Experimental and numerical investigations of UHPFRC beams under impact loading

The impact performance of ultra-high-performance fiber-reinforced concrete (UHPFRC) beams under impact loading is studied experimentally and numerically in this research. Ten UHPFRC beams were fabricated for the test to examine the effects of impact energy and reinforcement configuration on the cracking patterns and dynamic response of UHPFRC beams. According to the test results, all specimens exhibited flexural-brittle failure. The characteristic values of impulse, impact duration, maximum displacement, residual displacement, and absorbed energy all increased gradually with the impact energy. The longitudinal reinforcement ratio decreased, the maximum width and height of the bending main crack gradually increased. The specimen equipped with double-layer tensile longitudinal bars could better limit the development of cracks in the specimen. The effect of stirrups ratio on dynamic response of UHPFRC beams was limited. Finite element software ABAQUS was used to simulate the impact test, and the accuracy of the simulation was verified with the test results. The effects of various parameters on the dynamic responses of UHPFRC beams were further investigated through parametric studies. Genetic algorithms were utilized to predict the parameter values of UHPFRC beams under the most unfavorable impact resistance state. These findings inform structural and strengthening design for UHPFRC beams under impact loading.