Estimation of fragility functions using dynamic structural analysis is an important step in a number of seismic assessment procedures. This paper discusses the applicability of statistical inferenc...

Efficient analytical fragility function fitting using dynamic structural analysis

This paper presents recommended methodologies for the quantitative analysis of landslide hazard, vulnerability and risk at different spatial scales (site-specific, local, regional and national), as well as for the verification and validation of the results. The methodologies described focus on the evaluation of the probabilities of occurrence of different landslide types with certain characteristics. Methods used to determine the spatial distribution of landslide intensity, the characterisation of the elements at risk, the assessment of the potential degree of damage and the quantification of the vulnerability of the elements at risk, and those used to perform the quantitative risk analysis are also described. The paper is intended for use by scientists and practising engineers, geologists and other landslide experts.

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Recommendations for the quantitative analysis of landslide risk

Research and practice on progressive collapse and robustness of building structures in the 21st century

The National Institute of Standards and Technology (NIST) funded a project to improve guidance to the earthquake engineering profession for selecting and scaling earthquake ground motions for the purpose of performing nonlinear response-history analysis. The project supported problem-focused studies related to defining target spectra for seismic design and performance assessment, response-spectrum matching, and near-fault ground motions. Recommendations are presented for target spectra, selection of seed ground motions, and scaling of motions to be consistent with different target spectra. Minimum numbers of sets of motions are recommended for computing mean component and systems responses, and distributions of responses. Guidance is provided on selection and scaling of ground motions per ASCE/SEI 7-10.

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Selecting and Scaling Earthquake Ground Motions for Performing Response-History Analyses | NIST

A large amount of buildings was damaged or destroyed by the 2011 Great East Japan tsunami. Numerous field surveys were conducted in order to collect the tsunami inundation extents and building damage data in the affected areas. Therefore, this event provides us with one of the most complete data set among tsunami events in history. In this study, fragility functions are derived using data provided by the Ministry of Land, Infrastructure and Transportation of Japan, with more than 250,000 structures surveyed. The set of data has details on damage level, structural material, number of stories per building and location (town). This information is crucial to the understanding of the causes of building damage, as differences in structural characteristics and building location can be taken into account in the damage probability analysis. Using least squares regression, different sets of fragility curves are derived to demonstrate the influence of structural material, number of stories and coastal topography on building damage levels. The results show a better resistant performance of reinforced concrete and steel buildings over wood or masonry buildings. Also, buildings taller than two stories were confirmed to be much stronger than the buildings of one or two stories. The damage characteristic due to the coastal topography based on limited number of data in town locations is also shortly discussed here. At the same tsunami inundation depth, buildings along the Sanriku ria coast were much greater damaged than buildings from the plain coast in Sendai. The difference in damage states can be explained by the faster flow velocities in the ria coast at the same inundation depth. These findings are key to support better future building damage assessments, land use management and disaster planning.

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Building damage characteristics based on surveyed data and fragility curves of the 2011 Great East Japan tsunami

The Applied Technology Council is adapting PEER's performance-based earthquake engineering methodology to professional practice. The methodology's damage-analysis stage uses fragility functions to calculate the probability of damage to facility components given the force, deformation, or other engineering demand parameter (EDP) to which each is subjected. This paper introduces a set of procedures for creating fragility functions from various kinds of data: (A) actual EDP at which each specimen failed; (B) bounding EDP, in which some specimens failed and one knows the EDP to which each specimen was subjected; (C) capable EDP, where specimen EDPs are known but no specimens failed; (D) derived, where fragility functions are produced analytically; (E) expert opinion; and (U) updating, in which one improves an existing fragility function using new observations. Methods C, E, and U are all introduced here for the first time. A companion document offers additional procedures and more examples.

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Creating Fragility Functions for Performance-Based Earthquake Engineering:

A second-generation performance-based earthquake engineering (PBEE-2) procedure has been developed by the Pacific Earthquake Engineering Research (PEER) Center and others that estimates the probabilistic future seismic performance of buildings and bridges in terms of system-level decision variables such as repair cost, casualties, and loss of use (dollars, deaths and downtime). The Applied Technology Council has undertaken to transfer the methodology to professional practice [ATC 2005]. The methodology involves four stages: hazard analysis, structural analysis, damage analysis, and loss analysis. This paper addresses the damage analysis, whose inputs are demand parameters calculated in a suite of multiple-degree-of-freedom nonlinear dynamic analyses, and whose output is the damage state of each damageable structural and nonstructural component in the facility. The analysis uses fragility functions, which in this context give the probability that a component, element or system will be damaged to a given or more severe damage state as a function of a single predictive demand parameter such as story drift or floor acceleration. One such fragility function is required for each component type and damage state. Many building-component fragility functions have been created in the past, but no comprehensive set of procedures exists on how to create them. This paper summarizes such a standard developed for ATC-58. See Porter et al. [2006] for more detail, examples, commentary, and alternative approaches.

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Robert Kennedy

Papers

Creating Fragility Functions for Performance-Based Earthquake Engineering:

Practical Development and Application of Fragility Functions