Structural degradation assessment of a preheater tower in a cement plant in Peru

This article examines the structural behavior of a paradigmatic case in the cement industry: an existing reinforced concrete (RC) Preheater Tower (PT). The study focuses on assessing the degradation caused by the severe operational conditions of these industrial facilities and evaluating the consequent impact on structural safety. PTs are defined by their considerable total and inter-platform heights, substantial live loads on all platforms and prolonged exposure to high temperatures from the clinker preheating process. These factors pose significant structural challenges in ensuring long-term safety. Unlike previous studies, this research provides a more comprehensive analysis by investigating scenarios that are likely to occur throughout the lifecycle of critical industrial structures like PTs. Through in situ non-destructive dynamic tests conducted on all platforms and detailed finite element (FE) modeling, a rigorous calibration process was carried out to match observed vibration frequencies at different levels. The obtained parameters were then compared with the mechanical properties of concrete after long-term exposure to elevated temperatures. The analysis reveals that PTs in the cement industry undergo significant degradation due to prolonged exposure to medium and high temperatures. This concern is particularly critical in high-seismic-risk zones and in cases where inadequate maintenance results in the loss of necessary thermal insulation in cyclones and ducts—especially the platform over the kiln, which is the most vulnerable to high temperature exposure. Overall, this study establishes a reliable methodology for evaluating PTs safety by integrating on-site vibration analysis, FE structural modeling, and predictive modeling for PT under frequent seismic events.