Natural catastrophes are increasing worldwide. They are becoming more frequent but also more severe and impactful on our built environment leading to extensive damage and losses. Earthquake events account for the smallest part of natural events; nevertheless seismic damage led to the most fatalities and significant losses over the period 1981-2016 (Munich Re). Damage prediction is helpful for emergency management and the development of earthquake risk mitigation projects. Recent design efforts focused on the application of performance-based design engineering where damage estimation methodologies use fragility and vulnerability functions. However, the approach does not explicitly specify the essential criteria leading to economic losses. There is thus a need for an improved methodology that finds the critical building elements related to significant losses. The here presented methodology uses data science techniques to identify key building features that contribute to the bulk of losses. It uses empirical data collected on site during earthquake reconnaissance mission to train a machine learning model that can further be used for the estimation of building damage post-earthquake. The first model is developed for Christchurch. Empirical building damage data from the 2010-2011 earthquake events is analysed to find the building features that contributed the most to damage. Once processed, the data is used to train a machine-learning model that can be applied to estimate losses in future earthquake events.
A paper prepared for the Ozwater 2013 conference detailing the story of the damage to, and subsequent repair of, Huntsbury Reservoir.
Helicopter Flight over Christchurch New Zealand
The 2010-2011 Christchurch earthquakes generated damage in several Reinforced Concrete (RC) buildings, which had RC walls as the principal resistant element against earthquake demand. Despite the agreement between structural engineers and researchers in an overall successfully performance there was a lack of knowledge about the behaviour of the damaged structures, and even deeper about a repaired structure, which triggers arguments between different parties that remains up to these days. Then, it is necessary to understand the capacity of the buildings after the earthquake and see how simple repairs techniques improve the building performance. This study will assess the residual capacity of ductile slender RC walls according to current standards in New Zealand, NZS 3101.1 2006 A3. First, a Repaired RC walls Database is created trying to gather previous studies and to evaluate them with existing international guidelines. Then, an archetype building is designed, and the wall is extracted and scaled. Four half-scale walls were designed and will be constructed and tested at the Structures Testing Laboratory at The University of Auckland. The overall dimensions are 3 [m] height, 2 [m] length and 0.175 [m] thick. All four walls will be identical, with differences in the loading protocol and the presence or absence of a repair technique. Results are going to be useful to assess the residual capacity of a damaged wall compare to the original behaviour and also the repaired capacity of walls with simpler repair techniques. The expected behaviour is focussed on big changes in stiffness, more evident than in previously tested RC beams found in the literature.
A photograph of an earthquake-damaged suitcase in the South Quad of the Christchurch Arts Centre. The suitcase is resting on a pile of scaffolding which had been constructed around the Observatory tower. The scaffolding collapsed along with the tower during the 22 February 2011 earthquake.
A pdf copy of a PowerPoint presentation prepared for the Ozwater 2013 conference detailing the story of the damage to, and subsequent repair of, Huntsbury Reservoir.
Working at getting things out of the Victoria Square before it is demolished. www.stuff.co.nz/the-press/news/christchurch-earthquake-20... What I found on my walk around the city January 15, 2014 Ch...
As a result of the Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. Experience from 2010 Chile indicates that it is possible to repair severely damaged concrete elements (see photo at right), although limited testing has been performed on such repaired components. The first phase of this project is focused on the performance of two lightly-reinforced concrete walls that are being repaired and re-tested after damage sustained during previous testing.
A photograph of the platform for the Townsend Telescope amongst the rubble of the Observatory tower at the Christchurch Arts Centre. The tower collapsed during the 22 February 2011 earthquake, severely damaging the telescope.
A photograph of the earthquake damage to the Observatory tower at the Christchurch Arts Centre. The top two storeys of the tower collapsed during the 22 February 2011 earthquake and the rubble spilled into the courtyard in front. A digger was used to clear the rubble away from the building. A tarpaulin has been draped over the top of the tower.
Oxford Terrace Baptist Church on the corner of Madras St and Oxford Terrace, and alongside the Central City Fire Station on Kilmore St.
