*Article* **Blast Resistance of Reinforced Concrete Slabs Based on Residual Load-Bearing Capacity**

**Lijun Wang 1, Shuai Cheng 2, Zhen Liao 2, Wenjun Yin 2, Kai Liu 2, Long Ma 2, Tao Wang 1,\* and Dezhi Zhang 2,\***

<sup>1</sup> School of Nuclear Engineering, Rocket Force University of Engineering, Xi'an 710024, China

<sup>2</sup> Northwest Institute of Nuclear Technology, Xi'an 710024, China

**\*** Correspondence: wtao009@163.com (T.W.); zhangdezhi@nint.ac.cn (D.Z.)

**Abstract:** In this paper, the blast-loading experiment and numerical simulation are carried out for RC slabs with two typical reinforcement ratios. The time history of reflected shockwave pressures and displacement responses at different positions on the impact surface of the specimens are obtained, and the influence of the reinforcement ratio on the dynamic responses and failure modes of the RC slabs is analyzed. Based on the experimental data, the simulation model of the RC slab is verified, and the results indicate good agreement between the two methods. On this basis, the residual load-bearing capacity of the damaged RC slabs is analyzed. The results show that the load distribution on the impact surface of the slab is extremely uneven under close-in blast loading. The resistance curve shape of the RC slabs varies markedly before and after blast loading, and its load bearing capacity and bending stiffness deteriorate irreversibly. Increasing the reinforcement ratio can impede crack extension, reduce the slab's residual displacement, and, at the same time, reduce the decrease of the damaged slab's load-bearing capacity. The findings of this study will provide insights into the anti-explosion design and damage evaluation of RC slabs.

**Keywords:** reinforced concrete slab; blast loading; residual load-bearing capacity; dynamic response; blast resistance
