Dynamic response and sectional forces of reinforced concrete frames subjected to impact loads

The dynamic response of reinforced concrete (RC) frames to accidental impacts remains an active subject, which is of paramount importance for ensuring the safety and integrity of civil structures. In this paper, an experimental investigation is presented to analyse the dynamic response of RC frames with varying clear spans and sectional dimensions under multiple impacts. To further explore the influence of boundary conditions on structural response, two additional beams with different boundary constraints were also tested for comparison. The test results demonstrated that an increase in the drop height led to wider cracks and more concrete damage, which translated into larger peak and residual displacements, and enhanced energy absorption capacity. The beam section played a significant role in the impact force. The frame structure exhibited higher impact force, minor damage of concrete and lower displacement response of beam compared to the simply-supported beam, indicating the effective restraint provided by frame columns to frame beams enables the frame structure. Sectional forces can be accurately traced through the application of Digital Image Correlation (DIC). The distributions of bending moment and shear force were accurately measured to evaluate the dynamic mechanical performance. The bending moment and shear force interaction diagrams for critical sections were constructed and analysed to gain a deeper understanding of the failure mechanisms under impact. • Multiple drop-weight impact tests on RC frames have been conducted. • Effects of different research parameters on dynamic response of RC frames are revealed. • Dynamic cross-sectional force diagrams have been derived using DIC technology.