Tragverhalten von Flachdecken aus Stahlfaserbeton im negativen Momentenbereich und Bemessungsmodell für das Gesamtsystem

Bearing Capacity of Steel Fiber Reinforced Concrete (SFRC) Flat Slabs in the Negative Bending Moment Area and Design Model for the Complete System

The present paper deals with the bearing behaviour of steel fibre reinforced concrete (SFRC) flat slabs in the negative bending moment area. Tensile forces are carried only by steel fibers. The latter allow, due to a dosage of 100 kg/m³ (1.3% in volume), a high rotation capacity with simultaneously high bearing capacities. In a first step experimental analysis showed that under symmetrical loading no punching shear failure occurred. A bending behaviour with creation of yield lines was observed for all test specimens. Furthermore, a decreasing fibre orientation with growing plate height could be noticed. The effect of openings in the column area on the bearing capacity loss in a local failure were evaluated with the use of non-linear finite element software. Scatter in bending tensile strengths was used to calculate a safety factor by the means of a semi-probabilistic safety concept. Eventually, slab design is performed by using yield line theory.