The objective of this project is to collect perishable seismic response data from the baseisolated Christchurch Women's Hospital. The strong and continuing sequence of aftershocks presents a unique opportunity to capture high-fidelity data from a modern base-isolated facility. These measurements will provide quantitative information required to assess the mechanisms at play in this and in many other seismically-isolated structures.
The performance of conventionally designed reinforced concrete (RC) structures during the 2011 Christchurch earthquake has demonstrated that there is greater uncertainty in the seismic performance of RC components than previously understood. RC frame and wall structures in the Christchurch central business district were observed to form undesirable cracks patterns in the plastic hinge region while yield penetration either side of cracks, and into development zones, were less than theoretical predictions. The implications of this unexpected behaviour: (i) significantly less available ductility; (ii) less hysteretic energy dissipation; and (iii) the localization of peak reinforcement strains, results in considerable doubt for the residual capacity of RC structures. The significance of these consequences has prompted a review of potential sources of uncertainty in seismic experimentation with the intention to improve the current confidence level for newly designed conventional RC structures. This paper attempts to revisit the principles of RC mechanics, in particular, to consider the influence of loading history, concrete tensile strength, and reinforcement ratio on the performance of ‘real’ RC structures compared to experimental test specimens.
Children are often overlooked in the aftermath of a natural disaster, and children’s use of coping strategies plays an important part in their post-disaster adaptation (Vernberg, La Greca, Silverman, & Prinstein, 1996). The aim of this qualitative study was to explore the coping strategies of children with adequate self-regulation skills and minimal behaviour problems, living in Christchurch following the major 2010 and 2011 earthquakes. This aim was achieved through the use of semi-structured interviews with five seven-year-old children, their parents, and their teachers. These interviews were analysed using Directed Content Analysis and results showed that children most often reported using active and adaptive coping strategies, followed by avoidant strategies. Results in the current literature regarding children’s coping suggest that children exposed to natural disasters are able to utilise strategies that involve some personal control over their environment and emotions, through the use of active and adaptive coping strategies. Findings from this study contribute to the current understanding of children’s use of coping strategies when faced with commonly occurring childhood upsets. Further research is required regarding the outcomes associated with the use of effective coping strategies following traumatic events.
Following the 2010-2011 Canterbury (New Zealand) earthquake sequence, lightly reinforced wall structures in the Christchurch central business district were observed to form undesirable crack patterns in the plastic hinge region, while yield penetration either side of cracks and into development zones was less than predicted using empirical expressions. To some extent this structural behaviour was unexpected and has therefore demonstrated that there may be less confidence in the seismic performance of conventionally designed reinforced concrete (RC) structures than previously anticipated. This paper provides an observation-based comparison between the behaviour of RC structural components in laboratory testing and the unexpected structural behaviour of some case study buildings in Christchurch that formed concentrated inelastic deformations. The unexpected behaviour and poor overall seismic performance of ‘real’ buildings (compared to the behaviour of laboratory test specimens) was due to the localization of peak inelastic strains, which in some cases has arguably led to: (i) significantly less ductility capacity; (ii) less hysteretic energy dissipation; and (iii) the fracture of the longitudinal reinforcement. These observations have raised concerns about whether lightly reinforced wall structures can satisfy the performance objective of “Life Safety” at the Ultimate Limit State. The significance of these issues and potential consequences has prompted a review of potential problems with the testing conditions and procedures that are commonly used in seismic experimentations on RC structures. This paper attempts to revisit the principles of RC mechanics, in particular, the influence of loading history, concrete tensile strength, and the quantity of longitudinal reinforcement on the performance of real RC structures. Consideration of these issues in future research on the seismic performance of RC might improve the current confidence levels in newly designed conventional RC structures.
Despite their good performance in terms of their design objectives, many modern code-prescriptive buildings built in Christchurch, New Zealand had to be razed after the 2010-2011 Canterbury earthquakes because repairs were deemed too costly due to widespread sacrificial damage. Clearly a more effective design paradigm is needed to create more resilient structures. Rocking, post-tensioned connections with supplemental energy dissipation can contribute to a damage avoidance designs (DAD). However, few have achieved all three key design objectives of damage-resistant rocking, inherent recentering ability, and repeatable, damage-free energy dissipation for all cycles, which together offer a response which is independent of loading history. Results of experimental tests are presented for a near full-scale rocking beam-column sub-assemblage. A matrix of test results is presented for the system under varying levels of posttensioning, with and without supplemental dampers. Importantly, this parametric study delineates each contribution to response. Practical limitations on posttensioning are identified: a minimum to ensure static structural re-centering, and a maximum to ensure deformability without threadbar yielding. Good agreement between a mechanistic model and experimental results over all parameters and inputs indicates the model is robust and accurate for design. The overall results indicate that it is possible to create a DAD connection where the non-linear force-deformation response is loading history independent and repeatable over numerous loading cycles, without damage, creating the opportunity for the design and implementation of highly resilient structures.
