A CLOSE focus on risk management and value engineering enabled Hong Kong rail operator Kowloon & Canton Railway Corporation (KCRC) to slash $2bn from the cost of building its new West Rail line, UK engineers heard last month.
The $5.12bn West Rail project consists of 30.5km of line, 14.4km of which is on viaduct and 14.7km in tunnel (NCEI January).
On its way from central Hong Kong out through the New Territories towards the Chinese border the line traverses reclaimed ground and flood channels, nature reserves and densely packed suburbs. In all there are nine stations, plus a state of the art maintenance depot.
Mapping out the hugely complex project to a joint ICE, Institution of Mechanical Engineers and Hong Kong Institution of Engineers meeting, KCRC senior director for capital projects James Blake said that political and press interest in the project was intense.
Any technical or financial problems would have been incendiary, he suggested.
Close project management and interaction between client and contractors was key to cost control, Blake said.
The project kicked off in 1997 with technical studies establishing West Rail's alignment and around 25% of design to completion.
'This enabled the project to be fixed in terms of capital expenditure budget, the acquisition of land, funding cost and pre-revenue operation expenditure - $7.12bn in money of the day, ' Blake recalled.
'A multi-contract approach to construction was adopted to ensure that the corporation had maximum visibility over the performance of contractors and work in progress.
'Given that KCRC had not previously built stations of such complexity, a fully designed approach was adopted for the civil works, building services, architectural building services and finishing works.
'Contractors were required to provide resources for integration of works by the system specialist contractors, ' Blake said.
The first major savings were achieved on viaduct design, Blake explained: 'Parallel work was undertaken on foundations and superstructure to maximise constructability and minimise the overall programme duration for viaduct construction.
'At the same time, we realised that contractors would propose alternative designs and these could be accepted.'
This resulted in major design refinements, with the viaduct built as a series of portal frame structures rather than as a conventional continuous deck running over discrete piers.
A value engineering exercise carried out at the same time revealed that to carry the targeted figure of 1.1M passengers a day KCRC could increase the frequency of trains by using state of the art moving block signalling.
This would enable the operator to reduce the length of trains from 12 cars to nine. The 25% saving on train length enabled corresponding reductions in platform length and the size of stations.
Meanwhile, KCRC adopted design and build for the tunnel component of West Rail.
The first 5.5km length was driven by conventional rock tunnel methods. But where KCRC's outline design was for twin bore construction, the contractor's alternative was to build a single tunnel with a central wall to provide separation for fire safety and passenger evacuation.
The section of tunnel after Tsuen Wan West station was again a contractor alternative design, this time using an earth pressure balance tunnel boring machine.
'The ability to tunnel at shallow depth in decomposed soil and rock conditions without serious disturbance at ground level avoided cut and cover construction, which would have impacted on the major roads above the tunnel alignment, ' said Blake.
To guarantee it received the lowest possible bids KCRC took on risk for unforeseen ground conditions on all but the tunnel contracts.
Terrain across much of the alignment was so challenging, consisting of fractured marble and limestone, that contractors would either have been unwilling to bid, or would have put in prices that broke KCRC's upper spending limit, Blake said.
KCRC's $2bn saving was aided by the recent completion of work on Hong Kong's new Chek Lap Kok airport, which left many of the territory's major contractors with spare capacity.
And the cancellation of many commercial building projects as Hong Kong reeled from Asia's economic flu helped drive down costs further.