Bilfinger Berger AG completed construction of the 4.5 km Chungho subway line in Taipei, Taiwan ready for operation. The project included building four subway stations, three emergency exit shafts, tunnels with a diameter of 5.6m excavated using tunnel boring machines, tracks laid on strip foundations, and electrical, communications, and ventilation systems installed. The stations were built with diaphragm walls up to 55m deep used as retaining walls during the cut-and-cover construction method. The Chungho Line opened to traffic six months ahead of schedule after USD 695.6 million was spent on construction from 1992 to 1998.

1. Bilfinger Berger AG comple-
ted the 4.5-km Chungho
subway line in Taiwan's capi-
tal city, Taipei, ready for ope-
ration.
In addition to constructing the
tunnel tubes, the project
included building four subway
stations, three emergency-exit
shafts, laying the tracks and
installing the line's electrome-
chanical equipment.
The twin-track stretch runs
through separate tubes with a
diameter of 5.6 m. Tunnelling
operations involved three
tunnel-boring machines. The
tunnels were lined with inner
shells consisting of segmen-
tal rings 0.25 m thick.
The stations were built using
the cut-and-cover method.
Diaphragm walls up to 55 m
deep and as much as 1.2 m
thick, with overlapping hori-
zontal reinforcement were
used as retaining walls. Since
they could not be anchored,
they had to be braced by
multiple layers of steel girders.
All stations were designed to
allow further development
above. Foundation piles 1.5
m in diameter were drilled in
order to accommodate the
resulting additional loads. In
some places, the relevant
end bearing layers were only
encountered in depths of 80
m.
Building the subway line
ready for operation also inclu-
ded installing all its electrical,
communications, fire-
protection, ventilation and
sanitary equipment, as well as
elevators and escalators, in
addition to laying the tracks.
The tracks were laid on strip
foundations. Standard 18-m
rails were welded into 180 m
long sections that were carted
to their place of installation
and bolted onto preassem-
bled mounting brackets riding
on elastomer buffers. AItoge-
ther, 12 km of track and
eighteen switches had to be
laid.
The interiors of the stations
were finished to a high stan-
dard. Areas open to the ge-
neral public and equipment
rooms are air-conditioned.
AItogether 25 escalators and
twelve passenger elevators
were installed.
The Chungho Line was ope-
ned to traffic six months
ahead of schedule.
n Contract Value:
USD (m) 695.6
n Construction Period:
06/1992 - 12/1998
n Client:
Taipei City Government,
Department of Rapid
Transit Systems
n Services:
Construction of a
subway line ready
for operation
Reg.14-BB-605-19.6.818-00-A
ChunghoChunghoChunghoChungho Line,Line,Line,Line,
Taipei, TaiwanTaipei, TaiwanTaipei, TaiwanTaipei, Taiwan