Researchers in New Zealand have developed new technology that could make bridges more resilient to earthquakes. Their so-called ‘low-damage solution’ has a series of rocking bridge columns that move with seismic shocks, leaving bridges with little to no damage compared to conventional building methods.
More than 900 bridges were damaged during the Kaikōura earthquake on New Zealand’s South Island in 2016. Roads and railway lines were also destroyed, disrupting the transport network.
Researchers at the University of Canterbury have said that although current designs prevent the collapse of bridges, significant repairs might be needed.
They’ve developed flexible columns made of high-strength steel that move during an earthquake. They act like giant rubber bands to bring bridge supports back into position. Conventional steel bars are also used to dissipate seismic energy, reducing the impact of a powerful tremor.
Alessandro Palermo, a professor in Structural Engineering and Materials at the University of Canterbury, says the technology makes bridges more resilient.
“This special steel, which is usually placed in the middle of the column, is actually working as a rubber band. So, during the earthquake this high-strength steel is actually trying to bring the pier back to the original position," Palermo said. "And we are actually trying to combine these resilience-solutions - seismic resilience-solutions - with accelerated bridge construction. How can we actually build bridges faster and at the same time (be) resilient? This system allows (us) to do that.”
In February 2011, the New Zealand city of Christchurch was hit by a magnitude 6.3 earthquake. 185 people were killed and several thousand injured.
A decade later, rebuilding work continues.
Each year, more than 15,000 earthquakes are detected in New Zealand.
Only about 150 are large enough to be felt, but building homes, offices and bridges that can withstand major tremors is a priority.