A major lesson from the 2011 Christchurch earthquake was the apparent lack of ductility of some lightly reinforced concrete (RC) wall structures. In particular, the structural behaviour of the critical wall in the Gallery Apartments building demonstrated that the inelastic deformation capacity of a structure, as well as potentially brittle failure of the reinforcement, is dependent on the level of bond deterioration between reinforcement and surrounding concrete that occurs under seismic loading. This paper presents the findings of an experimental study on bond behaviour between deformed reinforcing bars and the surrounding concrete. Bond strength and relative bond slip was evaluated using 75 pull-out tests under monotonic and cyclic loading. Variations of the experiments include the loading rate, loading history, concrete strength (25 to 70 MPa), concrete age, cover thickness, bar diameter (16 and 20 mm), embedded length, and the position of the embedded bond region within the specimen (deep within or close to free surface). Select test results are presented with inferred implications for RC structures.
Existing New Zealand (NZ) building stock contains a significant number of structures designed prior to 1995 with non-ductile reinforced concrete (RC) columns. Recent earthquakes and research show that columns with such details perform poorly when subjected to seismic demand, losing gravity load carrying capacity at drift levels lower than the expected one. Therefore, in order to have a better understanding of existing RC columns in NZ, the history of these elements is investigated in this paper. The evolution of RC column design guidelines in NZ standards since the 1970s is scrutinized. For this purpose, a number of RC columns from Christchurch buildings built prior to 1995 are assessed using the current code of practice.
This paper presents preliminary results of an experimental campaign on three beam-column joint subassemblies extracted from a 22-storey reinforced concrete frame building constructed in late 1980s at the Christchurch’s Central Business District (CBD) area, damaged and demolished after the 2010-2011 Canterbury earthquakes sequence (CES). The building was designed following capacity design principles. Column sway (i.e., soft storey) mechanisms were avoided, and the beams were provided with plastic hinge relocation details at both beam-ends, aiming at developing plastic hinges away from the column faces. The specimens were tested under quasi-static cyclic displacement controlled lateral loading. One of the specimens, showing no visible residual cracks was cyclically tested in its as-is condition. The other two specimens which showed residual cracks varying between hairline and 1.0mm in width, were subjected to cyclic loading to simulate cracking patterns consistent with what can be considered moderate damage. The cracked specimens were then repaired with an epoxy injection technique and subsequently retested until reaching failure. The epoxy injection techniques demonstrated to be quite efficient in partly, although not fully, restoring the energy dissipation capacities of the damaged specimens at all beam rotation levels. The stiffness was partly restored within the elastic range and almost fully restored after the onset of nonlinear behaviour.
This work investigates the possibility of developing a non-contact, non-line of sight sensor to measure interstorey drift through simulation and experimental validation. • The method uses frequency-modulated continuous wave (FMCW) radar to measure displacement. This method is commonly in use in a number of modern applications, including aircraft altimeters and automotive parking sensors. • The technique avoids numerous problems found in contemporary structural health monitoring methods, namely integral drift errors and structural modification requirements. • The smallest achievable detection error in displacement was found to be as low as 0.26%, through simulated against the displacement response of a single degree of freedom structure subject to ground motion excitation. • This was verified during experimentation, when a corner-style reflector was placed on a shake table running ground motion data taken from the 4th September 2010 earthquake in Christchurch. These results confirmed the conclusions drawn from simulation.
© 2018 Springer Nature B.V. This study compares seismic losses considering initial construction costs and direct-repair costs for New Zealand steel moment-resisting frame buildings with friction connections and those with extended bolted-end-plate connections. A total of 12 buildings have been designed and analysed considering both connection types, two building heights (4-storey and 12-storey), and three locations around New Zealand (Auckland, Christchurch, and Wellington). It was found that buildings with friction connections required design to a higher design ductility, yet are generally stiffer due to larger beams being required to satisfy higher connection overstrength requirements. This resulted in the frames with friction connections experiencing lower interstorey drifts on most floors but similar peak total floor accelerations, and subsequently incurring lower drift-related seismic repair losses. Frames with friction connections tended to have lower expected net-present-costs within 50 years of the building being in service for shorter buildings and/or if located in regions of high seismicity. None of the frames with friction connections in Auckland showed any benefits due to the low seismicity of the region.
