Investigations
into safeguards against vehicle fires in immersed tunnels
Osamu
KIYOMIYA1,
Hiromitsu IIDA2, Takaya TAKIMOTO2
1. Waseda University; 2. Nippon Civic Consulting Engineers
Co., Ltd.
Tunnels and Underground, Vol.31, No.4, 2000.
Key words: immersed tunnel, vehicle fire,
fire resistance, fireproof, model test, design specification,
FEM analysis
Background
Fires within tunnels can cause many
deaths and injuries and result in closure of the tunnel for
months. Road and railway tunnels therefore require measures
to safeguard against fire accidents. Germany and Holland have
adopted standards for fire resistance for tunnel design, but
most other countries, including Japan, have no design criteria
for fire resistance and simply minimize the risk of tunnel
fire by forbidding vehicles carrying dangerous goods from
entering tunnels. Most immersed tunnels are constructed for
traffic access in coastal areas of cities. Consequently, traffic
using them makes a disproportionately high contribution to
the national and city economy. It is therefore more rational
to design such tunnels to be fire resistant rather than to
restrict access to them.
Research Summary
The authors first reviewed the practices
and concepts behind fire resistant design for immersed tunnel
linings abroad. We then investigated performance requirements
for Japanese construction conditions, fireproof materials
for tunnel linings, and possible design specifications for
fire resistance. In investigating possible design specifications,
we conducted full scale model fire tests of the joints of
immersed tunnels (full sandwich construction) and compared
the test results with the results of numerical analysis using
the finite element method (FEM). The research was practically
oriented and we have also now combined fireproofing into the
structural design of linings for actual immersed tunnels.
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