A Comparative Experiment Study on Precast Tunnel Segments

Increasing popularity of using fibres in concrete has brought questions about their usability in segmental tunnel linings as an alternative to the conventional lining. Prior studies have already revealed that the replacement of conventional steel reinforcement is possible with steel fibres. However, the usability of macro-synthetic fibres (MSFs) as reinforcements in precast tunnel segments is still unclear and one of the controversial questions to be answered. This study aims to evaluate the structural applicability of using MSFs in precast tunnel segments by means of an experimental program on full-scale specimens. Fourteen full-scale precast tunnel segments of four different reinforcement cases were analysed: typical conventional steel reinforcement; combination of MSFs and conventional reinforcement; combination of MSFs and glass fibre reinforced polymer rebars (GFRP); MSFs only. Flexural tests were carried out to compare the flexural capacities of specimens at the service limit state, while point load tests were conducted to observe the structural performance of precast tunnel segments under the effect of design thrust forces. The experimental results showed that combination of MSFs and GFRP could be an innovative solution for precast tunnel segments in case of using a suitable quantity that satisfied the project requirements