Keynote Address Tribute to Tom Paulay Session 3 Session 4A Session 4B Session 5A Session 5B Session 6 Session 7A Session 7B Session 8A Session 8B Poster Session 

Organizational model of a hospital system

Gian Paolo Cimellaro, Andrei Reinhorn and Michel Bruneau

The capacity and the dynamic response of a hospital network has been estimated using an organizational metamodel that is able to incorporate the influence of facility damage of structural and no-structural components on the organizational system. The waiting time of a patient before receiving treatment is selected as an aggregated function describing the global functionality of technical and organizational aspects and it is used to evaluate the seismic resilience of the hospital network. The metamodel of a single hospital has been used to evaluate the resilience of a hospital network of two hospitals in presence of an Operative Center, including the damage of the hospital buildings and the roadway system.

Paper P20: [Read]

Seismic Assessment of Engineering Systems in Hospitals - A Challenge for Operational Continuity

S.R. Uma and Graeme Beattie

Hospitals are treated as critical facilities which are required to continue functioning after an earthquake event. The expected continued performance of hospitals is greatly dependent on the satisfactory performance of engineering systems surviving seismic demands through their adequate seismic restraints. To understand the potential problems and inadequacies with existing engineering systems within critical facilities, three hospitals in Wellington region were surveyed. The survey focused on ‘essential’ systems required to sustain the operational continuity of hospitals including floor mounted components with rigid and resilient mountings and suspended components. The study revealed that most of the components have been provided with some degree of restraint. However, there were systems with inadequate restraints which could potentially impair their individual functioning requirement or interact with adjacent components resulting in combined failure of the systems. The paper highlights the observations in terms of the vulnerability of the components, the existing scenario of their restraints and their impact on seismic safety. Finally, a brief note is made on the observed current practice within consultancy firms towards the seismic design and installation of engineering systems. In conclusion, the ‘operational continuity’ performance criteria can possibly be achieved through a rigorous framework adopting careful design and installation of components of engineering systems and mainly followed by thorough inspection of all the components considering their interaction effects.

Paper P21: [Read]

Site class determinations (NZS 1170.5) in Wellington using borehole data and microtremor techniques

N.D. Perrin, W.R. Stephenson and S. Semmens

Wellington has a high seismic hazard due to its close proximity of several major fault systems, with the Wellington Fault crossing the north-western central city, and deep sedimentary basins in which amplification of incident bedrock shaking can be expected during earthquakes.

Under the “It’s Our Fault” project, a 3D geological model of Wellington’s central business district has been constructed and used to define areas of different seismic subsoil class [Rus1] as defined in NZS 1170.5, and depth to rock, at a scale useful for site-specific analysis (e.g. 1:5,000). This model to based on a compilation of 1025 borelogs and surface geology.

Shear wave velocity (Vs) estimates have been made for the geological materials present in central Wellington, including greywacke bedrock, based on ~20 direct measurements of shear wave velocities by means of seismic CPT, vertical seismic profiling and seismic refraction. These Vs determinations have been correlated/substantiated with results from three microtremor techniques: SPAC (SPatial AutoCorrelation), ReMi (Refraction Microtremor), and HVSR (Horizontal to Vertical Spectral Ratio, commonly referred to as the “Nakamura Method”). Generally the near-surface deposits (typically loose to dense silt, sand and gravel)[Rus3] have Vs in the order of 150 m/sec, but the deeper sediments (silt/sand/gravel mixtures) range from about 300 to 700 m/sec. Weathered bedrock has velocities around 600 m/sec, but 1000 to 1100 m/sec is more typical for unweathered rock.

Paper P22: [Read]

It’s Our Fault: Re-evaluation of Wellington Fault conditional probability of rupture

D.A. Rhoades, R.J. Van Dissen, R.M. Langridge, T.A. Little, D. Ninis, E.G.C. Smith and R. Robinson

A primary goal of the Likelihood Phase of the “It’s Our Fault” (IOF) project was a re-evaluation of the conditional probability of rupture of the Wellington-Hutt Valley segment of the Wellington Fault accounting for new IOF-catalysed Wellington Fault data. There are now new estimates of: 1) the timing of the most recent rupture, and the previous four older ruptures; 2) the size of single-event displacements; 3) the Holocene dextral slip-rate; and 4) rupture statistics of the Wellington-Wairarapa fault-pair, as deduced from synthetic seismicity modelling. Using these new data, the probability of rupture was calculated as a single value that accounts for both data and parameter uncertainties. Four recurrence-time models (exponential, lognormal, Weibull and Brownian passage-time) were explored, and a sensitivity analysis was conducted entertaining different bounds and shapes of the probability distributions of important fault rupture data and parameters. The results show that the estimated probability of rupture in the next 100 years is ~11% (with sensitivity results ranging from 4% to 15%). The new IOF data have reduced the estimated probability of rupture by ~50%, or more, compared to pre-IOF estimates.

Paper P23: [Read]

Modelling Interdependences of Critical Infrastructure

Rob Buxton, S.R. Uma and Andrew King

The well-being of our society depends on the successful functioning of local, national and international infrastructure networks. Some of the life-line utility networks include water supply, telecommunication, and transportation networks. These networks are spatially distributed and their performance is greatly influenced by the individual performance of their components, but they are also dependent on other utility networks resulting in complex interactions between network systems. Consequently the failure of components in a single utility network could potentially affect functioning of not only its own network system but also the other networks which are dependent on it. This failure phenomenon is referred as “cascading failure”.

The urgent need for addressing the complex problem of interdependencies between different utility networks and the consequences of cascading failures has been recently recognised. Wellington, being vulnerable to large earthquakes, and having great complexity and interdependency in its network systems is at risk in this regard, which needs to be mitigated for the resilience of the community.

In this paper we briefly discuss some recent approaches to modelling interdependencies in infrastructure systems and outline the use of Bayesian Belief Networks as an alternative approach.

Paper P24: [Read]

Wellington Earthquake National Initial Response Plan

Tane Woodley

Project Objectives: To develop a national-level initial response plan for a major Wellington Earthquake, designed to direct and coordinate the immediate national response until a formal re-sponse structure and specific national action plan has been established. This will ensure that the initial response actions taken in the immediate aftermath following a major Wellington Earth-quake are widely understood, coordinated and make the best use of scarce resources.

Project Methodology: The project initially established the probable range of impacts from a ma-jor Wellington Earthquake, and then used this planning scenario to workshop a plan with stake-holder agencies. The draft plan was reviewed by stakeholders twice, before being tested in indi-vidual workshops.

Results to be Obtained: As of February 2010, the plan is still in development. Once completed it will document how the initial national response to a Wellington Earthquake will be conducted by government agencies, lifelines and NGOs. This includes stating response objectives and priori-ties, specifying tasks for response agencies and describing the logistics and information systems.

Significance of the Results: The final plan will provide the Director of Civil Defence Emer-gency Management a framework on which to base the national response to a major Wellington Earthquake. This framework has been developed and agreed with stakeholder agencies and indus-try, and will enable any response to be conducted in a more timely and effective manner.

Paper P25: [Read]

Keynote Address Tribute to Tom Paulay Session 3 Session 4A Session 4B Session 5A Session 5B Session 6 Session 7A Session 7B Session 8A Session 8B Poster Session