Kuala Lumpur’s Stormwater Management and Road Tunnel (SMART) is
a unique solution to the Malaysian capital’s long-term traffic and
stormwater management problems and the first tunnel of its kind in
the world. The dual-purpose tunnel diverts floodwaters away from
the confluence of the two major rivers running through the city
centre while its central section doubles up as a two-deck motorway
to relieve traffic congestion at the main southern gateway into the
city centre.
Tunnel segments being lifted into onto the
delivery trainSMART was originally conceived as a flood
relief tunnel to divert the 1 in 100 year flood away from the city
centre. Then it was also realised that the 11.8m internal diameter
tunnel could be utilised in periods of low rainfall as a highway
tunnel to alleviate Kuala Lumpur’s congested highway
infrastructure.
Mott MacDonald was approached by the MMC Engineering Group-Gamuda
JV to carry out the feasibility study for this innovative dual
purpose tunnel and then provide detailed design services to take
the project from concept through to construction, working in
association with SSP Consultants. The SMART project was completed
under the supervision of Mott MacDonald/SSP on behalf of the joint
venture.
The SMART Tunnel is a single innovative solution to
recurring floods and congestion in Kuala Lumpur Project
Highlights
The overall £335 million scheme comprises 9.5km of tunnel with the
central 3km incorporating a double deck motorway. Major components
include an upstream intake structure, holding pond and storage
reservoir, diversion tunnel, twin box culvert and ingress/egress
connectors to the motorway tunnel. Ventilation of the road tunnel
requires construction of four 15m-high shaft structures.
SMART works on a three mode system. Mode one operates under normal
conditions or when rainfall is low such that no water needs to be
diverted into the tunnel. Moderate storms activate mode two. This
will divert floodwater into a bypass tunnel in the lower section of
the motorway tunnel which will remain open to traffic. During the
once or twice yearly heavy storms a switch is made to mode three
when the tunnel is closed to road traffic. The tunnel section is
then utilised to create a combined capacity of 3 million cubic
metres in addition to the water bypass sections to divert the
dramatically increased flows. Extensive monitoring stations will
ensure sufficient time is allocated to allow the last vehicle to
exit before the automated watertight gates are opened. The motorway
will then reopen to traffic after cleaning of the tunnel within 48
hours of closure. Measures have been taken to ensure that the
change-over between modes from vehicle to flood use is practical
and efficient.
Cross-section illustrating the SMART dual pupose
tunnel design Ground conditions dictated construction by
tunnel boring machine, which was completed with two slurry TBMs
working in opposite directions from the middle of the tunnel
alignment. We helped develop the TBM procurement strategy and
produce contract documents to enable the contractor to purchase two
13.2m diameter machines – among the world’s largest in diameter. A
ventilation shaft sited near central Kuala Lumpur served as the
launch site for the TBMs. The ventilation facilities are located in
Limestone rock, with the largest excavation being 150m in length,
20m wide and 28m deep.
The 13.2m TBM cutterheadThe first TBM
launching shaft was completed in January 2004 ready for assembly of
the first TBM which commenced tunnel boring in June 2004. Shortly
after this the second TBM arrived for assembly and commissioning
and began tunnelling in August 2004. The highway section was opened
to the public on 14th May 2007 and the by-pass was made available
to route flood flows from July 2007.
Project recieves international acclaim at BCI Awards 2008
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