Experimental and numerical evaluation of fibre-reinforced concrete vault forming slabs subjected to low-velocity impact loading

Vaults and dome structures are attractive in architecture due to their ability to evenly distribute weight and support substantial loads without internal columns. Fibre-reinforced concrete is ideal for these compressive structures, which experience low tensile stress. Assessing their performance under impact loading is crucial for safety, financial protection, and preserving cultural heritage. In this study, twelve arch-shaped slabs with thicknesses of 50, 75, and 100 mm, incorporating varying fibre percentages, were tested using a drop-weight impact test machine. Finite element analysis, validated against experimental results, was employed to evaluate the slabs' behaviour under low-velocity impacts. The analysis revealed multiple flexural cracks in fibre-reinforced specimens, with maximum crack widths decreasing as fibre ratios increased. Although the number of microcracks rose with higher fibre content, crack spacing diminished. Results indicated that adding steel fibres significantly enhances tensile strength and energy absorption-showing a 90% increase in the 100 mm thick dome with 1.5% fibres-while reducing cracking. These improvements contribute to the durability, stability, and safety of concrete domes, lowering maintenance costs. Thus, incorporating steel fibres in the design and construction of impact-resistant concrete domes is highly recommended.