Journal of Korean Tunnelling and Underground Space Association ISSN:2233-8292(Print) 2287-4747(Online) 한국터널지하공간학회 논문집

In this study, a series of fire experiments under HCinc and ISO834 (duration of 4 hour) fire scenarios were carried out for three different types of fire protection measures for the segment joint to evaluate their applicabilities to an immersed tunnel. The experimental results revealed that an expansion joint installed to allow relative movements between concrete element ends in an segment joint is the most vulnerable to a severe fire. For the fire protection measure where the originally designed steel plates at an expansion joint are replaced by fire-resistant boards, the experiments showed that they cannot achieve good fireproofing performance under both HCinc fire scenario and ISO834 (4 hour) fire scenarios since the installation of fire-resistant boards results in the reduction of the sprayed fire insulation thickness. On the other hand, the application of modified bent steel plates replacing the original steel plates was proved to be very successful in fireproofing of the expansion joint due to more sprayed materials filled in bent steel plate than in the original design concept as well as higher adhesion between the steel plate and the sprayed fire insulation layer.