Robustness of RC building structures with infill masonry walls: Tests on a purpose-built structure

Structural robustness is a significant property towards improving resilience of buildings, i.e. enhance their ability to withstand and recover from extreme events which often can cause local damage and progressive collapse. It is widely accepted that robustness depends on the capacity of the structure to activate alternative load paths (ALPs) after the failure of load-bearing elements, e.g. columns. Early evidence during World War II showed that progressive collapse of some buildings was avoided by the presence of masonry infill walls. Subsequent studies focused on this effect for cases of sudden column removal although most of these studies were analytical, numerical and only looked at internal columns which are generally less vulnerable to accidental events compared to corner and edge columns. The aim of this study was to analyse how infill walls can improve the robustness of reinforced concrete (RC) buildings in corner columns failure scenarios. A purpose-built 3D two-storey full-scale RC building structure with infill masonry walls was tested. The contribution of masonry infill walls was analysed in terms of: (i) load redistribution, (ii) ALPs, and (iii) Dynamic Amplification Factors (DAFs) to be applied in linear-static analyses. The test was highly monitored by 38 strain gauges, 38 LVDTs and 2 accelerometers to register the vertical and lateral response. The results showed that masonry infill walls had a significant influence on the structural response and activated the predominant ALPs at very small deflections.