شکست ورقه بتن آرمه تحت بارگذاری ضربه ای
Abstract
1- Introduction
2- Analytical model
3- Experiments of projectile perforation of thick concrete and reinforced concretes slabs
4- Results and discussions
5- Conclusion
References
Abstract
A failure analytical model was developed to assess the characteristics of reinforced concrete slabs under oblique perforation by a rigid projectile in three stages: initial cratering, tunneling and shear plugging. The energy dissipation for the initial cratering and tunneling was obtained by integrating the axial resistance force along the penetration direction, and for shear plugging using a new method considering the reinforcement. Analytical expressions for the failure characteristics of reinforced concrete slabs were obtained using energy methods. Projectile perforation experiments were conducted for thick concrete and reinforced concretes slabs and the damage size was measured. The theoretical predictions closely agreed with the experimental results and a parametric analysis of the slab failure characteristics were also discussed.
Introduction
Concrete and reinforced concrete have been widely used in various defense and civil engineering fields for anti-impact protection of structures, such as bridges, dams, and nuclear power plants, against high dynamic impact loading [1–3]. Hence, understanding the failure characteristics of a reinforced concrete slab under such impact loading is crucial [4,5]. For example, several concrete fragments that will cause serious secondary damage to the facilities inside the protective structure will be generated on the rear face of a reinforced concrete slab when a high-speed projectile perforates it [6–9]. Therefore, research into projectile penetration or perforation of high-value buildings and structures has been receiving considerable attention. Extensive experimental research on projectile penetration and perforation of a concrete slab has been conducted over the last century, and several penetration and perforation empirical formulas have been obtained [10,11], such as the widely used Petry, ACE, Barr (UKAEA), and NDRC formulas. Although many experiments have been concerned with the penetration of reinforced concrete slabs, the effect of reinforcing bars has been incorporated only in some formulas, such as the Petry, Barr (UKAEA), and Boswell formulas [12].