A stadium with 20.020 people capacity will be built in Debrecen, Hungary. The slab part of the precast, multi-stairs grandstand is only 12 cm thin and prestressed; PFRC is used instead of mild stirrups. Six types of polymer fibres were tested and compared according to RILEM regulations with the same dosage. Two selected types were tested with different amount of fibres between 0 and 10 kg/m3. The effect of increasing the amount of fibres was determined. 6 pieces of real size grandstand elements were made, 4 with selected fibres and 2 with stirrups calculated according to EC2. Bending and shear tests were made under laboratory conditions. A FEM model was built up, which corresponds to the real size tests. The minimum dosage of fibres was determined with the FEM model.