Investigating the blast resistance performance of reinforced concrete (RC) beams under explosive loads holds significant importance for structural safety engineering. As critical components of RC beams, stirrup configurations substantially affect their mechanical behavior. This study systematically examines how varying stirrup ratios affect blast resistance performance, aiming to establish quantitative relationships between stirrup ratios and dynamic responses and to identify performance-improvement saturation thresholds through integrated experimental explosion tests and finite element simulations. Two reinforced concrete beams with distinct stirrup ratios (0.64% and 0.37%, corresponding to 80 mm and 140 mm stirrup spacing, respectively) were designed and constructed. The specimens underwent four intensified blast scenarios (20 g, 40 g, 80 g air explosions, and 80 g contact detonation) within a controlled explosion chamber. Comprehensive dynamic response data of the beams were captured using accelerometers, strain gauges, and displacement sensors, while failure modes were meticulously documented. Subsequently, experimentally validated numerical models were developed in ANSYS/LS-DYNA finite element software, employing advanced fluid-structure interaction techniques for multi-material simulations. This study comprehensively evaluated the blast resistance performance of RC beams with five stirrup ratios (0.26%, 0.30%, 0.37%, 0.47%, 0.64%) and systematically compared their acceleration responses, strain distributions, mid-span displacements, and failure patterns. Experimental data demonstrated that under identical blast loads, Beam B₁ with 0.64% stirrup ratio showed 18%~22% reductions in peak acceleration, 25%~30% lower strain responses, and 35%~40% decreased mid-span displacements compared to Beam B₂(0.37% stirrup ratio), while maintaining superior structural integrity with 50% fewer diagonal shear cracks. Across all four blast scenarios, Beam B₁ demonstrated 9.4%, 10.0%, 11.6%, and 12.1% reductions in maximum mid-span displacement compared to Beam B₂. The failure analysis revealed that Beam B₂ developed substantially more cracks with severe blast-side concrete crushing and larger spallation areas, confirming that higher stirrup ratios effectively suppress diagonal crack formation and propagation while improving concrete damage resistance. Numerical simulation further confirmed a consistent inverse relationship between stirrup ratio (0.26%~0.64%) and structural response metrics, with progressive decreases in both peak concrete strain and mid-span displacement. Experimental data revealed significant performance improvements with increasing stirrup ratios:compared to the 0.26% reference beam, specimens with 0.30%, 0.37%, 0.47%, and 0.64% ratios demonstrated progressive reductions in peak strain (9.7%, 20.8%, 28.5%, and 35.4% respectively) and peak displacement (3.8%, 10.0%, 14.9%, and 18.2%). The study identified diminishing returns in dynamic response reduction-displacement improvements decreased from 10.0%(0.26%~0.37% ratio range) to 4.9%(0.37%~0.47%) and ultimately 3.3%(0.47%~0.64%), indicating a performance enhancement plateau beyond certain stirrup ratios. These findings provide critical quantitative guidelines for optimizing blast-resistant RC structural design in practical engineering applications.

Glass and basalt fibers have been extensively utilized in civil engineering applications, and their inclusion can enhance the mechanical properties of concrete materials. Empirical studies indicate that integrating fibers into reinforced concrete(RC) components augments their blast resistance. Specifically, at a volume incorporation rate of 0.2%, the efficacy of these fibers in enhancing the anti-explosion performance of concrete is notably pronounced. This investigation involves the design of standard concrete test blocks with a strength grade of C40, alongside glass fiber reinforced concrete(GFRC) and basalt fiber reinforced concrete(BFRC) test blocks, each with a volume incorporation rate of 0.2%. These specimens undergo compressive and split tensile strength tests to evaluate the influence of the respective fibers on concrete′s mechanical properties. The results demonstrate an improvement in the mechanical characteristics of both fiber-reinforced concretes. To assess the blast resistance of GFRC and BFRC beams, three types of beams-ordinary reinforced concrete(RC), GFRC, and BFRC-were constructed. Each beam was subjected to four explosive loads to observe the dynamic response and surface damage. The findings reveal that fiber reinforcement enhances concrete toughness and significantly mitigates the dynamic response of the beams under explosive loading conditions. Specifically, GFRC beams with a 0.2% volume fiber content exhibited lower peak accelerations and strains compared to BFRC beams, and the GFRC beams′ surfaces showed reduced spalling and crack formation relative to BFRC beams.