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Research papers, University of Canterbury Library

Live monitoring data and simple dynamic reduced-order models of the Christchurch Women’s Hospital (CWH) help explain the performance of the base isolation (BI) system of the hospital during the series of Canterbury earthquakes in 2011-2012. A Park-Wen-Ang hysteresis model is employed to simulate the performance of the BI system and results are compared to measured data recorded above the isolation layer and on the 6th story. Simplified single, two and three degree of freedom models (SDOF, 2DOF and 3DOF) show that the CWH structure did not behave as an isolated but as a fixed-base structure. Comparisons of accelerations and deflections between simulated and monitored data show a good match for isolation stiffness values of approximately two times of the value documented in the design specification and test protocol. Furthermore, an analysis of purely measured data revealed very little to no relative motion across the isolators for large events of moment magnitude scale (Mw) 5.8 and 6.0 that occurred within 3 hours of each other on December 23, 2011. One of the major findings is that the BI system during the seismic events on December 23, 2011 did not yield and that the superstructure performed as a fixed-base building, indicating a need to reevaluate the analysis, design and implementation of these structures.

Images, UC QuakeStudies

A photograph of a house at 7 Rees Street. The side of the house has been covered in plastic sheeting. Plywood has been used to board up the door. The number of the house has been spray-painted on the wall next to the door. The letterbox of the house next door also has its house number spray-painted on it.

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. A massive 7.4 magnitude earthquake has hit Christchurch and the wider South Island, causing widespread damage, two serious injuries and power cuts to most of the city. Clinton Gooch was awake when the quake hit and was running downstairs to get outside when the wall of his flat collapsed causing the windows to shatter in the shop below".

Images, UC QuakeStudies

The Cranmer Court building, on the corner of Kilmore and Montreal Streets, after the 22 February 2011 earthquake. Large pieces of the building have collapsed, including the octagonal corner section that housed Plato Creative from March 2008 to November 2009. Masonry has fallen onto the footpath and road, and the site has been enclosed in a safety fence to keep people away. The whitewashed interior walls of one of the apartments can be seen.

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. A massive 7.4 magnitude earthquake has hit Christchurch and the wider South Island, causing widespread damage, two serious injuries and power cuts to most of the city. Marsha Witehira had the bricks from the wall of her house fall onto her bed where she was sleeping. Both sides of her house have collapsed. Witehira (L) is comforted by a friend".

Images, UC QuakeStudies

A information board on the fence around the Homestead at Mona Vale. It says 'This hertiage building is managed by the Christchurch City Council on behalf of the city's residents. Until recently it served as a restaurant and function centre. This building was damaged in the 2010/2011 Canterbury earthquakes and ongoing aftershocks. Propping walls and other support is designed to keep the building weather-proof until a decision about its future can be made'.

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. A massive 7.4 magnitude earthquake has hit Christchurch and the wider South Island, causing widespread damage, two serious injuries and power cuts to most of the city. Marsha Witehira had the bricks from the wall of her house fall onto her bed where she was sleeping. Both sides of her house have collapsed. Witehira (R) is comforted by a friend".

