Full-Field Deformation Measurement and Debonding Analysis in Masonry-Infilled RC Frames Under Lateral Loading

Abstract

This study investigates the in-plane lateral behavior of reinforced concrete (RC) frames with masonry infill walls, addressing their critical yet frequently overlooked role in seismic design. Four half-scale specimens, two bare frames and two with double-leaf masonry infills, were subjected to lateral cyclic and monotonic loading. High-resolution Digital Image Correlation (DIC) was utilized to precisely monitor strain, displacement, and interface slip. Results show that infills significantly increase maximum lateral strength (2.6-2.7 times) and initial stiffness (4.4-5.3 times) compared to bare frames, but reduce displacement ductility and exacerbate stiffness degradation. Crucially, DIC revealed that initial gaps from construction sequencing trigger early interface debonding at roughly 75% of peak load, initiating a diagonal strut mechanism that imposes severe shear demands on beam-column joints. This research uniquely links local construction practice to structural resilience and validates DIC as an advanced diagnostic tool for mapping complex frame-wall interactions.