A press release from the United States of America Embassy New Zealand containing a statement by FEMA Administrator Craig Fugate regarding the 22 February 2011 earthquake in Christchurch.
A blog post from US Ambassador to New Zealand and Samoa, David Huebner, titled, "Christchurch Earthquake Teams in Motion".
A press release from the United States of America Embassy New Zealand, about their response to the 22 February 2011 earthquake in Christchurch.
A blog post from US Ambassador to New Zealand and Samoa, David Huebner, titled, "Tim Manning Remembers February 22nd".
The 2010-2011 Canterbury earthquake sequence, and the resulting extensive data sets on damaged buildings that have been collected, provide a unique opportunity to exercise and evaluate previously published seismic performance assessment procedures. This poster provides an overview of the authors’ methodology to perform evaluations with two such assessment procedures, namely the P-58 guidelines and the REDi Rating System. P-58, produced by the Federal Emergency Management Agency (FEMA) in the United States, aims to facilitate risk assessment and decision-making by quantifying earthquake ground shaking, structural demands, component damage and resulting consequences in a logical framework. The REDi framework, developed by the engineering firm ARUP, aids stakeholders in implementing resilience-based earthquake design. Preliminary results from the evaluations are presented. These have the potential to provide insights on the ability of the assessment procedures to predict impacts using “real-world” data. However, further work remains to critically analyse these results and to broaden the scope of buildings studied and of impacts predicted.
Deputy Administrator for Protection and National Preparedness at the Federal Emergency Management Agency, Tim Manning, and Michael Layne from the US Embassy in Wellington, speaking to Ray Kennedy, an Area Manager from the New Zealand Fire Service, in the Christchurch Art Gallery about the 22 February 2011 earthquake.
Low Damage Seismic Design (LDSD) guidance material being developed by Engineering NZ is considering a design drift limit for multi-storey buildings of 0.5% at a new damage control limit state (DCLS). The impact of this new design requirement on the expected annual loss due to repair costs is investigated for a four-storey office building with reinforced concrete walls located in Christchurch. The LDSD guidance material aims to reduce the expected annual loss of complying buildings to below 0.1% of building replacement cost. The research tested this expectation. Losses were estimated in accordance with FEMA P58, using building responses from non-linear time history analyses (performed with OpenSees using lumped plasticity models). The equivalent static method, in line with NZS 1170.5 and NZS 3101, was used to design the building to LDSD specifications, representing a future state-of-practice design. The building designed to low-damage specification returned an expected annual loss of 0.10%, and the building designed conventionally returned an expected annual loss of 0.13%. Limitations with the NZS 3101 method for determining wall stiffness were identified, and a different method acknowledging the relationship between strength and stiffness was used to redesign the building. Along with improving this design assumption, the study finds that LDSD design criteria could be an effective way of limiting damage and losses.
The 22nd February 2011, Mw 6.3 Christchurch earthquake in New Zealand caused major damage to critical infrastructure, including the healthcare system. The Natural Hazard Platform of NZ funded a short-term project called “Hospital Functions and Services” to support the Canterbury District Health Board’s (CDHB) efforts in capturing standardized data that describe the effects of the earthquake on the Canterbury region’s main hospital system. The project utilised a survey tool originally developed by researchers at Johns Hopkins University (JHU) to assess the loss of function of hospitals in the Maule and Bío-Bío regions following the 27th February 2010, Mw 8.8 Maule earthquake in Chile. This paper describes the application of the JHU tool for surveying the impact of Christchurch earthquake on the CDHB Hospital System, including the system’s residual capacity to deliver emergency response and health care. A short summary of the impact of the Christchurch earthquake on other CDHB public and private hospitals is also provided. This study demonstrates that, as was observed in other earthquakes around the world, the effects of damage to non-structural building components, equipment, utility lifelines, and transportation were far more disruptive than the minor structural damage observed in buildings (FEMA 2007). Earthquake related complications with re-supply and other organizational aspects also impacted the emergency response and the healthcare facilities’ residual capacity to deliver services in the short and long terms.