Research papers, University of Canterbury Library

This thesis studies the behaviour of diaphragms in multi-storey timber buildings by providing methods for the estimation of the diaphragm force demand, developing an Equivalent Truss Method for the analysis of timber diaphragms, and experimentally investigating the effects of displacement incompatibilities between the diaphragm and the lateral load resisting system and developing methods for their mitigation. The need to better understand the behaviour of diaphragms in timber buildings was highlighted by the recent 2010-2011 Canterbury Earthquake series, where a number of diaphragms in traditional concrete buildings performed poorly, compromising the lateral load resistance of the structure. Although shortcomings in the estimation of force demand, and in the analysis and design of concrete floor diaphragms have already been partially addressed by other researchers, the behaviour of diaphragms in modern multi-storey timber buildings in general, and in low damage Pres-Lam buildings (consisting of post-tensioned timber members) in particular is still unknown. The recent demand of mid-rise commercial timber buildings of ten storeys and beyond has further highlighted the lack of appropriate methods to analyse timber diaphragms with irregular floor geometries and large spans made of both light timber framing and massive timber panels. Due to the lower stiffness of timber lateral load resisting systems, compared with traditional construction materials, and the addition of in-plane flexible diaphragms, the effect of higher modes on the global dynamic behaviour of a structure becomes more critical. The results from a parametric non-linear time-history analysis on a series of timber frame and wall structures showed increased storey shear and moment demands even for four storey structures when compared to simplistic equivalent static analysis. This effect could successfully be predicted with methods available in literature. The presence of diaphragm flexibility increased diaphragm inter-storey drifts and the peak diaphragm demand in stiff wall structures, but had less influence on the storey shears and moments. Diaphragm force demands proved to be significantly higher than the forces derived from equivalent static analysis, leading to potentially unsafe designs. It is suggested to design all diaphragms for the same peak demand; a simplified approach to estimate these diaphragm forces is proposed for both frame and wall structures. Modern architecture often requires complex floor geometries with long spans leading to stress concentrations, high force demands and potentially large deformations in the diaphragms. There is a lack of guidance and regulation regarding the analysis and design of timber diaphragms and a practical alternative to the simplistic equivalent deep beam analysis or costly finite element modelling is required. An Equivalent Truss Method for the analysis of both light timber framed and massive timber diaphragms is proposed, based on analytical formulations and verified against finite element models. With this method the panel unit shear forces (shear flow) and therefore the fastener demand, chord forces and reaction forces can be evaluated. Because the panel stiffness and fastener stiffness are accounted for, diaphragm deflection, torsional effects and transfer forces can also be assessed. The proposed analysis method is intuitive and can be used with basic analysis software. If required, it can easily be adapted for the use with diaphragms working in the non-linear range. Damage to floor diaphragms resulting from displacement incompatibilities due to frame elongation or out-of plane deformation of walls can compromise the transfer of inertial forces to the lateral load resisting system as well as the stability of other structural elements. Two post-tensioned timber frame structures under quasi-static cyclic and dynamic load, respectively, were tested with different diaphragm panel layouts and connections investigating their ability to accommodate frame elongations. Additionally, a post-tensioned timber wall was loaded under horizontal cyclic loads through two pairs of collector beams. Several different connection details between the wall and the beams were tested, and no damage to the collector beams or connections was observed in any of the tests. To evaluate the increased strength and stiffness due to the wall-beam interaction an analytical procedure is presented. Finally, a timber staircase core was tested under bi-directional loading. Different connection details were used to study the effect of displacement incompatibilities between the orthogonal collector beams. These experiments showed that floor damage due to displacement incompatibilities can be prevented, even with high levels of lateral drift, by the flexibility of well-designed connections and the flexibility of the timber elements. It can be concluded that the flexibility of timber members and the flexibility of their connections play a major role in the behaviour of timber buildings in general and of diaphragms specifically under seismic loads. The increased flexibility enhances higher mode effects and alters the diaphragm force demand. Simple methods are provided to account for this effect on the storey shear, moment and drift demands as well as the diaphragm force demands. The analysis of light timber framing and massive timber diaphragms can be successfully analysed with an Equivalent Truss Method, which is calibrated by accounting for the panel shear and fastener stiffnesses. Finally, displacement incompatibilities in frame and wall structures can be accommodated by the flexibilities of the diaphragm panels and relative connections. A design recommendations chapter summarizes all findings and allows a designer to estimate diaphragm forces, to analyse the force path in timber diaphragms and to detail the connections to allow for displacement incompatibilities in multi-storey timber buildings.

Images, eqnz.chch.2010

20111230_7222_1D3-70 New Brighton Further damage to the bank following the two quakes on 23/12/11. The sewer line broke here and was repaired (patched) by council staff on Christmas Eve. It is hard to beleve that this rock wall was level with the land here, before any of the quakes. #2004

Images, eqnz.chch.2010

The Old Lyttelton Post Office, opened in 1874, showing damage after a series of earthquakes hit Christchurch and Lyttelton over the last 9 months. In the shadow of a broken house, Down a deserted street, Propt walls, cold hearths, and phantom stairs, And the silence of dead feet — Locked wildly in one another's arms I saw two lovers meet. ...

Images, UC QuakeStudies

Bricks have fallen from the walls of the former Princess Cinema in New Brighton, exposing the interior. The photographer comments, "Back of the old Princess Cinema in New Brighton after the earthquake in Christchurch, New Zealand on 22 February. In this picture you can see inside the old cinema curtains. This building has now been knocked down as it was so dangerous".

