Low Velocity Impact Response of Reinforced Concrete Flat Slabs

Dimensions of the reference concrete slab are 1950x1950x100 mm subjected to drop-weight impact loading.

A comprehensive parametric study was performed to examine the influence of many parameters on the RC slabs.

From the viewpoint of cost and time savings, a three-dimensional finite element is a very good tool to predict the real behavior of the structural elements.

Results showed that the use of CFRP strips enhance the impact behavior of the slab. Contrarily, the existence of opening led to a dramatic decrease in the dynamic capacity of RC slabs with stress concentration around the openings. Furthermore, changing the shape of the impactor showed a significant effect on the peak impact load as well as the ultimate deflection at impact instant.

In the scope of this paper, the response of RC slab with top and bottom reinforcements exposed to drop-weight impact loading was inspected. Time histories of impact loads and deflections were presented in detail based on ABAQUS/ Explicit analysis. The findings presented in this paper can be presented as follows:

1. The FE models show a good correlation with the experimental data. Consequently, the proposed finite element models are efficient and economical tool to explorer the effect of many parameters on the performance of RC slabs subjected to drop-weight impact load.

2. The numerical simulation confirmed that using externally bonded CFRP strips has more influence on the peak deflection of the reinforced concrete slab than the recorded impact force.

3. Comparing to the flat shape of the impactor, the hemispherical and curved shape impactor can produce large penetration depth at the impact zone with higher plastic deformations in the concrete slab. However, the flat impactor produced higher deflection at the impact instant.

4. As the radius of the impactor increases, both the duration time and the peak impact force are increased. This is because of the higher contact area was obtained when the flat impactor (infinity radius of curvature) was used as compared to other impactors.

5. Due to decreases in RC slab stiffness, the presence of openings (regardless of their shape) has considerably increased deformations in concrete especially around perimeter of the openings extended to the nearby support.

6. It has been found that the eccentric impact loading causes higher plastic deformations than the concentric one.