A team of engineering researchers from the University of Canterbury (UC) in New Zealand is using post-earthquake data, gathered from the city’s own recent disaster, to evaluate the methods and models used to predict the expected damage to multi-storey reinforced concrete buildings.
By comparing the outcome of diverse analytical and numerical (computer-based) models, from the simplest to the most complex, the team aims to develop and implement more practical and efficient building safety improvements.
UC structural engineering professor Stefano Pampanin admits that looking at the impact on buildings from the Canterbury earthquake sequence has confirmed the complexity of reproducing and accurately predicting how buildings respond to earthquake motions.
“Reproducing or predicting the seismic behaviour of portions of existing buildings under controlled conditions and simulated earthquake loading in a laboratory is already quite a challenging task,” he said.
“Dealing with the actual three-dimensional behaviour of real buildings, including structural and non-structural elements, foundation systems and soil conditions, subject to highly uncertain ground motions, is clearly an even more challenging task.”
The research project is borne out of the new normal for existing buildings needing to be evaluated using the best available methodologies to allow clients and insurers to make decisions about repairing versus demolition, or strengthening the building.
“While the best methods and models available are used, it’s a complex problem, and different assumptions at various steps of the many methods and approaches can lead to different answers. Common reference points or benchmarks are therefore vital,” explained Pampanin.
“The more the various professionals involved in this area work together the better. With the data gathered during the Canterbury earthquakes, we have a unique and valuable opportunity to verify and improve the accuracy and usefulness of the various methods and models used to analyse building performance, and provide engineers with simple but reliable tools for everyday use.”
The research team includes both a strong international network as well as local engineering students, who have been challenged with the task of sifting through mountains of technical articles, guidelines and international codes, scrutinising engineering drawings and conducting numerous computer model simulations.
“There are no course readers or textbooks. This is a very complex area. In earthquake structural engineering there is no single mathematical equation that can provide you with the correct answer. It is a matter of having a holistic view and putting together all the evidence and information to draw conclusions and allow the end-user to make an informed decision,” said third year student Danny Garry.
“Good benchmarking or cross-validation between engineers and other technical operators to agree and maintain consistency is very important,” said fellow student researcher Henry Wakefield.
The findings will be presented to the University’s civil and natural resources engineering research conference later this month.