High demolition rates were observed in New Zealand after the 2010-2011 Canterbury Earthquake Sequence despite the success of modern seismic design standards to achieve required performance objectives such as life safety and collapse prevention. Approximately 60% of the multi-storey reinforced concrete (RC) buildings in the Christchurch Central Business District were demolished after these earthquakes, even when only minor structural damage was present. Several factors influenced the decision of demolition instead of repair, one of them being the uncertainty of the seismic capacity of a damaged structure. To provide more insight into this topic, the investigation conducted in this thesis evaluated the residual capacity of moderately damaged RC walls and the effectiveness of repair techniques to restore the seismic performance of heavily damaged RC walls. The research outcome provided insights for developing guidelines for post-earthquake assessment of earthquake-damaged RC structures. The methodology used to conduct the investigation was through an experimental program divided into two phases. During the first phase, two walls were subjected to different types of pre-cyclic loading to represent the damaged condition from a prior earthquake, and a third wall represented a repair scenario with the damaged wall being repaired using epoxy injection and repair mortar after the pre-cyclic loading. Comparisons of these test walls to a control undamaged wall identified significant reductions in the stiffness of the damaged walls and a partial recovery in the wall stiffness achieved following epoxy injection. Visual damage that included distributed horizontal and diagonal cracks and spalling of the cover concrete did not affect the residual strength or displacement capacity of the walls. However, evidence of buckling of the longitudinal reinforcement during the pre-cyclic loading resulted in a slight reduction in strength recovery and a significant reduction in the displacement capacity of the damaged walls. Additional experimental programs from the literature were used to provide recommendations for modelling the response of moderately damaged RC walls and to identify a threshold that represented a potential reduction in the residual strength and displacement capacity of damaged RC walls in future earthquakes. The second phase of the experimental program conducted in this thesis addressed the replacement of concrete and reinforcing steel as repair techniques for heavily damaged RC walls. Two walls were repaired by replacing the damaged concrete and using welded connections to connect new reinforcing bars with existing bars. Different locations of the welded connections were investigated in the repaired walls to study the impact of these discontinuities at the critical section. No significant changes were observed in the stiffness, strength, and displacement capacity of the repaired walls compared to the benchmark undamaged wall. Differences in the local behaviour at the critical section were observed in one of the walls but did not impact the global response. The results of these two repaired walls were combined with other experimental programs found in the literature to assemble a database of repaired RC walls. Qualitative and quantitative analyses identified trends across various parameters, including wall types, damage before repair, and repair techniques implemented. The primary outcome of the database analysis was recommendations for concrete and reinforcing steel replacement to restore the strength and displacement capacity of heavily damaged RC walls.
A close-up photograph of parts of the Townsend Telescope recovered from the rubble of the Observatory tower. The telescope was housed in the tower at the Christchurch Arts Centre. It was severely damaged when the tower collapsed during the 22 February 2011 earthquake.
A photograph of parts of the Townsend Telescope recovered from the rubble of the Observatory tower. The telescope was housed in the tower at the Christchurch Arts Centre. It was severely damaged when the tower collapsed during the 22 February 2011 earthquake.
A photograph of the earthquake damage to the Observatory tower at the Christchurch Arts Centre. The top two storeys of the tower collapsed during the 22 February 2011 earthquake and the rubble spilled into the courtyard in front. A digger was used to clear the rubble away from the building. A tarpaulin has been draped over the top of the tower and the roof of the building behind.
A photograph of the earthquake damage to the Observatory tower at the Christchurch Arts Centre. The top two storeys of the tower collapsed during the 22 February 2011 earthquake and the rubble spilled into the courtyard in front. A digger was used to clear the rubble away from the building. A tarpaulin has been draped over the top of the broken tower and the roof behind.
A photograph of the earthquake damage to the Observatory tower at the Christchurch Arts Centre. The top two storeys of the tower collapsed during the 22 February 2011 earthquake and the rubble spilled into the courtyard in front. A digger was used to clear the rubble away from the building. A tarpaulin has been draped over the top of the broken tower and the roof behind.
