Tunnelling projects will have to be designed to be easier to build: BCA

Workers walking in the 1.4km Sentosa Gateway Tunnel.
Workers walking in the 1.4km Sentosa Gateway Tunnel.PHOTO: LIANHE ZAOBAO

SINGAPORE - Tunnelling projects for MRT lines and expressways may become quieter and be completed in a shorter time in future, as their designers will be required to make them easier to build.

The Building and Construction Authority (BCA) said on Wednesday (Jan 6) that it will be expanding a framework now used for buildings to include tunnelling projects.

Under the buildability framework, designers and developers must meet a minimum standard of labour-saving methods and technology or face penalties.

For example, they can use machines and prefabrication - where parts are made elsewhere and brought to the construction site to assemble - and reduce the amount of excavation on site.

BCA chief executive John Keung said civil engineering projects are expected to take up a larger proportion of Singapore's construction demand in the years to come, up from around a quarter now.

"It's not a building, so you've got to find a different way to encourage them to make it easy to build," said Dr Keung, adding that BCA is working with the Land Transport Authority and other regulatory bodies to develop the framework.

For example, tunnel linings could be precast offsite, he said. The aim is to achieve 25 to 40 per cent productivity improvements.

Dr Keung was speaking to the media after a visit to the construction site of three new Nanyang Technological University residential halls which are being built using a more efficient "prefabricated pre-finished volumetric construction" (PPVC) method.

Whole rooms are manufactured overseas, including interior fittings such as lights and fans, then brought to Singapore and fitted out before being brought to the construction site and being stacked into a building.

This "Lego-style" method saves up to 25 to 40 per cent in manpower and 15 to 20 per cent in construction time.

Although this method currently costs around 18 per cent more than conventional concrete construction, Deputy Prime Minister Tharman Shanmugaratnam, who is chairman of the National Productivity Council, said costs can be brought down over time as more suppliers come on board.

"The public sector is taking the lead in building up demand," Mr Tharman said during the visit.

The process involves more high-tech jobs in manufacturing the rooms, and fewer low-tech jobs on the construction site, he said. "We are going to be short of manpower for the long term, we want to offer higher quality jobs, and this is the way to go."

BCA will have 10 integrated construction and prefabrication hubs by 2020 where building components can be made in Singapore.

joseow@sph.com.sg