img(height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=2939831959404383&ev=PageView&noscript=1")

Stainless steel nodes resist earthquake damage

Words:
Stephen Cousins

Researchers develop ‘earthquake-proof’ device that limits residual drift in buildings to improve prospects for repair

Researchers at Heriot-Watt University have developed an expendable device to ‘earthquake-proof’ buildings that absorbs seismic shocks and make structures easier to repair.

The stainless steel nodes are strategically positioned at the joints between diagonal braces and horizontal beams in steel framed buildings. When a building starts to shake, they absorb the seismic loads, mitigating damage to the rest of the structure. Post-quake they are simply removed and replaced so the building can return to normal occupation quickly.

The system is intended to improve on current European ‘earthquake-proof’ buildings, which are designed to prevent collapse in the event of a strong earthquake, but do not prevent non-repairable damage or deformations caused by ‘residual drift’. Residual drift is caused when the accumulation of damage means buildings are unable to return to their original vertical orientation.

Dr George Vasdravellis, assistant professor of structural engineering at Heriot-Watt University in Edinburgh, told RIBAJ: ‘This is a major problem that makes repairs very difficult and expensive due to tolerance issues. Our system mitigates against the need for damage repair and virtually eliminates residual drift so the building remains almost vertical.’

Critical to the technology is the use of stainless steel for the nodes; its high post-yield stiffness causes them to crumple before the rest of the building structure

The system is designed to handle severe 1-in-475-year seismic events in buildings up to 10 storeys high. Experimental testing and computer simulations recorded negligible residual drift, compared to conventional building designs where drifts were four to five times larger.

Critical to the technology is the use of stainless steel for the nodes; its high post-yield stiffness causes them to crumple before the rest of the building structure.

According to Vasdravellis, the number of sacrificial devices required could range from two to six, depending on the building. He says: ‘The diameter of the devices determines the strength, so you can increase or reduce the number of devices depending on the strength required.’ The devices only work in conjunction with regular concentrically-braced steel building frames and in future it may be possible to retrofit them into existing buildings of this type.

Vasdravellis was awarded £140,000 by the European Commission for the next stage of his research into earthquake engineering. ‘The next step is to develop the technology for multi-hazard mitigation, to handle other impacts, such as progressive collapse, when a critical structural element in a building, like a column, is suddenly removed due to a bomb blast or other issues,’ he concludes.

Latest

Embodied carbon and how best to use limited resources took centre stage at the RIBA’s most recent Smart Practice conference

How can we break our addictions to fossil fuels, waste and consumption?

Strengthening the 18th century, timber-framed Corn Exchange and connecting it to an upgraded 1930s Studio Theatre were key to opening the arts centre to modern audiences

How FCBStudios and Max Fordham refurbished the listed Corn Exchange and Studio Theatre

Western modernism came to colonial West Africa and India, but with independence they made it their own. Tropical Modernism: Architecture and Independence follows the story

Locals made ‘progressive, optimistic’ style their own

Bid to be one of six to join a new four-year Somerset and Wiltshire framework, revitalise an historic East of England city centre or help tell the tale of Cornwall. These are some of the latest architecture contracts and competitions from across the industry

Latest: £6m West Country architectural services agreement

Will Burges’ self-build family home in suburban south London is inhabited and looks finished, but this flexible, future-looking house is intended to be a work in progress

It looks complete, but Will Burges’ house is intended never to be truly finished