By closely examining the performance of a 22-storey steel framed building in Christchurch subject to various earthquakes over the past seven years, it is shown that a number of lessons can be learnt regarding the cost-effective consideration of non-structural elements. The first point in this work is that non-structural elements significantly affected the costs associated with repairing steel eccentrically braced frame (EBF) links. The decommissioning or rerouting of non-structural elements in the vicinity of damaged links in the case study building attributed to approximately half the total cost of their repair. Such costs could be significantly reduced if the original positioning of non-structural elements took account of the potential need to repair the EBF links. The second point highlighted is the role that pre-cast cladding apparently played on the distribution and type of damage in the building. Loss estimates obtained following the FEMA P-58 framework vary considerably when cladding is or isnt modelled, both because of changes to drift demands up the height of the building and because certain types of subsequent damage are likely to be cheaper to repair than others. Finally, costly repairs to non-structural partition walls were required not only after the moment magnitude 7.1 earthquake in 2010 but also in multiple aftershocks in the years that followed. Repair costs associated with aftershock events exceeded those from the main event, emphasizing the need to consider aftershocks within modern performance-based earthquake engineering and also the opportunity that exists to make more cost-effective repair strategies following damaging earthquakes.
The recent Canterbury earthquake sequence in 2010-2011 highlighted a uniquely severe level of structural damage to modern buildings, while confirming the high vulnerability and life threatening of unreinforced masonry and inadequately detailed reinforced concrete buildings. Although the level of damage of most buildings met the expected life-safety and collapse prevention criteria, the structural damage to those building was beyond economic repair. The difficulty in the post-event assessment of a concrete or steel structure and the uneconomical repairing costs are the big drivers of the adoption of low damage design. Among several low-damage technologies, post-tensioned rocking systems were developed in the 1990s with applications to precast concrete members and later extended to structural steel members. More recently the technology was extended to timber buildings (Pres-Lam system). This doctoral dissertation focuses on the experimental investigation and analytical and numerical prediction of the lateral load response of dissipative post-tensioned rocking timber wall systems. The first experimental stages of this research consisted of component testing on both external replaceable devices and internal bars. The component testing was aimed to further investigate the response of these devices and to provide significant design parameters. Post-tensioned wall subassembly testing was then carried out. Firstly, quasi-static cyclic testing of two-thirds scale post-tensioned single wall specimens with several reinforcement layouts was carried out. Then, an alternative wall configuration to limit displacement incompatibilities in the diaphragm was developed and tested. The system consisted of a Column-Wall-Column configuration, where the boundary columns can provide the support to the diaphragm with minimal uplifting and also provide dissipation through the coupling to the post-tensioned wall panel with dissipation devices. Both single wall and column-wall-column specimens were subjected to drifts up to 2% showing excellent performance, limiting the damage to the dissipating devices. One of the objectives of the experimental program was to assess the influence of construction detailing, and the dissipater connection in particular proved to have a significant influence on the wall’s response. The experimental programs on dissipaters and wall subassemblies provided exhaustive data for the validation and refinement of current analytical and numerical models. The current moment-rotation iterative procedure was refined accounting for detailed response parameters identified in the initial experimental stage. The refined analytical model proved capable of fitting the experimental result with good accuracy. A further stage in this research was the validation and refinement of numerical modelling approaches, which consisted in rotational spring and multi-spring models. Both the modelling approaches were calibrated versus the experimental results on post-tensioned walls subassemblies. In particular, the multi-spring model was further refined and implemented in OpenSEES to account for the full range of behavioural aspects of the systems. The multi-spring model was used in the final part of the dissertation to validate and refine current lateral force design procedures. Firstly, seismic performance factors in accordance to a Force-Based Design procedure were developed in accordance to the FEMA P-695 procedure through extensive numerical analyses. This procedure aims to determine the seismic reduction factor and over-strength factor accounting for the collapse probability of the building. The outcomes of this numerical analysis were also extended to other significant design codes. Alternatively, Displacement-Based Design can be used for the determination of the lateral load demand on a post-tensioned multi-storey timber building. The current DBD procedure was used for the development of a further numerical analysis which aimed to validate the procedure and identify the necessary refinements. It was concluded that the analytical and numerical models developed throughout this dissertation provided comprehensive and accurate tools for the determination of the lateral load response of post-tensioned wall systems, also allowing the provision of design parameters in accordance to the current standards and lateral force design procedures.