Description of the spatial variability of concrete via composite random field and failure analysis of chimney

The inherent variability of concrete significantly affects the structural safety and performance. The variability of concrete is a complex phenomenon influenced by multiple factors, including material properties, production processes, and environmental conditions. Understanding and quantifying the variability of concrete is crucial for reliable and safe structural design. Probabilistic methods are commonly used to account for concrete variability in structural design. In this paper, a composite random field approach combined with a hierarchy model is used to consider the multi-scale spatial variability of concrete. The random field of compressive strength is expressed as a sum of independent component random fields. To investigate the impact of concrete's spatial variability on structural response and failure modes, the failure analysis of a 115-m-tall chimney was conducted. The results indicate that the composite random field approach proves to be a valuable method for incorporating concrete's spatial variability at different scales. The spatial variability of concrete exerts a substantial influence on the potential positions where severe compressive damage might occur. Additionally, the failure modes are also affected by the spatial variability of concrete. When taking into account the spatial variability of concrete, an extra collapse mode emerges, aligning more closely with the chimney's actual collapse mode during an earthquake. Furthermore, the spatial variability of concrete also moderately impacts the variability of the base shear force and the maximum inter-section drift angle. Notably, improper approaches to considering the spatial variability of concrete significantly impact the concrete's compressive damage and structural response.