UC research offers solution to strengthen vulnerable buildings
13 September 2011
An innovative solution for strengthening multi-storey concrete buildings was put to the test on the University of Canterbury's shake table earlier this month.
PhD student Patricio Quintana Gallo (left) and Professor Athol Carr explain the shake table testing.
An innovative solution for strengthening multi-storey concrete buildings was put to the test on the University of Canterbury’s shake table earlier this month.
As part of a seven-year Foundation for Research, Science and Technology-funded project on “Seismic Retrofit Solutions for NZ multi-storey buildings” started in 2004, a three-storey reinforced concrete (RC) model building was put through two simulated earthquakes before an audience of staff, students and local television crews.
The particular research being tested – part of PhD student Patricio Quintana Gallo’s thesis project but related to a much wider body of research being carried out by a team from the Civil and Natural Resources Engineering Department led by Associate Professor Stefano Pampanin– was an investigation of the seismic response of non-ductile pre-1970 RC frame buildings, before and after a rehabilitation or retrofit intervention. The objective was to upgrade the performance of such a structure when it is subjected to strong earthquake ground motions.
The model had been retrofitted with GFRP (Glass Fibre Reinforced Polymer) laminates, which are like bandages that can be wrapped around a building’s damaged or vulnerable spots, a solution neither too invasive nor expensive and one that could provide a solution to strengthen this country’s older RC buildings, as well as repair and strengthen the damaged ones, and make them far safer.
The use of advanced composite materials for seismic retrofit prior and after earthquake events is becoming, at an international level, a highly regarded solution as proven by the seismic repair and rehabilitation of many public schools after the L’Aquila earthquake in Italy in 2009.
The first simulation was based on the ground motions recorded in the CBD during last September’s 7.1 magnitude Darfield Earthquake and the second shake test subjected the structure to the same ground motions of Chile’s 8.8 magnitude quake in February 2010, which researchers believe would be relatively similar, in duration and intensity, to what we could expect in Christchurch from major seismic activity on the Alpine Fault.
Patricio said the testing proved that researchers had been able to reverse the “hierarchy of strengths” in the beam column joint region using the GFRP laminates, thus protecting the structure from a soft-storey or “pancake” collapse mechanism, and therefore proved the efficiency of their design for upgrading the performance of these older reinforced concrete buildings.
For more information please contact:
communications@canterbury.ac.nz.
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