An elevated section of an upcoming expressway will be the first land transport infrastructure here to be made terrorist-proof.
The section is a viaduct of the North-South Expressway that will go over Chong Pang Camp.
The military camp, at the junction of Gambas Avenue and Sembawang Road, is home to the Republic of Singapore Air Force (RSAF) units armed with anti-aircraft guns and missiles.
The Land Transport Authority (LTA) has invited consultants to come up with design solutions to neutralise bomb threats from the viaduct that will go over the north-eastern corner of the camp. These could be from explosives on board vehicles, or explosives planted on parts of the viaduct.
The 21km partly underground North-South Expressway, which is estimated to cost $8 billion, will join Upper Thomson to the city. Main construction will start in 2015, and the highway is expected to be ready by 2020.
The portion that goes over Chong Pang Camp is part of an 8.8km viaduct, the longest in Singapore. The LTA said it could not avoid going above the camp, as all the other options were either not feasible or too costly.
It said the cost of the security measures had already been factored into the construction budget.
A spokesman said the move is to protect the camp, rather than the road. He said it will be the first road or rail infrastructure here to incorporate counter- terrorism design features.
According to tender documents obtained by The Straits Times, the design must take into account risks arising from the detonation of up to 500kg of explosives. Risks from fragments and flying debris from such a blast must also be taken into account.
Observers said that to mitigate such risks, the section over - as well as the stretches just before and after - Chong Pang Camp is likely to be enclosed.
The construction could be similar to elevated tunnels that other cities build to reduce traffic noise on viaducts - only much stronger.
Such a structure will not only contain the blast of explosives, but will also prevent the use of grenade launchers and small arms.
Director Li Bing of Nanyang Technological University's Natural Hazard Research Centre said consultants will have to "plan for the worst-case scenario". An expert in the area of anti-terrorist design and evaluation, Professor Li said 500kg of explosives will practically "flatten" everything over an area within a 100m radius. He added that designs could include using "very thick building materials or new materials".