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Research papers, University of Canterbury Library

In recent years, rocking isolation has become an effective approach to improve seismic performance of steel and reinforced concrete structures. These systems can mitigate structural damage through rigid body displacement and thus relatively low requirements for structural ductility, which can significantly improve seismic resilience of structures and reduce repairing costs after strong earthquakes. A number of base rocking structural systems with only a single rocking interface have been proposed. However, these systems can have significant high mode effect for high rise structures due to the single rocking interface. This RObust BUilding SysTem (ROBUST) project is a collaborative China-New Zealand project sponsored by the International Joint Research Laboratory of Earthquake Engineering (ILEE), Tongji University, and a number of agencies and universities within New Zealand including the BRANZ, Comflor, Earthquake Commission, HERA, QuakeCoRE, QuakeCentre, University of Auckland, and the University of Canterbury. A number of structural configurations will be tested [1, 2], and non-structural elements including ceilings, infilling walls, glazed curtain walls, precast concrete panels, piping system will also be tested in this project [3]. Within this study, a multiple rocking column steel structural system was proposed and investigated mainly by Tongji team with assistance of NZ members. The concept of rocking column system initiates from the structure of Chinese ancient wooden pagoda. In some of Chinese wooden pagodas, there are continuous core columns hanged only at the top of each pagoda, which is not connected to each stories. This core column can effectively avoid collapse of the whole structure under large storey drifts. Likewise, there are also central continuous columns in the newly proposed steel rocking column system, which can avoid weak story failure mechanism and make story drifts more uniform. In the proposed rocking column system, the structure can switch between an elastic rigidly connected moment resisting frame and a controlled rocking column system when subjected to strong ground motion excitations. The main seismic energy can be dissipated by asymmetric friction beam–column connections, thereby effectively reducing residual displacement of the structure under seismic loading without causing excessive damage to structural members. Re–centering of the structure is provided not only by gravity load carried by rocking columns, but also by mould coil springs. To investigate dynamic properties of the proposed system under different levels of ground excitations, a full-scale threestory steel rocking column structural system with central continuous columns is to be tested using the International joint research Laboratory of Earthquake Engineering (ILEE) facilities, Shanghai, China and an analytical model is established. A finite element model is also developed using ABAQUS to simulate the structural dynamic responses. The rocking column system proposed in this paper is shown to produce resilient design with quick repair or replacement.

Research papers, University of Canterbury Library

Timber-based hybrid structures provide a prospective solution for utilizing environmentally friendly timber material in the construction of mid-rise or high-rise structures. This study mainly focuses on structural damage evaluation for a type of timber-steel hybrid structures, which incorporate prefabricated light wood frame shear walls into steel moment-resisting frames (SMRFs). The structural damage of such a hybrid structure was evaluated through shake table tests on a four-story large-scale timber-steel hybrid structure. Four ground motion records (i.e., Wenchuan earthquake, Canterbury earthquake, El-Centro earthquake, and Kobe earthquake) were chosen for the tests, with the consideration of three different probability levels (i.e., minor, moderate and major earthquakes) for each record. During the shake table tests, the hybrid structure performed quite well with visual damage only to wood shear walls. No visual damage in SMRF and the frame-to-wall connections was observed. The correlation of visual damage to seismic intensity, modal-based damage index and inter-story drift was discussed. The reported work provided a basis of knowledge for performance-based seismic design (PBSD) for such timber-based hybrid structures.

Images, UC QuakeStudies

A digitally manipulated image of furniture and machinery. The photographer comments, "This furniture restoration company got caught in the middle of the Christchurch earthquake and lost a whole wall. After constant exposure to the elements everything now needs a bit of restoration. They are now working in a different part of Christchurch, but their past can still be seen".