Observations of out-of-plane (OOP) instability in the 2010 Chile earthquake and in the 2011 Christchurch earthquake resulted in concerns about the current design provisions of structural walls. This mode of failure was previously observed in the experimental response of some wall specimens subjected to in-plane loading. Therefore, the postulations proposed for prediction of the limit states corresponding to OOP instability of rectangular walls are generally based on stability analysis under in-plane loading only. These approaches address stability of a cracked wall section when subjected to compression, thereby considering the level of residual strain developed in the reinforcement as the parameter that prevents timely crack closure of the wall section and induces stability failure. The New Zealand code requirements addressing the OOP instability of structural walls are based on the assumptions used in the literature and the analytical methods proposed for mathematical determination of the critical strain values. In this study, a parametric study is conducted using a numerical model capable of simulating OOP instability of rectangular walls to evaluate sensitivity of the OOP response of rectangular walls to variation of different parameters identified to be governing this failure mechanism. The effects of wall slenderness (unsupported height-to-thickness) ratio, longitudinal reinforcement ratio of the boundary regions and length on the OOP response of walls are evaluated. A clear trend was observed regarding the influence of these parameters on the initiation of OOP displacement, based on which simple equations are proposed for prediction of OOP instability in rectangular walls.
Recent earthquakes in New Zealand proved that a shift is necessary in the current design practice of structures to achieve better seismic performance. Following such events, the number of new buildings using innovative technical solutions (e.g. base isolation, controlled rocking systems, damping devices, etc.), has increased, especially in Christchurch. However, the application of these innovative technologies is often restricted to medium-high rise buildings due to the maximum benefit to cost ratio. In this context, to address this issue, a multi-disciplinary geo-structural-environmental engineering project funded by the Ministry of Business Innovation and Employment (MBIE) is being carried out at the University of Canterbury. The project aims at developing a foundation system which will improve the seismic performance of medium-density low-rise buildings. Such foundation is characterized by two main elements: 1) granulated tyre rubber mixed with gravelly soils to be placed beneath the structure, with the goal of damping part of the seismic energy before it reaches the superstructure; and 2) a basement raft made of steel-fibre rubberised concrete to enhance the flexibility of the foundation under differential displacement demand. In the first part of this paper, the overarching objectives, scope and methodology of the project will be briefly described. Then, preliminary findings on the materials characterization, i.e., the gravel-rubber mixtures and steel-fibre rubberised concrete mixes, will be presented and discussed with focus on the mechanical behaviour.
One of the failure modes that got the attention of researchers in the 2011 February New Zealand earthquake was the collapse of a key supporting structural wall of Grand Chancellor Hotel in Christchurch which failed in a brittle manner. However, until now this failure mode has been still a bit of a mystery for the researchers in the field of structural engineering. Moreover, there is no method to identify, assess and design the walls prone to such failure mode. Following the recent break through regarding the mechanism of this failure mode based on experimental observations (out-of-plane shear failure), a numerical model that can capture this failure was developed using the FE software DIANA. A comprehensive numerical parametric study was conducted to identify the key parameters contributing to the development of out-of-plane shear failure in reinforced concrete (RC) walls. Based on the earthquake observations, experimental and numerical studies conducted by the authors of this paper, an analytical method to identify walls prone to out-of-plane shear failure that can be used in practice by engineers is proposed. The method is developed based on the key parameters affecting the seismic performance of RC walls prone to out-of-plane shear failure and can be used for both design and assessment purposes
The earthquake engineering community is currently grappling with the need to improve the post-earthquake reparability of buildings. As part of this, proposals exist to change design criteria for the serviceability limit state (SLS). This paper reviews options for change and considers how these could impact the expected repair costs for typical New Zealand buildings. The expected annual loss (EAL) is selected as a relevant measure or repair costs and performance because (i) EAL provides information on the performance of a building considering a range of intensity levels, (ii) the insurance industry refers to EAL when setting premiums, and (iii) monetary losses are likely to be correlated with loss of building functionality. The paper argues that because the expected annual loss is affected by building performance over a range of intensity levels, the definition of SLS criteria alone may be insufficient to effectively limit losses. However, it is also explained that losses could be limited effectively if the loadings standard were to set the SLS design intensity considering the potential implications on EAL. It is shown that in order to achieve similar values of EAL in Wellington and Christchurch, the return period intensity for SLS design would need to be higher in Christchurch owing to differences in local hazard conditions. The observations made herein are based on a simplified procedure for EAL estimation and hence future research should aim to verify the findings using a detailed loss assessment approach applied to a broad range of case study buildings.
