Use of FRP Reinforcement constructing diaphragm pit walls

FRP is an anisotropic composite material with a high tensile strength in axial direction and a high resistance against corrosion. The anisotropy of the material is quite advantageous at excavation pits for the starting and finishing processes at automated excavation like tunnel boring machine (TBM) and Pipe jacking. Concepts of design and their economical advantages are demonstrated by means of projects. For the first time in Germany the FRP reinforcement has been used at diaphragm pit walls at the construction of the metro line stations "Brandenburger Tor" and the North-South-Line in Cologne. Based on the derived design method the final design of the diaphragm pit walls was carried out and the successful functionality was checked during construction phase.