Research papers, University of Canterbury Library

In order to provide information related to seismic vulnerability of non-ductile reinforced concrete (RC) frame buildings, and as a complementary investigation on innovative feasible retrofit solutions developed in the past six years at the University of Canterbury on pre-19170 reinforced concrete buildings, a frame building representative of older construction practice was tested on the shake table. The specimen, 1/2.5 scale, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. The as-built (benchmark) specimen was first tested under increasing ground motion amplitudes using records from Loma Prieta Earthquake (California, 1989) and suffered significant damage at the upper floor, most of it due to lap splices failure. As a consequence, in a second stage, the specimen was repaired and modified by removing the concrete in the lap splice region, welding the column longitudinal bars, replacing the removed concrete with structural mortar, and injecting cracks with epoxy resin. The modified as-built specimen was then tested using data recorded during Darfield (New Zealand, 2010) and Maule (Chile, 2010) Earthquakes, with whom the specimen showed remarkably different responses attributed to the main variation in frequency content and duration. In this contribution, the seismic performance of the three series of experiments are presented and compared.

Images, Alexander Turnbull Library

Three men chat in a pub. One of them reads a newspaper article about the Mayor of Christchurch, Bob Parker, who commented that he was scared of earthquakes when in Wellington. All three drinkers would rather be in Wellington than trapped beside Bob Parker at a dinner table. Context: Christchurch's Mayor has told the Emergency Management Conference he's scared to be in Wellington. He gave graphic descriptions of the Christchurch earthquakes, getting people to bang on the tables for 45 seconds so they could see what it felt like. Quantity: 1 digital cartoon(s).

Images, UC QuakeStudies

Members of the Shirley community relaxing around a table set up by the World Mission Society Church of God on North Parade in Shirley. A member of the church can be seen holding a sign advertising free sausages.

Images, UC QuakeStudies

Volunteers distributing care packages to affected residents at a Red Cross aid station on Pages Road. A sign in front of the table reads "Free". Next to them, a man sanitises his hands at a water suppy point.

Images, UC QuakeStudies

A photograph of members of the Red Cross at the Registration table in Cowles Stadium on Pages Road. The stadium was set up by Civil Defence as temporary accommodation for citizens displayed by the 4 September 2010 earthquake.

Images, UC QuakeStudies

A photograph of the intersection of Lichfield, Manchester, and High Streets, taken from the corner of Lichfield and High Streets. Emergency management personnel are crossing the intersection. To the right an excavator is parked on Manchester Street in front of the rubble from a demolished building. In the background the ANZ Building has been partially demolished and an excavator is sitting in front. To the right of the excavator there are several chairs, tables, and a couch under a red umbrella. Another member of an emergency management team is sitting on the couch.

Research papers, University of Canterbury Library

It is fast becoming common practice for civil engineering infrastructure and building structures to be designed to achieve a set of performance objectives. To do so, consideration is now being given to systems capable of sustaining minimal damage after an earthquake while still being cost competitive. This has led to the development of high performance seismic resisting systems, followed by advances in design methodologies. The paper presents the experimental response of four pre-cast, post-tensioned rocking walls with high-performing dissipating solutions tested on the shake-table at the University of Canterbury. The wall systems were designed as a retrofit solution for an existing frame building however, can also be used for the design of new, high-performance structures. The use of externally mounted dampers allowed numerous dissipation schemes to be explored including mild-steel dampers (hysteretic dampers), viscous dampers, a combination of both or no dampers. The advantages of both velocity and displacement dependant dissipation was investigated for protection against strong ground motions with differing rupture characteristics i.e. far-field and near-field events. The experimental results are used to verify a proposed design procedure for post-tensioned rocking systems with supplementary hysteretic and viscous dissipation. The predicted response compared well with the measured shake-table response.

Images, UC QuakeStudies

A photograph of workers preparing breakfast for the emergency management personnel in Latimer Square. The workers are wearing high-visibility vests and hair nets. A sign on one of the tent poles reads, "Please wash hand before approaching the food tables, thank you".

Images, UC QuakeStudies

A photograph of emergency management personnel walking down New Regent Street towards the intersection of Armagh Street. Pavers along either side of the tramline have risen and shifted out of place. Many tables and chairs from cafes and restaurants are still sitting outside.

Images, UC QuakeStudies

A photograph of participants signing in at the registration table for Milk Fight - a dairy-fuelled urban food fight by local artist Gaby Montego. The event was part of FESTA 2014. Milk Fight was held on the former Convention Centre site at 100 Peterborough Street.