Images, eqnz.chch.2010

There are occasional sewerage spills into the Avon River while all the sewer and road repairs are carried out. This rock wall was level and well above high tide level prior to the eathquakes. All the houses that can been seen here (except for those on the distant Port Hills) are in the suburban "red zone" and are still to be demolished.

Images, eqnz.chch.2010

Low tide on the Avon River at New Brighton/Bexley. Note the original bank and the rock wall slipage on right. The white additions were added in March and April 2011 to protect the properties behind from flooding. Ultimately this area was "red zoned" with all houses removed or to be removed and the ground left till a rehabilitation method can ...

Images, eqnz.chch.2010

The Cathedral of the Blessed Sacrament, Christcurch, after the 6.3 magnitude quake on 22 February 2011. When The Angels Fall Take your father's cross Gently from the wall A shadow still remaining See the churches fall In mighty arcs of sound And all that they're containing Yet all the rugged souls Looking for their lost homes Shuffle to...

Images, UC QuakeStudies

A photograph of graffiti on one of the walls of the kitchen in Donna Allfrey's house at 406 Oxford Terrace. Parts of the graffiti read, "Quakes, a national disaster", "Recovery, a national disgrace", "Ring fn EQC, ring fn insurance", "Useless fn council", "Don't let the bastards get you down", "Avon Loop - park or developers fodder?", and "Never trust a Carter". There are also shopping and to-do lists scrawled amongst these messages.

Images, UC QuakeStudies

A photograph of the earthquake damage to a section of Robin Duff's house at 386 Oxford Terrace. The chimney has fallen off the roof and is now resting in the patio. Behind the chimney, one of the walls has a noticeable lean and the glass of one of the French doors is broken. The photographer comments, "The glass was broken by looters who entered the house and took bits that interested them".

Images, UC QuakeStudies

Detail of damage to the former Princess Cinema in New Brighton. Bricks have fallen from the wall, exposing the interior. The photographer comments, "This is the back of the old Princess Cinema in New Brighton after the earthquake in Christchurch, New Zealand on 22 February. The bricks seem to be just on the edge of falling. This building has now been knocked down as it was so dangerous".

Images, UC QuakeStudies

Broken stained glass in a window of the ChristChurch Cathedral. The photographer comments, "I only managed to get one picture of the badly earthquake damaged Christchurch Cathedral and I did not want to get the buttresses holding it up like some Medieval siege engine, so I thought this one was perfect. Looking through the window notice that the adjacent wall has gone and the blue windows belong to an office block across the road".

Images, UC QuakeStudies

Damage to TJ's Kazbah in New Brighton. The east and north walls and part of the upper floor have collapsed, tipping rubble and the contents of the rooms out onto the street. The photographer comments, "The occupants of the business and rooms all managed to escape alive. A digger was used to make the building safe and then used to sift through the rubble for any surviving belongings. It was a very emotional time for the ex-occupants".

Research papers, University of Canterbury Library

Drywalls are the typical infill or partitions used in new structures. They are usually located within structural frames and/or between upper and lower floor slabs in buildings. Due to the materials used in their construction, unlike masonry blocks, they can be considered as light non-structural infill/partition walls. These types of walls are especially popular in New Zealand and the USA. In spite of their popularity, little is known about their in-plane cyclic behaviour when infilled within a structural frame. The cause of this lack of knowledge can be attributed to the typical assumption that they are weak non-structural elements and are not expected to interact with the surrounding structural system significantly. However, recent earthquakes have repeatedly shown that drywalls interact with the structure and suffer severe damage at very low drift levels. In this paper, experimental test results of two typical drywall types (steel and timber framed) are reported in order to gather further information on; i) their reverse cyclic behaviour, ii) inter-storey drift levels at which they suffer different levels of damage, iii) the level of interaction with the surrounding structural frame system. The drywall specimens were tested using quasi-static reverse cyclic testing protocols within a full scale precast RC frame at the Structures Laboratory of the University of Canterbury.

Images, Alexander Turnbull Library

The cartoon depicts a rose window set in a stone wall. The glass circles each contain a dollar sign. Refers to the future of the Christchurch Cathedral after the Canterbury earthquakes of 2010 and 2011. The Anglican Church seemed to only consider the money in arguing that it would be too expensive to be repaired or rebuilt. Title from file name Quantity: 1 digital cartoon(s).

