Response of reinforced concrete beams subjected to debris impact: A simplified model

Recent research on progressive collapse has predominantly focused on redistributional mechanisms, where load paths are reestablished following the failure of critical members. However, many notable structural failures are governed by impact-type progressive collapse mechanisms, which remain less understood. To address this gap, this study develops a novel analytical model designed to study the dynamic interactions between impacting bodies and reinforced concrete (RC) beams. The model utilizes a mass-spring-damper system and introduces a dynamically recalculated equivalent mass. This advancement enables highly accurate predictions of contact forces, showing up improvements in accuracy compared to existing methods. A comprehensive parametric analysis was conducted, investigating the effects of critical variables such as the impactor's mass, velocity, and beam length. Among these, the velocity of the impactor was identified as the dominant factor that influences structural response, with significant implications for energy dissipation and failure progression. The results underscore the complex interplay between dynamic effects and structural properties, offering valuable insights into failure mechanisms under real-world impact conditions.