
The 22 February 2011, Mw6.2 Christchurch earthquake is the most costly earthquake to affect New Zealand, causing an estimated 181 fatalities and severely damaging thousands of residential and commercial buildings. This paper presents a summary of some of the observations made by the NSF-sponsored GEER Team regarding the geotechnical/geologic aspects of this earthquake. The Team focused on documenting the occurrence and severity of liquefaction and lateral spreading, performance of building and bridge foundations, buried pipelines and levees, and significant rockfalls and landslides. Liquefaction was pervasive and caused extensive damage to residential properties, water and wastewater networks, high-rise buildings, and bridges. Entire neighborhoods subsided, resulting in flooding that caused further damage. Additionally, liquefaction and lateral spreading resulted in damage to bridges and to stretches of levees along the Waimakariri and Kaiapoi Rivers. Rockfalls and landslides in the Port Hills damaged several homes and caused several fatalities.
A man walks towards a damaged house in Dallington. The chimney has fallen, and roofing tiles have shaken loose. In the foreground, the railings of the damaged Dallington Bridge are visible.
A news item titled, "Oxford Street Bridge Repaired", published on the Lyttelton Harbour Information Centre's website on Thursday, 29 September 2011.
Detail of steel bracing supporting the Colombo Street overpass. The photographer comments, "After the earthquake in Christchurch the Colombo St overpass got damaged and they used reinforcing steel beams to hold it up".
People looking at the damage to Cashel mall from the cordon at the Bridge of Remembrance.
Damage to a building on Durham Street. Wire fencing has been placed around the building as a cordon.
A presentation prepared by one of the site engineers restoring the Memorial Arch and Bridge of Remembrance, outlining the damage to the structures, the repair designs and the construction methodologies.
A photograph of a damaged bridge. The photograph is captioned by BeckerFraserPhotos, "Askeaton Drive, Kaiapoi".
A photograph of a damaged bridge. The photograph is captioned by BeckerFraserPhotos, "Askeaton Drive, Kaiapoi".
A photograph of a detour sign on Ferry Road.
A photograph of IHC Christchurch Earthquake Reflection Group member Rosanne Parrish looking at the damaged Medway Street Bridge.
A photograph of IHC Christchurch Earthquake Reflection Group member Rosanne Parrish looking at the damaged Medway Street Bridge.
Oxford Terrace Baptist Church on the corner of Madras St and Oxford Terrace, and alongside the Central City Fire Station on Kilmore St.
Photograph captioned by BeckerFraserPhotos, "A view looking south down Colombo Street from the bridge over the River Avon. The road damage in the foreground is where the bridge begins".
A damaged driveway bridge over Dudley Creek has been blocked off with warning tape. The sides of the bridge have slumped, and the driveway surface has buckled and cracked. In the background, the gates to the property are misaligned. The photographer comments, "The bridge to a large mansion on a huge section was displaced by half a metre".
A damaged driveway bridge over Dudley Creek has been blocked off with warning tape. The sides of the bridge have slumped, and the driveway surface has buckled and cracked. In the background, the gates to the property are misaligned. The photographer comments, "The bridge into the mansion in Banks Avenue is as broken as the mansion itself".
A damaged driveway bridge over Dudley Creek has been blocked off with warning tape. The sides of the bridge have slumped, and the driveway surface has buckled and cracked. In the background, the gates to the property are misaligned. The photographer comments, "The bridge to a large mansion on a huge section was displaced by half a metre".
A view down Cashel Street from the Bridge of Remembrance, showing earthquake damage to several buildings along Cashel Mall.
A view down Cashel Street from the Bridge of Remembrance, showing earthquake damage to several buildings along Cashel Mall.
The paper proposes a simple method for quick post-earthquake assessment of damage and condition of a stock of bridges in a transportation network using seismic data recorded by a strong motion array. The first part of the paper is concerned with using existing free field strong motion recorders to predict peak ground acceleration (PGA) at an arbitrary bridge site. Two methods are developed using artificial neural networks (a single network and a committee of neural networks) considering influential parameters, such as seismic magnitude, hypocentral depth and epicentral distance. The efficiency of the proposed method is explored using actual strong motion records from the devastating 2010 Darfield and 2011 Christchurch earthquakes in New Zealand. In the second part, two simple ideas are outlined how to infer the likely damage to a bridge using either the predicted PGA and seismic design spectrum, or a broader set of seismic metrics, structural parameters and damage indices.
A photograph looking south-west along Williams Street, from the Williams Street bridge, in Kaiapoi. In the distance is the rebuilt Blackwell's Department Store. The department store was rebuilt after the previous building was damaged in the 2010 and 2011 Canterbury earthquakes.
A damaged driveway bridge over a stream has visibly moved, scraping up some of the driveway. The photographer comments, "Our neighbour Pam Shadbolt's house, immediately behind our house, on the bank of Dudley Creek. The bridge has broken free from its foundations".
Eighty years and then the damage was done. Result of the earthquake on 22/02/11.
Detail of damage to the twisted Medway Street bridge. The photographer comments, "The twisted footbridge at the Medway St corner".
A photograph of IHC Christchurch Earthquake Reflection Group member Rosanne Parrish standing in front of the damaged Medway Street Bridge.
A photograph of damage to the bridge between Avonside Drive and Porritt Park. Large cracks can be seen along the river bank.
A photograph of damage to the bridge between Avonside Drive and Porritt Park. Large cracks can be seen along the river bank.
A document describing Downer's use of column seismic clamps to prevent additional damage to the Arch columns.
Road damage between St Paul's School and Gayhurst Road bridge. The road has slumped near the curb, probably due to liquefaction.
A video of the removal of the earthquake-damaged Medway Street bridge from the banks of the Avon River. The video shows members of the Stronger Christchurch Infrastructure Rebuild Team removing the bridge and preparing it for transport to the Ferrymead Heritage Park. It will remain at the park until a permanent home can be found for it as an earthquake memorial.