Dynamic behaviour of ultra-high performance concrete beams with rectangular openings subjected to impact loads

To facilitate residents' needs, contemporary building structures often incorporate prefabricated transverse openings in reinforced concrete (RC) beams to accommodate pipeline installations. However, these openings can potentially impact the load-bearing capacity of the beams, particularly as structures increasingly need to consider dynamic loading effects. The use of ultra-high performance concrete (UHPC) has proven effective in enhancing the dynamic resistance of RC beams with openings. This study employs numerical simulations in ANSYS/LSDYNA to investigate the dynamic response of UHPC beams with rectangular openings exposed to low-velocity impact. The calibrated Continuous Surface Cap (CSC) model is primarily validated through quasi-static fourpoint loading tests on UHPC beams with openings. Following this validation, numerical simulations of drop hammer impact are carried out to comprehensively analyse the behaviour of UHPC beams with openings. Furthermore, parametric investigations are performed to evaluate the impact response of UHPC beams with large or small openings, considering various design factors such as opening size, opening position, stirrup quantity and UHPC strength level.