Following the recent earthquakes in Chile (2010) and New Zealand (2010/2011), peculiar failure modes were observed in Reinforced Concrete (RC) walls. These observations have raised a global concern on the contribution of bi-directional loading to these failure mechanisms. One of the failure modes that could potentially result from bidirectional excitations is out-of-plane shear failure. In this paper an overview of the recent experimental and numerical findings regarding out-of-plane shear failure in RC walls are presented. The numerical study presents the Finite Element (FE) simulation of wall D5-6 from the Grand Chancellor Hotel that failed in shear in the out-of-plane direction in the February 2011 Christchurch earthquake. The main objective of the numerical study was to investigate the reasons for this failure mode. The experimental campaign includes the recent experiments conducted in the Structural Engineering Laboratory of the University of Canterbury. The experimental study included three rectangular slender RC walls designed based on NZS3101: 2006-A3 (2017) for three different ductility levels, namely: nominally ductile, limited ductile and ductile. The numerical results showed that high axial load combined with bi-directional loading caused the out-of-plane shear failure in wall D5-6 from the Grand Chancellor Hotel. This was also confirmed and further investigated in the experimental phase of the study.
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.
In this paper, we consider how religious leaders and Civil Defence authorities might collaborate to establish a two-way information conduit during the aftermath of a disaster. Using surveys and in-person interviews, clergy in different Christian denominations were asked about their roles in the earthquake, the needs of their congregations and the possibilities and obstacles to deeper collaboration with Civil Defence authorities.
As a result of the Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. Experience from 2010 Chile indicates that it is possible to repair severely damaged concrete elements (see photo at right), although limited testing has been performed on such repaired components. The first phase of this project is focused on the performance of two lightly-reinforced concrete walls that are being repaired and re-tested after damage sustained during previous testing.
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The current seismic design practice for reinforced concrete (RC) walls has been drawn into question following the unsatisfactory performance of several RC wall buildings during the Canterbury earthquakes. An overview of current research being undertaken at the University of Auckland into the seismic behaviour of RC walls is presented. The main objectives of this research project are to understand the observed performance of RC walls in Christchurch, quantify the seismic loads on RC walls, and developed improved design procedures for RC walls that will assist in revisions to the New Zealand Concrete Structures Standard. A database summarising the performance of RC wall buildings in the Christchurch CBD was collated to identify damage modes and case-study buildings. A detailed investigation is underway to verify the seismic performance of lightly reinforced concrete walls and initial numerical modeling and small-scale tests are presented in addition to details of planned experimental tests of RC walls. Numerical modelling is being used to understand the potential influence that interactions between walls and other structural elements have on the seismic response of buildings and the loads generated on RC walls. The results from finite element analysis of a severely damaged RC wall in Christchurch highlighted the effect that the floor diaphragms have on the distribution of shear stains in the wall.
