A preliminary case study assessing the seismic sustainability of two reinforced concrete structures, a frame structure and a wall structure, was conducted to determine which structural system is more seismically sustainable. The two structures were designed to the same standards and were assumed to be located in Christchurch, New Zealand. A component-based probabilistic seismic loss assessment, considering direct losses only, was conducted for two ground motion records, regarded to approximately represent a 1 in 500 year earthquake event and a 1 in 2500 year earthquake event, respectively. It is shown that the wall structure results in lower direct losses than the frame structure in the less severe ground motion scenario. However, in the more severe ground motion scenario, the frame structure results in lower direct losses. Hence, this study demonstrates that which structural system has the lower direct losses depends on the ground motion intensity level.
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.
Utility managers are always looking for appropriate tools to estimate seismic damage in wastewater networks located in earthquake prone areas. Fragility curves, as an appropriate tool, are recommended for seismic vulnerability analysis of buried pipelines, including pressurised and unpressurised networks. Fragility curves are developed in pressurised networks mainly for water networks. Fragility curves are also recommended for seismic analysis in unpressurised networks. Applying fragility curves in unpressurised networks affects accuracy of seismic damage estimation. This study shows limitations of these curves in unpressurised networks. Multiple case study analysis was applied to demonstrate the limitations of the application of fragility curves in unpressurised networks in New Zealand. Four wastewater networks within New Zealand were selected as case studies and various fragility curves used for seismic damage estimation. Observed damage in unpressurised networks after the 2007 earthquake in Gisborne and the 2010 earthquake in Christchurch demonstrate the appropriateness of the applied fragility curves to New Zealand wastewater networks. This study shows that the application of fragility curves, which are developed from pressurised networks, cannot be accurately used for seismic damage assessment in unpressurised wastewater networks. This study demonstrated the effects of different parameters on seismic damage vulnerability of unpressurised networks.
Test results are presented for wall-diaphragm plate anchor connections that were axially loaded to rupture. These connection samples were extracted post-earthquake by sorting through the demolition debris from unreinforced masonry (URM) buildings damaged in the Christchurch earthquakes. Unfortunately the number of samples available for testing was small due to the difficulties associated with sample collection in an environment of continuing aftershocks and extensive demolition activity, when personal safety combined with commercial activity involving large demolition machinery were imperatives that inhibited more extensive sample collection for research purposes. Nevertheless, the presented data is expected to be of assistance to structural engineers undertaking seismic assessment of URM buildings that have existing wall-diaphragm anchor plate connections installed, where it may be necessary to estimate the capacity of the existing connection as an important parameter linked with determining the current seismic capacity of the building and therefore influencing the decision regarding whether supplementary connections should be installed.
During many years the analysis of some geophysical results of Charles Darwin was being carried out in Department. Darwin has connected almost 200 years ago results of catastrophic earthquakes with vertical movement of a surface of the Earth. Usually this movement less horizontal movement and its influence on destruction of cities is not considered. Earthquake hazard assessment studies were focused usually on the horizontal ground motion. Effects of the strong vertical motion were not, practically, discussed. The margins of safety against gravity-induced static vertical forces in constructed buildings usually provide adequate resistance to dynamic forces induced by the vertical acceleration during an earthquake. However, the earthquake in Christchurch is an example of the vertical seismic shock . The earthquake magnitude was rather small - nearby 6.3. However, the result was catastrophic. The same took place in 1835. It allowed to Darwin to formulate a few great ideas. Charles Darwin has explained qualitatively results of an interaction of huge seismic waves with volcanoes and the nature of volcanism and seismicity of our planet. These important data of Charles Darwin became very actual recently. It is possible to tell also the same about tsunami and extreme ocean waves described by Charles Darwin. Therefore this data were analyzed using modern mechanics, mathematics and physics in Department. In particular, the theory of catastrophic waves was developed based on Darwin's data. The theory tried to explain occurrence, evolution and distribution the catastrophic waves in various natural systems, since atoms, oceans, surfaces of the Earth and up to the very early Universe. Some results of the research were published in prestigious magazines. Later they were presented in two books devoted to Charles Darwin's anniversary (2009). Last from them was published in Russian (2011). We give here key ideas of this research which is a part of interdisciplinary researches of Department. Some ideas are discussed. Not less important purpose is very short historical review of some researches of Darwin. In particular, we underline Darwin' priority in the formulation of the bases of Dynamics Earth.
As part of the ‘Project Masonry’ Recovery Project funded by the New Zealand Natural Hazards Research Platform, commencing in March 2011, an international team of researchers was deployed to document and interpret the observed earthquake damage to masonry buildings and to churches as a result of the 22nd February 2011 Christchurch earthquake. The study focused on investigating commonly encountered failure patterns and collapse mechanisms. A brief summary of activities undertaken is presented, detailing the observations that were made on the performance of and the deficiencies that contributed to the damage to approximately 650 inspected unreinforced clay brick masonry (URM) buildings, to 90 unreinforced stone masonry buildings, to 342 reinforced concrete masonry (RCM) buildings, to 112 churches in the Canterbury region, and to just under 1100 residential dwellings having external masonry veneer cladding. Also, details are provided of retrofit techniques that were implemented within relevant Christchurch URM buildings prior to the 22nd February earthquake. In addition to presenting a summary of Project Masonry, the broader research activity at the University of Auckland pertaining to the seismic assessment and improvement of unreinforced masonry buildings is outlined. The purpose of this outline is to provide an overview and bibliography of published literature and to communicate on-going research activity that has not yet been reported in a complete form. http://sesoc.org.nz/conference/programme.pdf
Following the 2010/2011 Canterbury earthquakes a detailed campaign of door to door assessments was conducted in a variety of areas of Christchurch to establish the earthquake performance of residential dwellings having masonry veneer as an external cladding attached to a lightweight timber framing system. Specifically, care was taken to include regions of Christchurch which experienced different levels of earthquake shaking in order to allow comparison between the performance of different systems and different shaking intensities. At the time of the inspections the buildings in the Christchurch region had been repeatedly subjected to large earthquakes, presenting an opportunity for insight into the seismic performance of masonry veneer cladding. In total just under 1100 residential dwellings were inspected throughout the wider Christchurch area, of which 24% were constructed using the older nail-on veneer tie system (prior to 1996) and 76% were constructed using screw fixed ties to comply with the new 1996 standards revision (post-1996), with 30% of all inspected houses being of two storey construction. Of the inspected dwellings 27% had some evidence of liquefaction, ground settlement or lateral spreading. Data such as damage level, damage type, crack widths, level of repair required and other parameters were collected during the survey. A description of the data collection processes and a snapshot of the analysis results are presented within. http://15ibmac.com/home/
