Bemessungsansatz fuer Tunnelschalen aus Stahlfaserbeto

摘要

Due to its properties to follow bending deformations breakless and to resist high normal force stresses at the same time steel fibre reinforced concrete is fundamentally suitable as a building material for tunnel shells. If the relocation of bending moments obtained by cracking and strengthened activation of the bedding is to be used computationally, the plastic rotations necessary for this are to be proved. The present essay shows how the results at the Ruhr-University Bochum of accomplished experimental examinations with eccentrically stressed steel fibre reinforced concrete beams for a design calculation of steel fibre reinforced concrete and the proof of the rotational capacity for tunnel shells can be used. The qualitative comparison of mat reinforced shotcrete and tunnel shells consisting of steel fibre reinforced concrete shows in the latter one a homogeneous structure, fewer defects in form of spraying shades, a better bond between individual shotcrete layers and alltogether a higher load-carrying capacity and water impermeability. The quantitative comparison of computationally determind M-K-lines makes clear that the moment capacity depends on the amount of the acting normal force. Steel fibre reinforced concrete can exhibit a higher moment capacity with-larger utilisation rates of the pressure normal force in opposite to mat reinforced shotcrete. Further it was shown that larger cross section curvatures are reached with steel fibre reinforced concrete. Related to the entire load-bearing structure, bigger rotation angles can be adjusted in cracked areas and therefore stronger redistributions of moments can be achieved.