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Behaviour of Concrete under Biaxial Dynamic Loading



It is well known that both the compressive and tensile strength of concrete are rising with increasing strain rate. It is further known that a biaxial compression stress state also leads to a higher compressive strength. So the question arises: do these two effects superimpose in the case of a dynamic biaxial loading? This kind of load can arise in accidents like vehicle or airplane crash, rock fall or landslide on concrete structures. To investigate this topic, a biaxial Split-HOPKINSON-Bar (SHB) has been developed and constructed at the Technische Universität Dresden. With this new test setup cubic concrete specimens can be loaded with two compressive impulses perpendicular to each other with a time delay of less than 20 μs. First results have been achieved. These show that there is an interaction of the strength increasing effect because of the dynamic loading and that of biaxial state of stress. So the biaxial dynamic compressive strength of concrete is significant higher than the uniaxial dynamic strength and the biaxial static strength.

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