Unreinforced masonry (URM) is a construction type that was commonly adopted in New Zealand between the 1880s and 1930s. URM construction is evidently vulnerable to high magnitude earthquakes, with the most recent New Zealand example being the 22 February 2011 Mw6.3 Christchurch earthquake. This earthquake caused significant damage to a majority of URM buildings in the Canterbury area and resulted in 185 fatalities. Many URM buildings still exist in various parts of New Zealand today, and due to their likely poor seismic performance, earthquake assessment and retrofit of the remaining URM building stock is necessary as these buildings have significant architectural heritage and occupy a significant proportion of the nation’s building stock. A collaborative research programme between the University of Auckland and Reid Construction Systems was conducted to investigate an economical yet effective solution for retrofitting New Zealand’s existing URM building stock. This solution adopts the shotcrete technique using an Engineered Cementitious Composite (ECC), which is a polyvinyl alcohol fibre reinforced mortar that exhibits strain hardening characteristics. Collaborations have been formed with a number of consulting structural engineers throughout New Zealand to develop innovative and cost effective retrofit solutions for a number of buildings. Two such case studies are presented in this paper. http://www.concrete2013.com.au/technical-program/
The 4 September, 22 February, and 13 June earthquakes experienced in Canterbury, New Zealand would have been significant events individually. Together they present a complex and unprecedented challenge for Canterbury and New Zealand. The repetitive and protracted nature of these events has caused widespread building and infrastructure damage, strained organisations’ financial and human resources and challenged insurer and investor confidence. The impact of the earthquakes was even more damaging coming in the wake of the worst worldwide recession since the great depression of the 1930s. However, where there is disruption there is also opportunity. Businesses and other organisations will drive the physical, economic and social recovery of Canterbury, which will be a dynamic and long-term undertaking. Ongoing monitoring of the impacts, challenges and developments during the recovery is critical to maintaining momentum and making effective mid-course adjustments. This report provides a synthesis of research carried out by the Resilient Organisations (ResOrgs) Research Programme1 at the University of Canterbury and Recover Canterbury in collaboration with Opus Central Laboratories (part of Opus International Consultants). The report includes discussions on the general state of the economy as well as data from three surveys (two conducted by ResOrgs and one by Recover Canterbury) on business impacts of the earthquakes, population movements and related economic recovery issues. This research and report offers two primary benefits:
In this paper we outline the process and outcomes of a multi-agency, multi-sector research collaboration, led by the Canterbury Earthquake Research Authority (CERA). The CERA Wellbeing Survey (CWS) is a serial, cross-sectional survey that is to be repeated six-monthly (in April and September) until the end of the CERA Act, in April 2016. The survey gathers self-reported wellbeing data to supplement the monitoring of the social recovery undertaken through CERA's Canterbury Wellbeing Index. Thereby informing a range of relevant agency decision-making, the CWS was also intended to provide the community and other sectors with a broad indication of how the population is tracking in the recovery. The primary objective was to ensure that decision-making was appropriately informed, with the concurrent aim of compiling a robust dataset that is of value to future researchers, and to the wider, global hazard and disaster research endeavor. The paper begins with an outline of both the Canterbury earthquake sequence, and the research context informing this collaborative project, before reporting on the methodology and significant results to date. It concludes with a discussion of both the survey results, and the collaborative process through which it was developed.
Seismic behaviour of typical unreinforced masonry (URM) brick houses, that were common in early last century in New Zealand and still common in many developing countries, is experimentally investigated at University of Canterbury, New Zealand in this research. A one halfscale model URM house is constructed and tested under earthquake ground motions on a shaking table. The model structure with aspect ratio of 1.5:1 in plan was initially tested in the longitudinal direction for several earthquakes with peak ground acceleration (PGA) up to 0.5g. Toppling of end gables (above the eaves line) and minor to moderate cracking around window and door piers was observed in this phase. The structure was then rotated 90º and tested in the transverse (short) direction for ground motions with PGA up to 0.8g. Partial out-of-plane failure of the face loaded walls in the second storey and global rocking of the model was observed in this phase. A finite element analysis and a mechanism analysis are conducted to assess the dynamic properties and lateral strength of the model house. Seismic fragility function of URM houses is developed based on the experimental results. Damping at different phases of the response is estimated using an amplitude dependent equivalent viscous damping model. Financial risk of similar URM houses is then estimated in term of expected annual loss (EAL) following a probabilistic financial risk assessment framework. Risks posed by different levels of damage and by earthquakes of different frequencies are then examined.
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.
Asset management in power systems is exercised to improve network reliability to provide confidence and security for customers and asset owners. While there are well-established reliability metrics that are used to measure and manage business-as-usual disruptions, an increasing appreciation of the consequences of low-probability high-impact events means that resilience is increasingly being factored into asset management in order to provide robustness and redundancy to components and wider networks. This is particularly important for electricity systems, given that a range of other infrastructure lifelines depend upon their operation. The 2010-2011 Canterbury Earthquake Sequence provides valuable insights into electricity system criticality and resilience in the face of severe earthquake impacts. While above-ground assets are relatively easy to monitor and repair, underground assets such as cables emplaced across wide areas in the distribution network are difficult to monitor, identify faults on, and repair. This study has characterised in detail the impacts to buried electricity cables in Christchurch resulting from seismically-induced ground deformation caused primarily by liquefaction and lateral spread. Primary modes of failure include cable bending, stretching, insulation damage, joint braking and, being pulled off other equipment such as substation connections. Performance and repair data have been compiled into a detailed geospatial database, which in combination with spatial models of peak ground acceleration, peak ground velocity and ground deformation, will be used to establish rigorous relationships between seismicity and performance. These metrics will be used to inform asset owners of network performance in future earthquakes, further assess component criticality, and provide resilience metrics.
