A group of engineers from New Zealand has been awarded a prestigious award for their work in the Canterbury Earthquakes that started on the 4th of September, 2010 and continued into 2011. After the earthquake, the engineers started to research liquefaction damage to hopefully earthquake-proof roads and buildings for any future seismic activity. Liquefaction damage refers to the breakdown of soil during an earthquake that splits roads in two and causes some devastation for houses and buildings.
The leader of the team, Sjoerd Van Ballegooy, walked away with the Outstanding Paper Award from the Earthquake Engineering Research Institute in San Francisco.
According to Stuff, their research consisted of 81,000 visits to the homes that were damaged as a result of the earthquakes and did tests on “ground motions and depth to groundwater.”
Van Ballegooy said, “Much of eastern Christchurch has been built on sand and silty soil, with shallow ground water, setting the stage for extensive liquefaction damage to occur following strong earthquake shaking. To make matters worse, thousand of homes were built on non-robust concrete slab foundations, resulting in a significant portion of the residential building portfolio being damaged beyond economic repair as a result of the liquefaction.”
According to Voxy, the Canterbury earthquakes caused the most extensive liquefaction damage ever seen in built up urban areas.
“When we began analysing all of this information we discovered that in some areas, the damage caused by liquefaction was much worse after the shaking on 13 June 2011 and 23 December 2011 despite those earthquakes being significantly smaller than the previous ones on 4 September 2010 and 22 February 2011,” Van Ballegooy said.
He went on to relay their findings, saying, “A combination of lateral spreading, removal of the sand and silt that was ejected to the ground surface, densification of the subsurface materials and tectonic subsidence occurring over four main events were the major factors that contributed to the reduction in thickness of the non-liquefying crust.”
The researchers concluded their findings by urging private insurers, policy makers, architects, engineers, urban planners and other professionals to “reduce the economic and social impact of liquefaction related damage” for the future earthquakes that could possibly happen.