In the heart of the Malaysian capital Kuala Lumpur, an ambitious plan to create a green city within a city where people can live, work and play is being realised on a 29ha site dubbed Kuala Lumpur Sentral. At the core of this grand scheme is Kuala Lumpur Sentral Station (KLSS), a transport hub which will serve the commuter, light and express rail services linking the city with the rest of Malaysia, including the new international airport.
To be developed in phases by a company formed by the Malaysian State Railway Corporation, the Malaysian Resources Corporation and local firms, KL Sentral will feature offices, hotels, condominiums, shops and an auditorium surrounding the rail interchange. KLSS is the first and arguably most important phase of the project, as it will organise the different rail services under one roof and prepare the groundwork for the phases to come.
The project kicked off in March 1997 when a joint venture formed by Dragages and two Malaysian firms, Ekovest and KMZ, was awarded a M$714M ($188M) design and construct contract for KLSS. It covers six elements: a 479,000m3 station and access roads; a 30,000m3 maintenance depot; 18km of new rail tracks; and three decks with transfer plates which will support offices, an auditorium and two hotels.
KLSS will have 12 platforms serving the three rail services. At ground level will be the 10 tracks serving six State Railway lines, which include two intercity lines, four commuter lines; and four express lines. Two light rail lines will pass through at Level 3.
Construction has to be phased due to the size of the project, and the phasing is virtually decided for the contractor by the presence of three operating railway lines and a river which passes through the site.
Rather than opting for a massive diversion exercise once all new lines into the station are in place, the existing tracks are being diverted one by one, gradually freeing up areas for construction. When a new track has been laid at its final location, turnouts are added either side of the 1.5 km long station box, to bring the existing track into the station.
One of the contractor's first tasks at each stage is the diversion of the river, which flows below the existing tracks. In what the contractor calls Phase 0, the river is diverted into a 12m wide, 3m high box culvert, which is installed once the existing tracks have been cut and welded onto new ones during night-time possessions. The original river bed is then backfilled.
The existing tracks occupy a 20m wide area in the middle of the site where work is only allowed for three hours during the night, when the 25 kV catenary system can be temporarily disconnected. Between 1am and 4am, a 30m long U beam is launched above the tracks. This is then used as permanent formwork for deck construction 8m above the live tracks.
As a 3m wide safety corridor has to be maintained on either side of the live tracks, each diversion can free up a substantial amount of space for construction. The contractor has diverted one electrified track so far and freed up areas for work on Precinct A, a deck in the western part of the station which will support office developments; and a deck in the east which will support the auditorium. The project will peak in late 1999 or early 2000, when the second diversion is due to take place.
According to project manager Bruno Botella, changes to the signalling and catenary systems required by the addition of turnouts and the diversions are carefully planned on no fewer than 5,000 drawings.
The load bearing decks which will support building developments above the station are technically regarded as tunnels. Because freight trains passing through these structure will be carrying flammable/dangerous substances such as LPG, two to four-hour rated firewalls have to be put in to separate the passenger and freight tracks to guarantee the safety of passengers.
Other elements which complicate the works include construction of a temporary protective steel structure to encase the elevated light rail tracks on which trains run at two-minute intervals.
Phasing is also required to replace the old railway depot with the new depot and the auditorium. In the first step, half of the 20-track new depot will be built at Precinct F beneath the two future hotels, and operations transferred. The site of the old depot is then cleared to make way for the auditorium and the remainder of the new depot.
KLSS features a curvilinear roof of profiled metal decking supported by a tubular steel structure prefabricated and in storage in Malacca until needed. The sections are welded into 12m long pieces on site and lifted into place by mobile cranes running on tracks set up on the deck to increase the efficiency of the operation.
The central spine of the station will be covered by three hyperbolic- parabolic stainless steel roofs supported by a glazed cone, under which timber domes of Islamic geometry are to be installed.
The station is being built with the same steel formwork used recently on the Kuala Lumpur international airport project. Elsewhere, timber formwork is employed by local workers who are more familiar with traditional methods of construction.
The 260,000m3 of concrete required is produced on site by two batching plants which produce material at a rate of 100m3/h. The project will require 2,600 piles reaching a depth of up to 25m. So far 2,200 piles have been installed.
KLSS will probably become the first rail station in the world to provide both in-town check-in and in-town reclaim facilities for air passengers. According to the client's projection, the station will be used by more than 50M passengers when it opens in 2001, rising to almost 100M in 2020.
Handover to to the client will be phased, beginning in January 2000.