A photograph of the earthquake damage to the Observatory tower at the Christchurch Arts Centre. The top two storeys of the tower collapsed during the 22 February 2011 earthquake and the rubble spilled into the courtyard in front. A digger was used to clear the rubble away from the building. A tarpaulin has been draped over the top of the broken tower and the roof behind.
The earthquake re-pair work has started on the Knox Church on Bealey Avenue, August 14, 2013 Christchurch New Zealand. While building after building is torn down in Christchurch, plans are in place to ensure as much of a 131-year-old church is retained as possible. Knox Church on Bealey Avenue suffered major damage in the February 22 earthquak...
A close-up photograph of parts of the Townsend Telescope recovered from the rubble of the Observatory tower. The telescope was housed in the tower at the Christchurch Arts Centre. It was severely damaged when the tower collapsed during the 22 February 2011 earthquake.
A photograph of the earthquake damage to the second story of the Observatory tower at the Christchurch Arts Centre. The front of the storey has collapsed, exposing the inside. A tarpaulin has been draped over the top and the roof of the building behind.
A photograph of the largest section of the Townsend Telescope recovered from the rubble of the Observatory tower. The telescope was housed in the tower at the Christchurch Arts Centre. It was severely damaged when the tower collapsed during the 22 February 2011 earthquake.
A photograph of the earthquake-damaged Observatory tower at the Christchurch Arts Centre. The photograph was taken using a cellphone camera. The top of the tower collapsed during the 22 February 2011 earthquake. The rubble from the tower has been cleared and a tarpaulin has been placed over the top of the broken tower. Tyres have been placed on the tarpaulin to hold it down. A temporary roof has also been constructed over the tower to keep out the rain.
Posters which describe the earthquake damage, planned restoration methods and historic information about the Bridge of Remembrance and Memorial Arch. These posters were hung on the fencing around the Bridge and Arch to inform the public about the work taking place.
A photograph of the earthquake-damaged Observatory tower at the Christchurch Arts Centre. The photograph was taken using a cellphone camera. The top of the tower collapsed during the 22 February 2011 earthquake. The rubble from the tower has been cleared and a tarpaulin has been placed over the top of the broken tower. Tyres have been placed on the tarpaulin to hold it down. A temporary roof has also been constructed over the tower to keep out the rain. Two vehicles are parked in front.
An outline, created in 2011, of the levels of service and condition of the horizontal infrastructure within the central city, providing a broad indication of damage, service levels provided to residents and business owners, and used to estimate the cost of repairs following the earthquake events.
Earthquake damaged building on a Walk around the city, May 1, 2014 Christchurch New Zealand. Demolition work on Christchurch's "distinctive" former civic building is under way. The category-2 heritage building was designed by G A J Hart and opened in 1939 as the Miller's department store. It featured the South Island's first escalator, which...
The city of Christchurch has experienced over 10,000 aftershocks since the 4th of September 2010 earthquake of which approximately 50 have been greater than magnitude 5. The damage caused to URM buildings in Christchurch over this sequence of earthquakes has been well documented. Due to the similarity in age and construction of URM buildings in Adelaide, South Australia and Christchurch (they are sister cities, of similar age and heritage), an investigation was conducted to learn lessons for Adelaide based on the Christchurch experience. To this end, the number of URM buildings in the central business districts of both cities, the extent of seismic strengthening that exists in both cities, and the relative earthquake hazards for both cities were considered. This paper will report on these findings and recommend strategies that the city of Adelaide could consider to significantly reduce the seismic risk posed by URM buildings in future earthquake.
A photograph of staff from the Department of Physics and Astronomy from the University of Canterbury recovering parts of the Townsend Telescope from the rubble of the Observatory tower. The telescope was housed in the tower at the Christchurch Arts Centre. It was severely damaged when the tower collapsed during the 22 February 2011 earthquake.
A photograph of staff from the Department of Physics and Astronomy from the University of Canterbury recovering parts of the Townsend Telescope from the rubble of the Observatory tower. The telescope was housed in the tower at the Christchurch Arts Centre. It was severely damaged when the tower collapsed during the 22 February 2011 earthquake.