Post-earthquake cordons have been used after seismic events around the world. However, there is limited understanding of cordons and how contextual information of place such as geography, socio-cultural characteristics, economy, institutional and governance structure etc. affect decisions, operational procedures as well as spatial and temporal attributes of cordon establishment. This research aims to fill that gap through a qualitative comparative case study of two cities: Christchurch, New Zealand (Mw 6.2 earthquake, February 2011) and L’Aquila, Italy (Mw 6.3 earthquake, 2009). Both cities suffered comprehensive damage to its city centre and had cordons established for extended period. Data collection was done through purposive and snowball sampling methods whereby 23 key informants were interviewed in total. The interviewee varied in their roles and responsibilities i.e. council members, emergency managers, politicians, business/insurance representatives etc. We found that cordons were established to ensure safety of people and to maintain security of place in both the sites. In both cities, the extended cordon was met with resistance and protests. The extent and duration of establishment of cordon was affected by recovery approach taken in the two cities i.e. in Christchurch demolition was widely done to support recovery allowing for faster removal of cordons where as in L’Aquila, due to its historical importance, the approach to recovery was based on saving all the buildings which extended the duration of cordon. Thus, cordons are affected by site specific needs. It should be removed as soon as practicable which could be made easier with preplanning of cordons.
As part of a seismic retrofit scheme, surface bonded glass fiber-reinforced polymer (GFRP) fabric was applied to two unreinforced masonry (URM) buildings located in Christchurch, New Zealand. The unreinforced stone masonry of Christchurch Girls’ High School (GHS) and the unreinforced clay brick masonry Shirley Community Centre were retrofitted using surface bonded GFRP in 2007 and 2009, respectively. Much of the knowledge on the seismic performance of GFRP retrofitted URM was previously assimilated from laboratory-based experimental studies with controlled environments and loading schemes. The 2010/2011 Canterbury earthquake sequence provided a rare opportunity to evaluate the GFRP retrofit applied to two vintage URM buildings and to document its performance when subjected to actual design-level earthquake-induced shaking. Both GFRP retrofits were found to be successful in preserving architectural features within the buildings as well as maintaining the structural integrity of the URM walls. Successful seismic performance was based on comparisons made between the GFRP retrofitted GHS building and the adjacent nonretrofitted Boys’ High School building, as well as on a comparison between the GFRP retrofitted and nonretrofitted walls of the Shirley Community Centre building. Based on detailed postearthquake observations and investigations, the GFRP retrofitted URM walls in the subject buildings exhibited negligible to minor levels of damage without delamination, whereas significant damage was observed in comparable nonretrofitted URM walls. AM - Accepted Manuscript
The author followed five primary (elementary) schools over three years as they responded to and began to recover from the 2010–2011 earthquakes in and around the city of Christchurch in the Canterbury region of New Zealand. The purpose was to capture the stories for the schools themselves, their communities, and for New Zealand’s historical records. From the wider study, data from the qualitative interviews highlighted themes such as children’s responses or the changing roles of principals and teachers. The theme discussed in this article, however, is the role that schools played in the provision of facilities and services to meet (a) physical needs (food, water, shelter, and safety); and (b) emotional, social, and psychological needs (communication, emotional support, psychological counseling, and social cohesion)—both for themselves and their wider communities. The role schools played is examined across the immediate, short-, medium-, and long-term response periods before being discussed through a social bonding theoretical lens. The article concludes by recommending stronger engagement with schools when considering disaster policy, planning, and preparation http://www.schoolcommunitynetwork.org/SCJ.aspx
The paper proposes a simple method for quick post-earthquake assessment of damage and condition of a stock of bridges in a transportation network using seismic data recorded by a strong motion array. The first part of the paper is concerned with using existing free field strong motion recorders to predict peak ground acceleration (PGA) at an arbitrary bridge site. Two methods are developed using artificial neural networks (a single network and a committee of neural networks) considering influential parameters, such as seismic magnitude, hypocentral depth and epicentral distance. The efficiency of the proposed method is explored using actual strong motion records from the devastating 2010 Darfield and 2011 Christchurch earthquakes in New Zealand. In the second part, two simple ideas are outlined how to infer the likely damage to a bridge using either the predicted PGA and seismic design spectrum, or a broader set of seismic metrics, structural parameters and damage indices.
