SINGAPORE - The walls of large buildings may be able to withstand a bombing from the outside, but the impact may still cause concrete and bricks to come loose at high speeds that may injure or even kill those inside.
Scientists from the Defence Science and Technology Agency (DSTA) are working on minimising this hazard known as "spalling", by using mats made of fibre reinforced polymer (FRP).
The mats, which can be applied to the walls of vital existing structures, can act as nets, catching debris and preventing it from harming those inside.
DSTA tested the blast response of such reinforced concrete walls as part of a series of experiments known as the Explosive Testing of Structural Components (ETSC) on Wednesday (May 17).
This year's test, which is the sixth held here since the programme began in 1994, started on Monday and will go on till May 27 on Pulau Senang, an island off the south-west coast of mainland Singapore.
Defence Minister Ng Eng Hen, accompanied by senior officials from the Ministry of Defence and the Singapore Armed Forces (SAF), attended the ETSC on Wednesday, which is meant to assess and collect data on new concepts in protective structures.
The ETSC supports the SAF in the design and development of critical buildings in light of a heightened level of threat, and has applications in a non-military context as well.
In a Facebook post on Thursday about the visit, Dr Ng said the information about the FRP will be used to build homes and bomb shelters that can better protect civilians.
The application of FRP to walls was found to make them 2.5 times more resistant to blast effects. It has applications as a cost-effective means of enhancing blast resiliency of existing buildings as it requires minimal tear-down and reconstruction.
"For example, using better design and materials, bomb shelters can have thinner walls or shorter setbacks and yet remain just as survivable. This new information provide us better options in building HDB homes," he added.
DSTA also experimented on a variety of concepts and structures, including an alternative design for storing ammunition through an arch structure that is deemed safer in the event of an accidental explosion from within.
During the ETSC tests, only the door of the arched structure was destroyed, while the rest of it remained intact, minimising the possible hazard.
The ETSC also carried out tests on the usage of steel jackets in protecting building column, in collaboration with the Ministry of Home Affairs.
The design consists of an additional layer of steel that can be applied on newly constructed buildings or retrofitted on existing ones, and is meant to increase the resistance of critical structures to attacks from improvised explosive devices.