Evaluation of inertia force and maximum midspan acceleration in steel fiber reinforced concrete beam at high-strain rates

Impact events, whether from vehicle collisions or terrorist attacks, present significant risks to infrastructure integrity, demanding a thorough understanding of dynamic responses. This study focuses on the impact loading dynamics of steel fiber-reinforced concrete (SFRC) beams, specifically emphasizing maximum acceleration and inertia force. Utilizing drop weight impact tests, dual accelerometers were used at midspan to capture acceleration history, while load cells at supports and on the impactor measured reaction and impact forces, respectively. The experimental approach adopted in this study investigated the influence of different masses, impactor heights, and span lengths on the initial kinetic energy and momentum. Additionally, a novel predictive model for determining the maximum midspan acceleration is proposed using regression analysis, accounting for material properties, geometry, and impactor characteristics. This model seeks to enhance accuracy across different impactors and beam attributes, spanning a wide strain rate spectrum. Through experimental validation, the efficiency of the proposed model is demonstrated in accurately predicting inertia force, making it applicable across various scenarios and strain rate regimes. • Maximum midspan acceleration and inertia force of SFRC under impact is discussed. • A new analytical model is proposed to predict max midspan acceleration. • Effects of impactor mass and height, elastic moduli, and span length are considered. • Inertia force is evaluated using three acceleration distributions along SFRC beam.