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Research papers, The University of Auckland Library

This thesis presents the application of data science techniques, especially machine learning, for the development of seismic damage and loss prediction models for residential buildings. Current post-earthquake building damage evaluation forms are developed for a particular country in mind. The lack of consistency hinders the comparison of building damage between different regions. A new paper form has been developed to address the need for a global universal methodology for post-earthquake building damage assessment. The form was successfully trialled in the street ‘La Morena’ in Mexico City following the 2017 Puebla earthquake. Aside from developing a framework for better input data for performance based earthquake engineering, this project also extended current techniques to derive insights from post-earthquake observations. Machine learning (ML) was applied to seismic damage data of residential buildings in Mexico City following the 2017 Puebla earthquake and in Christchurch following the 2010-2011 Canterbury earthquake sequence (CES). The experience showcased that it is readily possible to develop empirical data only driven models that can successfully identify key damage drivers and hidden underlying correlations without prior engineering knowledge. With adequate maintenance, such models have the potential to be rapidly and easily updated to allow improved damage and loss prediction accuracy and greater ability for models to be generalised. For ML models developed for the key events of the CES, the model trained using data from the 22 February 2011 event generalised the best for loss prediction. This is thought to be because of the large number of instances available for this event and the relatively limited class imbalance between the categories of the target attribute. For the CES, ML highlighted the importance of peak ground acceleration (PGA), building age, building size, liquefaction occurrence, and soil conditions as main factors which affected the losses in residential buildings in Christchurch. ML also highlighted the influence of liquefaction on the buildings losses related to the 22 February 2011 event. Further to the ML model development, the application of post-hoc methodologies was shown to be an effective way to derive insights for ML algorithms that are not intrinsically interpretable. Overall, these provide a basis for the development of ‘greybox’ ML models.

Research papers, The University of Auckland Library

The sequence of earthquakes that has affected Christchurch and Canterbury since September 2010 has caused damage to a great number of buildings of all construction types. Following post-event damage surveys performed between April 2011 and June 2011, the damage suffered by unreinforced stone masonry buildings is reported and different types of observed failures are described. A detailed technical description of the most prevalently observed failure mechanisms is provided, with reference to recognised failure modes for unreinforced masonry structures. The observed performance of existing seismic retrofit interventions is also provided, as an understanding of the seismic response of these interventions is of fundamental importance for assessing the vulnerability of similar strengthening techniques when applied to unreinforced stone masonry structures.

Images, UC QuakeStudies

A photograph of the earthquake-damaged buildings down Tuam Street taken shortly after the 22 February 2011 earthquake. Members of the public are waking over the rubble as they attempt to leave the city.

Images, UC QuakeStudies

A photograph of the earthquake damage to Poplar Street taken from Tuam Street shortly after the 22 February 2011 earthquake. The road is completely covered by loose bricks and a car has been crushed.

Images, UC QuakeStudies

A photograph of police and members of the public people standing near the earthquake damaged Smiths City car park after the 22 February 2011 earthquake. Liquefaction covers the right side of the footpath.

Images, UC QuakeStudies

A photograph of police and members of the public people standing near the earthquake damaged Smiths Citys car park after the 22 February 2011 earthquake. Liquefaction covers the right side of the footpath.

Images, UC QuakeStudies

A photograph of the earthquake damage to Poplar Street taken from Tuam Street shortly after the 22 February 2011 earthquake. The road is completely covered by loose bricks and a car has been crushed.

Images, UC QuakeStudies

A photograph of the earthquake damage to Poplar Street taken from Tuam Street shortly after the 22 February 2011 earthquake. The road is completely covered by loose bricks and a car has been crushed.

Images, UC QuakeStudies

Damage to a house in Richmond. Stucco underneath a window has cracked, and the foundation appears to be on a lean. The photographer comments, "These photos show our old house in River Rd and recovery work around Richmond and St Albans. The bay window of our bedroom has jumped off the foundations, cracking the stucco".