Ultra high performance concrete (UHPC) is characterized especially by high compressive strength up to 250 N/mm ² as well as high impermeability and resistance to corrosion. These properties come along with increasing brittleness. Brittle concretes have lower scaled strength under multiaxial load compared to ductile normal strength concrete. The effective application of UHPC requires specific knowledge of load bearing behaviour under multiaxial stress conditions. This paper describes the behaviour of UHPC under biaxial compressive load in comparison to normal strength concrete. It will show that the calculation approach for DIN is not transferable to UHPC. Furthermore a model will be suggested to realistically describe the load bearing behaviour of UHPC for instance in FE models.