Behavior of reinforced concrete panels subject to impact by non-deformable projectiles.

摘要

In impact resistance of reinforced concrete (RC) panels against projectiles the contribution of the orthogonal mesh reinforcement has been ignored. In this study the contribution of mesh reinforcement to impact resistance and itseffect on the nature of local damage caused by impact of non-deformable projectiles are investigated. The investigation included a combination of 53 experiments and series of finite-element based numerical simulations. Three levels of local damage modes were investegated based on the severity of the degree of damage in the impacted panels. Mesh reinforcement ratio within the range of reinforcement ratio considered, namely 0.19% to 0.48%, was irrelevant to the impact behavior of RC panels under different impact velocities, while bar spacing was to be a controlling parameter for the degree of damage. RC panels reinforced with bar spacing greater than 1.5 times the panel thickness have a tendency to spall concrete from the back face more than RC panels with closely spaced bars. RC panels reinforced with bar spacing greater than 1.5 time the panel thickness formed punching shear crater, while panels reinforced with less than that limit distributed the damage over a wider area without forming the punching shear crater on the back face. Orthogonal mesh reinforcement with bars spaced no wider than one-third of the projectile diameter were able to prevent the projectiles from perforating the panels. Offseting the reinforcing meshes did not improve the impact resistance of RC panels. An equation was developed to estimate the perforation resistance of an RC panel under impact of non- deformable projectile with given mass, diameter, and impact velocity.