Videos, UC QuakeStudies

A video of an interview with Laurence Mote about the wall of containers in Sumner. Shipping containers line the south side of Main Road in Sumner, protecting road users from potential rock fall from the cliffs above. Mote bikes past the containers every day on his way to work. He talks about the risks facing cyclists along Main Road and in greater Christchurch, including pot holes and narrow roads. He advises cyclists to wear bright clothing and lights, and for cars to slow down and give cyclists room.

Images, UC QuakeStudies

Damage to TJ's Kazbah in New Brighton. The east and north walls and part of the upper floor have collapsed, tipping rubble and the contents of the rooms out onto the street. The photographer comments, "The occupants of the business and rooms all managed to escape alive. A digger was used to make the building safe and then used to sift through the rubble for any surviving belongings. It was a very emotional time for the ex-occupants".

Images, UC QuakeStudies

A badly damaged house in Burwood. Parts of the house have moved in different directions, leaving walls and doors misaligned. The photographer comments, "Although this looks like an extreme wide angle shot it is actually a house tilted in every direction at the same time. The earthquake caused the ground to vibrate and compress so much that the sandy soil liquefied and caused the ground to collapse under this modern home".

Research papers, University of Canterbury Library

The University of Canterbury has initialized a research program focusing on the seismic sustainability of structures. As part of this program, the relative seismic sustainability of various structures will be assessed to identify those with the highest sustainability for the Christchurch rebuild and general use in New Zealand. This preliminary case study assesses one reinforced concrete (RC) frame structure and one RC wall structure. The scenario loss is evaluated for two earthquake records considering direct losses only in order to explain and illustrate the methodology.

Research papers, University of Canterbury Library

Low Damage Seismic Design (LDSD) guidance material being developed by Engineering NZ is considering a design drift limit for multi-storey buildings of 0.5% at a new damage control limit state (DCLS). The impact of this new design requirement on the expected annual loss due to repair costs is investigated for a four-storey office building with reinforced concrete walls located in Christchurch. The LDSD guidance material aims to reduce the expected annual loss of complying buildings to below 0.1% of building replacement cost. The research tested this expectation. Losses were estimated in accordance with FEMA P58, using building responses from non-linear time history analyses (performed with OpenSees using lumped plasticity models). The equivalent static method, in line with NZS 1170.5 and NZS 3101, was used to design the building to LDSD specifications, representing a future state-of-practice design. The building designed to low-damage specification returned an expected annual loss of 0.10%, and the building designed conventionally returned an expected annual loss of 0.13%. Limitations with the NZS 3101 method for determining wall stiffness were identified, and a different method acknowledging the relationship between strength and stiffness was used to redesign the building. Along with improving this design assumption, the study finds that LDSD design criteria could be an effective way of limiting damage and losses.

Images, Alexander Turnbull Library

A woman chats over her garden wall to a passerby who is curious about a huge container-like structure labeled 'emergency kit' that has been built beside the house. She says that in the event of a natural disaster Harold wants to ensure that they will have enough provisions to see them through the Rugby World Cup. Refers to the Christchurch earthquake that occurred 4th September 2010. Quantity: 1 digital cartoon(s).

Audio, Radio New Zealand

After years of disruption caused by the Christchurch earthquakes, two schools have finally started moving into their new state of the art facilities. Avonside Girls' High School and Shirley Boys' High School have begun moving students into their new shared but separate campus on the grounds of the old QEII Park in north New Brighton. Some of the features include, a moveable gym, bike stands with spanners and air pumps, and a rock climbing wall. It will be the first time in New Zealand two single-sex schools have been on the same site. Guyon Espiner speaks to Avonside Girls' High principal Sue Hume and Shirley Boys' High School principal John Laurenson.

Images, UC QuakeStudies

A photograph of graffiti on one of the walls of the kitchen in Donna Allfrey's house at 406 Oxford Terrace. Parts of the graffiti read, "Quakes, a national disaster", "Recovery, a national disgrace", "'It's been a lot of fun' - John Key, yeah right!", "Brownlee sucks, "Ring fn EQC, ring fn insurance", "Useless fn council", "Sideshow Bob is an idiot", "Don't let the bastards get you down", "Avon Loop - park or developers fodder?", and "Never trust a Carter". There are also shopping and to-do lists scrawled amongst these messages.