ABSTRACT
In the present 2003/2004 revised German standard for shotcrete, technical rules and design methods for strengthing purposes are provided that are compatible with the most recent harmonized European standards on concrete and reinforced concrete. In this paper, simple rules for the design of strengthening using shotcrete are described. The typical material variations through the depth of a shotcreted layer are the key to explaining and understanding the excellent adhesion and the distribution of stress in the old concrete structure and in the new reinforcement and shotcreted layer applied for strengthening. The variations in material properties in the shotcrete are predicted by determination of those mix proportions which are actually realized in the shotcrete as placed due to rebound effects. At present, no structural design methods are available in standards covering steel fibre reinforcement or textile glass fibre reinforcing techniques.
