Optimal calculation of reinforcement in tunnel segmental lining

The capability of steel fiber-reinforced concrete to carry tensile stresses, also in the presence of wide cracks, allows designers to reduce the area of steel reinforcing bars. This aspect has been taken into account in a new design procedure of concrete segmental linings, capable of computing the behavior of ordinary reinforced cross-sections subjected to bending moment and normal forces. Accordingly, a practical formula to quantify the possible reduction of steel rebars in fiber-reinforced concrete is proposed in the present paper. This formula, which is in accordance with code rule requirements, has been used to optimize the reinforcement of prefabricated concrete linings.