. of Structural Engineering, M.G.M college of Engineering, Maharashtra, India 2 Professor, Dept. of Structural Engineering, M.G.M college of Engineering, Maharashtra, India
3 HOD, Dept. of Structural Engineering, M.G.M college of Engineering, Maharashtra, India ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - This research paper investigates the effect of
design, the concept of ductility is embedded in the formulation of the response reduction factor (R), which modifies the design seismic forces based on the structural system’s expected energy dissipation capabilities.
varying structural ductility and response reduction factor (R) values on the seismic performance of a mid-rise reinforced concrete (RC) building. The response reduction factor accounts for the inherent energy-dissipating capacity of structural systems and directly influences the seismic forces considered in design. To explore this, a G+13 (14-storey) RC building was modeled and analyzed using the response spectrum method as per IS 1893 (Part 1): 2016, with different structural ductility configurations and corresponding Rvalues.
As per IS 1893 (Part 1): 2016, higher values of the response reduction factor are assigned to systems with superior ductile detailing, such as special moment-resisting frames and well-confined shear wall systems. Conversely, systems lacking proper ductile detailing are assigned lower R-values, resulting in higher design base shear and more conservative member design. The rationale is straightforward: structures with greater ductility can absorb more energy and are less likely to fail suddenly during ground motion, thereby justifying a reduction in seismic forces.
Four structural models were considered in this study: Model 1 representing a fully ductile structure, Model 2 with non-ductile beams and ductile shear walls, Model 3 with partial ductility (either beams or shear walls non-compliant), and Model 4 with both non-ductile beams and shear walls. The R-values applied for analysis were 5.0, 4.5, 4.0, and 3.0, respectively. Each model was evaluated based on key seismic performance parameters including storey displacement, storey drift, storey shear, and lateral load distribution. The results indicate that decreasing structural ductility and associated R-values lead to increased seismic demand in terms of base shear and member forces, while overall displacements and drifts are reduced. Fully ductile systems exhibit greater lateral flexibility but lower seismic forces due to higher energy dissipation, whereas non-ductile systems attract higher base shear but demand more reinforcement and stiffer sections. The study emphasizes the critical role of structural ductility in achieving an optimal balance between seismic safety and structural economy, especially in mid-rise RC buildings designed in high seismic zones.
F Figure 1: Fully ductile vs semi-ductile vs non-ductile frames. The conceptual diagram presented in Figure 1 highlights the contrasting behavior of structural systems under cyclic seismic loading. Ductile structures exhibit wide, stable hysteresis loops that represent significant energy absorption and residual strength after repeated load cycles. Non-ductile structures, on the other hand, display narrow, steep loops indicative of brittle failure, with little capacity to dissipate energy. Partially ductile configurations fall between these extremes, often showing reduced energy dissipation and early degradation in strength and stiffness. These visual differences directly correlate with the theoretical basis for varying R-values in design.
Key Words: Response reduction factor, storey displacement, storey drift, storey shear, lateral loads.
1.INTRODUCTION The seismic performance of reinforced concrete (RC) structures is largely influenced by their capacity to deform inelastically while maintaining structural integrity. This deformation capacity, known as ductility, allows structures to dissipate seismic energy through controlled cyclic behavior, reducing the forces transmitted to critical structural components. In modern earthquake-resistant
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