Investigation of Concrete Slabs under Impact Load

Abstract:

The behaviour of concrete slabs under dynamic load such as rock fall or vehicle impact isinvestigated in this work. The aim of this study is to enlarge the knowledge concerning thesubsequent reinforcing of concrete slabs and its inuence on their behaviour under impact load.Therefore, the results of the drop tower experiments with standard concrete, high performanceconcrete (HPC) and ultra-high performance concrete (UHPC) are compared and interpreted.The analysis of the test results focuses on the qualitative evaluation of the protective e ectand on the quantitative evaluation of measurement results. Regarding the protective e ect, theinuence of the additional steel stirrup reinforcement is rather small. In contrast, the subsequentfabric reinforcement prevents the perforation of the concrete slabs. The behaviour of steel fabricand carbon fabric is compared. Although particular di erences in fracture behaviour are seen,both types of fabric reinforcement obviate total punch-through and, hence, vastly enhance theprotective performance. Comparing the stamping cones and analysing the extent of damage, theprotective capacity of di erent concrete slabs is evaluated. Within the quantitative evaluationof the measurement results, the evolution of strains and strain rates is being considered. Onthe top side of the concrete slabs, the strain is measured as tensile strain in the rst spellafter load application, turning into compressive strain later on. The evolution of strains andstrain rates indicates wave propagation. Beside the strain results, special attention is paid tothe correlation of di erent measurement techniques. The results of strain gauges, accelerometer,load cells and photogrammetry are contextualised and therefore show the change from the localmaterial behaviour to the global structure response in temporal sequence.