Upgraded Seismic Protection Strategy for AAC-Infilled RC Frames: Experimental Testing and Micro-Modelling

Abstract

Although Autoclaved Aerated Concrete (AAC) infills are widely utilized in modern construction, their brittle, non-ductile nature renders them highly vulnerable to structural failure during severe earthquakes. To resolve this structural vulnerability, this study establishes advanced, intensity-tailored seismic protection strategies for AAC-infilled reinforced concrete (RC) frames. The research methodology comprehensively integrates laboratory experimental testing of large-scale (1:2) bare and AAC-infilled RC frame models under concurrent vertical and horizontal cyclic or monotonic loading. These empirical data validate high-fidelity, nonlinear finite element micro-models, which are subsequently leveraged to execute extensive parametric studies evaluating structural performance under elevated axial loads not simulated during laboratory testing. The synthesized observations successfully quantify distinct damage patterns, crack distributions, and interactive failure mechanisms, demonstrating a critical necessity for systemic vulnerability reduction in high-seismicity regions. Consequently, a novel dual-tier protection framework is introduced: for high-seismicity zones subjected to strong earthquakes, a uniform multidirectional isolation system uniquely integrates base isolators with an original space flange energy dissipation (SF-ED) device, whereas for moderate-to-strong zones, an advanced design approach ensures safe, ductile frame-infill interaction. Ultimately, these findings establish a highly robust, validated strategic framework for effectively upgrading the seismic resilience of modern infilled frame configurations against severe structural damage.