ABSTRACT
In order to utilize the benefits of steel fiber reinforcement and ensure an economic design at the same time, a new approach to produce hybrid lining segments was developed and is presented. The basic principle is to strengthen the vulnerable zones of segments with a high performance steel fiber reinforced concrete (HPSFRC), while for less critical zones an ordinary lining concrete is used. Focusing on the longitudinal joints, an experimental study on the bearing and fracture behavior of hybrid specimens, produced with a so called “wet-on-wet” production procedure, has been conducted under concentrated load. It was proven that the installation of a HPSFRC layer only in zones where critical splitting stresses occur leads to a remarkable increase in the bearable loads. The results showed that the use of vertical instead of horizontal formworks had a positive impact on the fiber orientation and thus consequently on the bearing behavior.
