Full‐Scale Experimental Evaluation of the In‐Plane Seismic Interaction Between Drywall Partitions and Two‐Story Reinforced Concrete Building: Mitigating Structural Vulnerabilities Through Polymer‐Based Isolation

ABSTRACT

Although drywall partitions are generally regarded as non‐structural elements, they interact with the primary structural frame and can significantly influence the structural response during seismic events. This study presents a full‐scale experimental investigation to quantify this seismic interaction and validate a novel polymer‐based isolation strategy, denoted as SISPYL. Two identical full‐scale, two‐story reinforced concrete buildings were subjected to quasi‐static cyclic loading. One building featured standard rigid drywall partitions, while the other incorporated the isolation system, replacing specific sections of the rigid gypsum core with a deformable polyurethane polymer at both perimeter and connection interfaces. The standard rigid installation exhibited an initial lateral stiffness of 20.93 kN/mm. This rigid composite action triggered a dominant membrane behaviour, transferring severe localised shear forces to the structural connections. This induced a premature soft‐story mechanism at the ground level, culminating in widespread structural and non‐structural failure before a roof drift ratio of 1.62%. Conversely, the deformation decoupling achieved by the SISPYL system reduced the initial lateral stiffness by 32.4% (to 14.15 kN/mm) compared to the standard configuration. This isolation prevented the transfer of damaging membrane forces, mitigated shear damage in the reinforced concrete joints, and restored a uniform story drift distribution. Consequently, the isolated frame accommodated lateral deformations up to a roof drift ratio of 2.39% while developing its intended distributed flexural yielding. Finally, the isolated configuration exhibited a stable equivalent viscous damping ratio between 5% and 6%, aligning the structural response more closely with code design assumptions for non‐interacting infills.