Tunnels are an essential part of the road and rail infrastructure, making it possible to connect goods and services and help economic regions grow. For this reason, it is important to protect tunnels against the extreme heat that occurs during a tunnel fire. To investigate whether tunnels can withstand these extreme temperatures and whether the tunnel can be repaired after a fire, Efectis developed the Mobifire. The Mobifire® performs small-scale in-situ tests in existing tunnels and helps tunnel owners design corrective measures to protect the concrete support structure.

This spring, Efectis Nederland performed a series of tests in the Michiel de Ruyter Tunnel near Amsterdam Central train station. This road tunnel crosses the subway line and the bus station at the back of the train station. We conducted tests both to investigate concrete behaviour and to assess what protective system would meet the required 132 minutes exposure to the RWS fire curve that reaches up to 1350 degrees Celsius. For each test we inserted nine thermocouples into the concrete surface. An insulating board was placed against the tunnel wall or roof to simulate a protective system. After the installation of the board the mobile furnace (Mobifire) was carefully put in place. The test ran either for the required 132 minutes or until spalling of the concrete started.

The advantages of testing with the Mobifire are:

  • The ability to test in existing buildings
  • Testing the actual situation (pressure, weather influences, etc.)
  • Damage can be repaired after a test (non-destructive)

 

Contact: Jos Bienefelt – [jos.bienefelt@efectis.com]

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