In-plane strength and stiffness of AAC floor without concrete topping in buildings with AAC masonry infill walls - experimental tests and numerical analyses

The diaphragm action of floors strongly influences the local and global seismic response of a masonry building. The American (ASCE 7-16) and European (EC8) Codes provide few and contrasting indications to classify the floor as 'rigid' or 'flexible'. Moreover, there is limited experience regarding the in-plane behaviour of diaphragms made of aerated autoclaved concrete (AAC) panels, and no specific regulations are available for AAC floors. The assessment of in-plane strength and stiffness of AAC floors without a concrete topping is still an open topic. In this work, in-plane diagonal compression tests on AAC precast panels without a collaborating slab are performed to evaluate the behaviour of AAC floors. Panels having a different thickness and depth of the shear key were considered for testing. The experimental results are then applied to two case study buildings to verify through numerical analyses if they behave as 'rigid' or 'flexible'. Numerical results showed an almost 'rigid' behaviour in terms of stiffness, but the in-plane strength is not always assured in conditions of marked irregularities of the building and high seismic-prone areas.