Rapid, accurate structural health monitoring (SHM) assesses damage to optimise decision-making. Many SHM methods are designed to track nonlinear stiffness changes as damage. However, highly nonlinear pinched hysteretic systems are problematic in SHM. Model-based SHM often fails as any mismatch between model and measured response dynamics leads to significant error. Thus, modelfree methods of hysteresis loop tracking methods have emerged. This study compares the robustness and accuracy in the presence of significant measurement noise of the proven hysteresis loop analysis (HLA) SHM method with 3 emerging model-free methods and 2 further novel adaptations of these methods using a highly nonlinear, 6-story numerical structure to provide a known ground-truth. Mean absolute errors in identifying a known nonlinear stiffness trajectory assessed at four points over two successive ground motion inputs from September 2010 and February 2011 in Christchurch range from 1.71-10.52%. However, the variability is far wider with maximum errors ranging from 3.90-49.72%, where the second largest maximum absolute error was still 19.74%. The lowest mean and maximum absolute errors were for the HLA method. The next best method had mean absolute error of 2.92% and a maximum of 10.51%. These results show the clear superiority of the HLA method over all current emerging model-free methods designed to manage the highly nonlinear pinching responses common in reinforced concrete structures. These results, combined with high robustness and accuracy in scaled and fullscale experimental studies, provide further validation for using HLA for practical implementation.
Our managed isolation hotels are too posh and returnees should not be treated like hotel guests with luxuries like free menu choices and drycleaning. That's the verdict from New Zealand woman Toni Foster who has returned to the country to take up a job and has spent the past 11 days in isolation at Ellerslie's Novotel Hotel. Toni says she had expected to return to isolation in accommodation similar to the container village after the Christchurch earthquakes - not a free four or five star hotel which she said some returnees were treating as a holiday. She says returnees should not be treated like hotel guests because they're not paying a cent to be there.
This research investigates creativity in a post-disaster setting. The data explore creativity at the intersection of the affected community of Christchurch, New Zealand and the social processes that followed the earthquakes of 2010 - 2012. Personal and contextual influences on creative ideas implemented for community or commercial benefit are also examined.
Viewed as creative, unique approaches to post-disaster problem solving were celebrated locally, nationally and internationally (Bergman, 2014; Wesener, 2015; Cloke & Conradson, 2018). Much has been written about creativity, particularly creativity in organisations and in business. However, little is known with regards to who creates after a disaster, why individuals choose to do so and what impact the post-disaster context has on their creative activity. This exploratory study draws on the literature from the fields of creativity, disasters, psychology, sociology and entrepreneurship to interpret first-hand accounts of people who acted on creative ideas in a physically and socially altered environment.
A mixed method - albeit predominantly qualitative - approach to data gathering was adopted that included interviews (n=45) with participants who had been the primary drivers of creative ideas implemented in Christchurch after September 2010 – the first major (7.1 magnitude) earthquake in a prolonged sequence of thousands of aftershocks.
Key findings include that a specific type of creativity results from the ‘collision’ between individuals and social processes activated by a disaster situation. This type of creativity could be best categorised as ‘little c’ or socially adaptive and emerges through a prosocial filter. There is wide consensus amongst creativity researchers - principally social psychologists - that for output to be considered creative it must be both novel and useful (Runco & Jaegar, 2012). There is greater tolerance for the novelty component after a disaster as novelty itself has greater utility, either as a distraction or because alternatives are few. Existing creativity models show context as input – an additional component of the creative process – but after a disaster the event itself becomes the catalyst for social processes that result in the creativity seen. Most participants demonstrated characteristics commonly associated with creativity and could be categorised as either a ‘free thinker’ and/or an ‘opportunist’. Some appear preadapted to create and thrive in unstable circumstances.
Findings from participants’ completion of a Ten Item Personality Inventory (TIPI) showed an apparent reduced need for extraversion in relation to implementing creative ventures in society. This factor, along with higher levels of agreeableness may indicate a potentially detrimental effect on the success of creative ideas established after a disaster, despite earnest intentions.
Three new models are presented to illustrate the key findings of this study. The models imply that disasters enhance both the perceived value of creativity and the desire to act creatively for prosocial ends. The models also indicate that these disaster influenced changes are likely to be temporary.
