Determining equivalent tensile Strengths of Steel-Fibre Shotcrete
Through the application of steel-fibre shotcrete (SFRS) initial supporting in an unsecured area is possible in the case of many tunnel projects. Nowadays a permanent inner shell made of SFRS is being called for more and more frequently. Dimensioning takes place through determining the equivalent tensile strength as is explained in the following contribution.
For temporary (outer) tunnel shells the construction method using steel fibre shotcrete (SFRS) is state of the art and facilitates an initial support without undertaking work in the unsecured area.
Usually dimensioning is carried out without any formal static analysis of equivalence to conventional solutions (e.g. matting reinforcement) using a minimum amount of effort.
Increasingly however permanent inner shells are being produced at present in international tunnelling providing suitable geotechnical marginal conditions exist (e.g. low water pressures) made of SFRS  while renouncing...