Design Provisions for Autoclaved Aerated Concrete (AAC) Structural Systems

The objective of this research program was to develop reliable design provisions for AAC structural systems. Typical AAC construction uses AAC shear walls combined with AAC floor or roof diaphragms. AAC shear walls are the predominant structural application of AAC. Because the behavior of AAC shear walls under combinations of reversed cyclic in-plane loading and gravity load is potentially complex, design provisions for AAC shear walls are of fundamental importance.

A comprehensive testing program was developed. The first phase of that testing program was intended to determine the behavior of AAC shear walls subjected to reversed cyclic lateral loads. Walls were made of a variety of AAC units, including masonry-type units and reinforced panels, laid either horizontally or vertically. The aspect ratio of the specimens (ratio of height to base length) varied from 0.6 to 3, and each specimen was designed to fail in either shear or flexure. Based on test results, procedures and corresponding design equations were developed to predict the behavior of AAC shear walls as governed by flexure, shear, and other limit states.

The second phase of the testing program involved the design, construction and testing, under reversed cyclic lateral loads, of a full-scale, two-story AAC assemblage specimen. Results from this second phase were used to validate the previously developed design provisions for shear walls, to evaluate proposed procedures for the design of AAC floor systems and connections, and to evaluate the overall behavior of AAC structures.

The mechanical properties of a material are fundamental to the design process for that material. Mechanical properties of AAC were determined at the Ferguson Structural Engineering Laboratory and validated with the results of material tests performed at other laboratories. Based on the results of those tests, design-related equations for material properties were developed for use in design provisions.

The combination of these three facets has resulted in comprehensive and reliable design provisions for typical AAC structural systems, verified through extensive testing.