Saturday, October 2, 2010

SMART Tunnel

im interested to share with you what i whatched in MAJALAH 3 yesterday (saturday, 2nd OCT '10) about SMART Tunnel....

Order year 2003
Construction started 2004 (tunnelling)
Project type Stormwater tunnel with integrated dual-decked motorway tunnel
Location Kuala Lumpur, Malaysia
Estimated investment US$510m
Completion End of first quarter 2007
Sponsors Government of Malaysia
Full specifications - In 2003, construction began on the Stormwater Management and Road Tunnel (SMART) project – the longest and most technologically advanced tunnel in Malaysia. The 13.2m diameter tunnel consists of a 9.7km stormwater bypass tunnel, with a 4km dual-deck motorway within the stormwater tunnel. The main purpose of SMART is to solve the problem of flash flooding in Kuala Lumpur from the Sungai Klang and Kerayong rivers and also to reduce traffic jams during the daily rush hour. The motorway is suitable for light vehicles only. SMART opened to traffic on 14 May 2007. The cost of the project was around MYR1,887m (approximately $514m). The project was commissioned by the Government of Malaysia. The tunnel handles 30,000 cars per day and has been used 44 times to divert floodwater.
The SMART tunnel begins at Kampung Berembang lake and ends at Taman Desa lake. The tunnel diverts floodwaters away from the confluence of the two major rivers that run through the centre of Kuala Lumpur. The risk of the city being flooded has been estimated to be once every 100 years

The SMART tunnel works on a three-mode system:
First mode (Normal conditions)
The first mode, under normal conditions where there is no storm, no flood water will be diverted into the system.
Second mode (Most storms)
When the second mode is activated, flood water is diverted into the bypass tunnel in the lower channel of the motorway tunnel. The motorway section is still open to traffic at this stage.
Third mode (Major storms)
When this mode is in operation, the motorway will be closed to all traffic. After making sure all vehicles have exited the motorway, automated water-tight gates will be opened to allow flood waters to pass through. The motorway will be reopened to traffic within 48 hours of closure

Kuala Lumpur sits on karstic limestone with a high ground water table. For this kind of geology it was decided that tunnel boring machines (TBMs) would be the most cost-effective and least damaging method to the most cost-effective and least damaging method to construct the tunnel.
After much research, two 13.2m diameter Slurry Shield TBMs were chosen. In terms of diameter, these are among the world’s largest. The Slurry Shield TBM consists of four main parts:

Rotary Head Cutter, with tungsten pick bits used for excavation of soil and disc cutters used for the excavation of rock Bulkhead, where a pressured bentonite slurry shield is formed to provide stability during the tunnel excavation Hydraulic Rams, which were used to drive the machine forward and keep the tunnel in its correct position Tunnel Lining Erector, used to install the pre-cast concrete wall lining
In addition to the above, the TBM featured two bogies on rails that house electrical, slurry pumping, ventilation equipment and cables/pipes.
Both Slurry Shield machines started from the JKR field area in Jalan Chan Sow Lin. One machine bored northwards, under Jalan Tun Razak and Jalan Desa Pandan and ended at the lake at Ampang, behind Gleneagles Hotel. The other TBM bored southwards, under the Jalan Chan Sow Lin and the KL-Seremban Highway alongside the Sg Besi airfield and terminated at the lake in Taman Desa. Tunnelling began in 2004 and was completed in August 2006.

There are ventilation/escape shafts at 1km intervals throughout the tunnel. These will constantly renew the air and maintain the air quality within the motorway section of the tunnel.
To protect the ventilation system during flooding, the systems consist of a series of shafts, each containing an exhaust and fresh air injector. This enables the fans to be located outside the tunnel, creating a longitudinal flow between shafts that allows the air in the tunnel to be continuously renewed and enables the extraction of exhaust fumes/smoke in the event of a fire.

The turnkey contractor was the Malaysian Mining Corporation (MMC) Berhad–Gamuda Berhad joint venture. Gamuda proposed a public–private funding initiative (PPFI) for the $514m project, with the government financing $342m and the remaining (MMC) Berhad–Gamuda Berhad joint venture under a 40-year concession. $163m being funded by Gamuda and its joint venture partner. The project will be operated by the Malaysian Mining Corporation The MMC–Gamuda JV contracted Mott MacDonald to carry out the feasibility studies for the dual-purpose tunnel and then provide detailed design services to take the project from concept to construction. SSP Consultants were also involved in the tunnel’s design and overseeing the construction.

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