Flexural bearing capacity of lightweight concrete beams reinforced by end-hooked steel fibers

The application of lightweight aggregate concrete (LWAC) offers benefits such as reducing internal forces and self-weight in large-span bridges, making it a focal point in architectural advancements. Incorporating end-hooked steel fibers (end-hooked SF) significantly enhances the flexural performance and toughness of LWAC beams, effectively averting structural brittleness. However, the current calculation methods for LWAC beams do not consider the impact of fiber materials on load-bearing capacity post the addition of end-hooked SF. This study tested flexural load capacity on end-hooked SF lightweight concrete beams (end-hooked SF LWAC-beam). By adapting calculation approaches from the US, Canada, and Europe for steel fiber reinforced concrete beams, revisions were made to calculate the cracking load and ultimate load of LWAC beams, subsequently comparing and analyzing the results against experimental data. The integration of end-hooked SF resulted in a substantial improvement, with a 47.64 % increase in compressive strength and an 87.7 % increase in splitting tensile strength. Moreover, the cracking load and ultimate load exhibited enhancements of 94.05 % and 34.17 %, respectively. Notably, the mid-span deflection, average crack spacing, and maximum crack width displayed corresponding improvements due to end-hooked SF. After introducing the characteristic parameters of the end hook-shaped SF specified in the ACI, CSA and EC2 codes, the accuracy of the calculated values of the cracking moment and ultimate bending moment has been greatly improved, with an increase in the range of 22.39 %-24.34 %.This detailed analysis underscores that accounting for fiber characteristic parameters notably improves the accuracy of the cracking moment and ultimate moment calculations, aligning the results more closely with experimental data. Such considerations emphasize the necessity of incorporating fiber characteristics into the structural analysis of LWAC systems, providing a theoretical foundation for optimizing the bending performance assessment of LWAC beams.