Out-of-Plane Performance of Lightweight AAC Infills within RC Frames Using Noncontact Full-Field Strain Measurement Technique

Abstract

The present research aimed at investigating the out-of-plane (OOP) behavior of autoclaved aerated concrete (AAC) block masonry to further advance their application as structural infills considering different parameters (slenderness ratios, central window opening, and loading conditions) using a noncontact optical full-field strain measuring method. The fundamental behavior of AAC blocks and masonry assemblages were also assessed under different loads (compression, shear, and flexure) and verified with the design requirements. The development of arch-resisting mechanisms, OOP deformation profiles, cracking patterns, and damage mechanisms were assessed. Comprehensive comparative analysis was conducted to examine the OOP behavior of AAC block infilled frames with similarly constructed solid clay brick masonry infills. Further, an effort was made to review the requirements of the available design provisions and empirical models to envisage the OOP load and deformation capacities of AAC block masonry infills. The experimental investigation determined that lower slenderness ratio (15.1) specimens attained higher OOP load-bearing capacity (>3.5 times) and energy consumption (>2.1 times) compared with slender specimens (30.2). The presence of a window opening (11.3% area ratio) and repeated loading did not reveal significant reductions in OOP load (<15%) and deformation (0.83–0.94 times) capacities compared with the monotonic loading counterpart. The OOP arch-resisting mechanism vanished (capacity dropped to 20%–40% peak), and the failure was sudden due to the disintegration of the cross section and OOP fall-out of damaged components, demonstrating the OOP vulnerability of AAC infill. Crack widths and OOP deformation after vertical splitting cracks formation were precisely apprehended using the full-field strain measuring digital image correlation technique.