An earthquake struck New Zealand’s South Island on September 2, 2010, and the city of Christchurch just missed its epicenter by about 40 kilometers or 25 miles. Disaster struck almost six months later when an aftershock concentrated on the city, killing 185 people and injuring many more. The sequence also caused an estimated $ 40 billion damage.
In response, the New Zealand government formed the Canterbury Earthquakes Royal Commission to investigate the consequences, and particularly building failures. They developed a list of recommendations for the New Zealand government to implement.
“There was a very strong drive to actually make change happen,” said Professor Rick Henry, senior lecturer in the Department of Civil and Environmental Engineering at the University of Auckland. “To our advantage as engineers, we had some specific recommendations that we could point out.”
These recommendations formed the basis for revisions of the New Zealand standard for concrete structures NZS 3101 and subsequently the requirements of the US Building Code Requirements for Structural Concrete ACI 318.
Henry and colleagues generated the first of their kind data on lightly reinforced concrete walls commonly used in multi-story buildings in areas of low or moderate seismicity around the world. The dataset was published and made publicly available on the National Science Foundation-funded DesignSafe cyber infrastructure of the Natural Hazards Engineering Research Infrastructure (NHERI).
Rick Henry and Yiqiu Lu, research fellows in Henry’s laboratory at the University of Auckland, were awarded the DesignSafe Dataset Award 2021, which recognizes the diverse contributions of the data set to natural hazard research.
“In earthquake engineering, we see DesignSafe as the most visible platform on which publishing this data would allow most users to find and use it,” said Henry.
The researchers began their investigations by marveling at the damage to the wall they saw from the Canterbury earthquake. They noted the lack of distributed cracks in what engineers call “plastic hinges,” such as the base of the wall, where they expected more flexing in response to floor tremors.
“There were very few cracks in the walls that should have withstood large deformations,” explained Henry. “Investigators found that all of the steel reinforcement was broken or broken. It was hidden damage in the wall that raised many concerns. Why did we get that? “
Henry and Lu focused on simulating the seismic loads on walls in the laboratory, testing 11 wall components with about 80 sensors to measure their deformations and strains with increasingly applied loads that simulated seismic effects from increasingly larger earthquakes.
The high-quality documentation and data set they generate includes details on the test walls, their material properties, test setup, instrumentation plan, load protocol, test sequences, test observations, crack images, photos, videos, time-lapse animations and sensor data.
An article on the dataset was published in the March 2021 issue of the American Society of Civil Engineers’ Journal of Structural Engineering.
“We looked at how we put limits on wall design to make sure we were getting the performance we needed,” said Henry. “There weren’t many tests of what we thought were lightly reinforced walls.”
Much of what Henry’s lab does to understand structural responses is either to test physical components or to develop numerical simulations. He stressed that they go hand in hand.
“Sometimes we see things in earthquakes and sometimes we see things in the lab,” he said. “They all help us to improve our understanding of it. A really useful result of physical testing is that we can use it to calibrate and verify models that could be used to design buildings. “
He explained that earthquake engineering can be broadly categorized into two categories. One is for existing buildings that may not meet current standards.
“Can we predict and understand what buildings will do in the event of an earthquake,” postulated Henry. “In particular, how do we need to intervene or strengthen them in order to improve their performance?”
Second, there is the new build category and the general improvement in the design process.
“Most of what we focus on is applied in this applied area of research. To be able to put what we have done into practice and to see a change in new design or some engineering practice as a result of our work is the goal of our work, ”said Heinrich.
Henry’s work on wall tests was funded by the New Zealand Department of Economics, Innovation and Employment (MBIE) and, more recently, by the New Zealand Center for Earthquake Resilience (QuakeCORE), a partnership with DesignSafe.
DesignSafe is a comprehensive cyber infrastructure that is part of the NSF-funded Natural Hazard Engineering Research Infrastructure (NHERI) that provides cloud-based tools to manage, analyze, understand and publish critical data for research to understand the effects of natural hazards. The capabilities within the DesignSafe infrastructure are available free of charge to all researchers working in the field of natural hazards. The cyber infrastructure and software development team is based at the Texas Advanced Computing Center (TACC) at the University of Texas at Austin, with a team of natural hazard researchers from the University of Texas, Florida Institute of Technology and Rice University, consisting of the Senior Management Team.
NHERI is supported by several National Science Foundation grants including DesignSafe Cyberinfrastructure, Award # 1520817.