Cracks have appeared in a section of segmental lining that had been reinforced with synthetic fibres on an extension of the Izmir Metro in Turkey. According to local news reports, the segments were reinforced with a combination of glass-fibre reinforced polymer (GFRP) and macro-synthetic fibres (MSF). The exact cause of the cracking is not yet known and is subject of an ongoing an investigation.
Although local news reports focused on the use of synthetic fibres, industry experts told TunnelTalk that cracking could have been caused by a range of factors. “It is likely that the segment was not properly designed,” said Ralf Winterberg, Group Chief Engineer of synthetic fibre manufacturer BarChip. “It is not the type of reinforcement but the design that is inadequate.”