International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 13 Issue: 02 | Feb 2026
p-ISSN: 2395-0072
www.irjet.net
A REVIEW OF LATERAL RESPONSE DIFFERENTIATION BETWEEN GEOMETRICALLY UNIFORM AND PLAN-DISTORTED REINFORCED CONCRETE BUILDING CONFIGURATIONS Ravi Kumar Gupta1, Mr. Ushendra Kumar2 1Master of Technology, Civil Engineering, Lucknow Institute of Technology, Lucknow, India 2Head of Department, Department of Civil Engineering, Lucknow Institute of Technology, Lucknow, India
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Abstract -Plan configuration plays a decisive role in
axial–flexural interaction, and torsion simultaneously, leading to complex stress redistribution within structural members. In seismic regions, inadequate lateral resistance has historically resulted in catastrophic failures, particularly in multi-storey moment-resisting frames lacking sufficient stiffness and ductility (Paulay and Priestley, 1992). The lateral response of RC buildings is strongly influenced by stiffness distribution, mass regularity, redundancy, and energy dissipation capacity. Modern performance-based seismic design frameworks emphasize drift control, ductility demand, and damage limitation, further underscoring the importance of understanding lateral load behaviour (Chopra, 2017).
governing the lateral load response of reinforced concrete (RC) buildings subjected to seismic and wind actions. While geometrically uniform configurations generally exhibit predictable stiffness distribution and stable modal characteristics, plan-distorted buildings—such as L-, T-, and U-shaped layouts—often develop torsional coupling, drift concentration, and irregular force redistribution. Despite extensive research on seismic irregularities, a consolidated synthesis comparing the lateral response characteristics of uniform and plan-distorted RC configurations remains fragmented. This review systematically examines experimental investigations, analytical formulations, and numerical simulations published over the past three decades to evaluate response differentiation between these configurations. Key response parameters considered include base shear demand, inter-storey drift ratio, torsional amplification, natural period variation, and plastic hinge formation patterns. The review identifies consistent trends indicating amplified torsional effects, localized damage concentration, and increased displacement demand in plan-distorted structures, particularly under nonlinear dynamic loading. Variations in findings are attributed to modelling assumptions, structural system type, and irregularity severity. The study further evaluates the treatment of plan irregularities in contemporary seismic design provisions and highlights critical research gaps. The synthesized insights aim to support improved performance-based design strategies and more rational assessment of irregular RC building configurations.
1.1.2 Increasing Architectural Complexity and Irregular Plan Configurations Contemporary architectural demands increasingly favour asymmetric and aesthetically complex layouts, leading to widespread adoption of irregular plan geometries. Functional requirements, site constraints, and urban density considerations often necessitate L-, T-, and U-shaped configurations. While architecturally appealing, such forms introduce non-uniform stiffness and mass distribution, which alter dynamic characteristics and modal participation factors. Empirical observations following past earthquakes have demonstrated that buildings with plan irregularities exhibit significantly different response patterns compared to regular configurations (Moehle, 2014). Consequently, the divergence between architectural form and structural regularity has become a critical concern in seismic design practice.
Key Words: Lateral response; Plan irregularity; Reinforced concrete buildings; Torsional amplification; Seismic performance; Nonlinear dynamic analysis
1.1.3 Seismic Vulnerability Associated with Plan Distortion
1. INTRODUCTION
Plan distortion induces eccentricity between the centre of mass and centre of rigidity, generating torsional response under lateral excitation. This torsional coupling amplifies displacement demands at peripheral elements, often resulting in localized damage concentration and premature yielding. Studies have shown that torsional irregularity can substantially increase inter-storey drift demands, particularly under nonlinear dynamic loading (Chandler and Duan, 1997). Post-earthquake reconnaissance reports, including observations from major seismic events such as
1.1 Background 1.1.1 Importance of Lateral Load Resistance in RC Buildings Reinforced concrete (RC) buildings are primarily designed to resist gravity loads; however, their performance during extreme lateral loading events such as earthquakes and strong winds governs structural safety and serviceability. Unlike gravity loads, lateral forces induce bending, shear,
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