Evaluation of Exterior Wall Behavior Using Reinforced Autoclaved Aerated Concrete as Cladding

The objectives of this study were to evaluate the capacity of thin-autoclaved aerated concrete (AAC) panels used as an external cladding system using either timber or cold-formed steel framing as a backup system and develop predictive models. Both out-of-plane and in-plane loads were applied to wall segments. Out-of-plane pressure testing was completed on 12 wall specimens using a vacuum test setup to load the walls. The primary variable was the type of backup system, wood or cold-formed steel. Strong correlation was achieved for pressure specimens based on applying one-way slab theory using tested mechanical properties and flexural cracking. Leeward winds were simulated by flipping the specimen. Suction tests that failed at the fastener locations were effectively modeled based on direct shear and tested material properties. A total of four light-frame, AAC-sheathed shear wall specimens were built and tested under in-plane, monotonic-racking loads. In all cases, damage was initiated by cracking or crushing at the fastener-AAC interface. Following the completion of the shear wall testing suite, a model based on elastic fastener forces was applied and is proposed as an analysis tool for AAC-sheathed shear walls. Experimental test results were compared with the model with ratios of observed to predicted capacities ranging from 1.14–1.33, indicating conservative results.