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Research papers, University of Canterbury Library

A seismic financial risk analysis of typical New Zealand reinforced concrete buildings constructed with topped precast concrete hollow-core units is performed on the basis of experimental research undertaken at the University of Canterbury over the last five years. An extensive study that examines seismic demands on a variety of multi-storey RC buildings is described and supplemented by the experimental results to determine the inter-storey drift capacities of the buildings. Results of a full-scale precast concrete super-assemblage constructed and tested in the laboratory in two stages are used. The first stage investigates existing construction and demonstrates major shortcomings in construction practice that would lead to very poor seismic performance. The second stage examines the performance of the details provided by Amendment No. 3 to the New Zealand Concrete Design Code NZS 3101:1995. This paper uses a probabilistic financial risk assessment framework to estimate the expected annual loss (EAL) from previously developed fragility curves of RC buildings with precast hollow core floors connected to the frames according to the pre-2004 standard and the two connection details recommended in the 2004 amendment. Risks posed by different levels of damage and by earthquakes of different frequencies are examined. The structural performance and financial implications of the three different connection details are compared. The study shows that the improved connection details recommended in the 2004 amendment give a significant economic payback in terms of drastically reduced financial risk, which is also representative of smaller maintenance cost and cheaper insurance premiums.

Research papers, University of Canterbury Library

A three dimensional approximately half scale experimental subassemblage is currently being tested at the University of Canterbury to investigate the effect of precast-prestressed floor units, which do not span past the internal columns, on the seismic performance of reinforced concrete moment resisting frames. This paper reports the preliminary results from the test, with the focus on elongation within the plastic hinges and strength enhancement in the frames. The preliminary results have shown that elongation between the external and internal plastic hinges varies by more than two fold. With the addition of the prestressed floor units, the strength of the moment resisting frame used in the test was found to be 25% higher than the current code specified value. In other situations, particularly where there are more than 2 bays in a moment resisting frame, greater strength enhancement may be expected. Any underestimation of beam strength is undesirable as it may result in the development of nonductile failure modes in a major earthquake.

Images, eqnz.chch.2010

Hotel Grand Chancellor on verge of collapse but still standing after the 6.3 magnitude quake hit Christchurch on 22 February 2011 because of concrete being poured into the lower floors.

Images, UC QuakeStudies

A photograph of a kitchen in the Diabetes Centre. The fridge, dishwater, and several drawers have opened, spilling food and crockery onto the floor. Tea and coffee has fallen off the bench into the dishwasher.

Images, UC QuakeStudies

A photograph of a kitchen in the Diabetes Centre. The fridge, dishwater, and several drawers have opened, spilling food and crockery onto the floor. Tea and coffee has fallen off the bench into the dishwasher.

Research papers, University of Canterbury Library

The seismic response of unreinforced masonry (URM) buildings, in both their as-built or retrofitted configuration, is strongly dependent on the characteristics of wooden floors and, in particular, on their in-plane stiffness and on the quality of wall-to-floor connections. As part of the development of alternative performance-based retrofit strategies for URM buildings, experimental research has been carried out by the authors at the University of Canterbury, in order to distinguish the different elements contributing to the whole diaphragm's stiffness. The results have been compared to the ones predicted through the use of international guidelines in order to highlight shortcomings and qualities and to propose a simplified formulation for the evaluation of the stiffness properties.

Images, UC QuakeStudies

Member of the public using the Dance-O-Mat, a dance floor on a vacant site with coin operated light and music player. This was a project by Gap Filler who wanted to give the Christchurch community a unique dance experience whilst bringing life to our broken city.

Audio, Radio New Zealand

Earthquake bus survivor, Mike Ardagh - Christchurch Hospital, Reporter Erina O'Donohue live from Christchurch, Where to obtain water, Murray McCully thanks international community, Cowles Stadium welfare centre closed, Man escapes from 12th floor of Forsyth Barr building, Aussie medics set up field hospital, Schools need significant rebuilding and Fourteen supermarkets closed in Christchurch.