Fatality rates implied by the Italian building code

Iervolino, Iunio; Pacifico, Adriana

doi:10.1002/eqe.3472

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…This implies that this point corresponds to a minimum level of seismic safety that the structure will exhibit when designed under any q factor to the right of the demarcation line, since lateral resistance past that point should become insensitive to the reduction of seismic design actions. Thus, although it appears that uniform seismic safety cannot always be achieved between all sites by adjusting the behavior factor, one could acquiesce to q factors that allow structures to exhibit the same risk across high‐hazard sites while remaining below a certain risk threshold at low‐hazard sites, which can be possibly defined as acceptable according to some criterion 44 . However, as already discussed, what constitutes a high‐hazard or a low‐hazard site, in this context, is by no means obvious from the elastic design spectrum alone.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, although it appears that uniform seismic safety cannot always be achieved between all sites by adjusting the behavior factor, one could acquiesce to q factors that allow structures to exhibit the same risk across high-hazard sites while remaining below a certain risk threshold at low-hazard sites, which can be possibly defined as acceptable according to some criterion. 44 However, as already discussed, what constitutes a high-hazard or a low-hazard site, in this context, is by no means obvious from the elastic design spectrum alone.…”

Section: [-] [G] [-] [-] [G] [-] [-] [G] [-] [-] [G] [-]mentioning

confidence: 94%

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Seismic reliability implied by behavior‐factor‐based design

Baltzopoulos

Grella

Iervolino

2021

Earthq Engng Struct Dyn

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Force‐based seismic design involves the reduction of elastic spectra by introducing a behavior factor, q. This approach is widespread in engineering practice; however, recent studies have shown that structures consistently designed at different sites will not share the same level of seismic risk, which can be defined as the annual rate of the structure failing to meet a seismic performance objective, despite seismic actions having the same exceedance return period at all sites. This paper investigates whether the definition of site‐specific q factors can lead to uniform risk across sites characterized by varying levels of seismic hazard, based on the pushover curves of bare frame reinforced concrete buildings. These pushover curves are used to establish the backbones of equivalent single degree of freedom systems with varying lateral resistance. These systems are fictitiously placed at several Italian sites and their seismic failure risk is computed by integrating their fragility, assessed by means of incremental dynamic analysis, with each site's hazard curve. By assuming an arbitrary risk threshold, the same for all sites, the corresponding lateral strength leading to said threshold is determined and the corresponding behavior factor is back calculated. As expected, risk‐targeted q factors tend to increase with decreasing seismic hazard and are highly sensitive to the shape of the hazard curve beyond the design return period. Coupled with the fact that at low hazard sites lateral strength is determined by detailing for gravity‐load design and minimum code requirements, rather than seismic design actions, the results suggest that q factor‐based design is unsuitable for warranting territorially uniform seismic safety, yet it may be suitable for setting an upper‐bound to the annual failure probability.

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Section: Resultsmentioning

confidence: 99%

Section: [-] [G] [-] [-] [G] [-] [-] [G] [-] [-] [G] [-]mentioning

confidence: 94%

Seismic reliability implied by behavior‐factor‐based design

Baltzopoulos

Grella

Iervolino

2021

Earthq Engng Struct Dyn

Self Cite

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“…showed that designing structures based on uniform hazard does not result in structures with uniform risk, and introduced risk‐targeted seismic design maps. The nonuniform risk for structures designed by seismic code was recently confirmed for Italy 17 . A risk‐targeted approach was followed by Douglas et al 18 .…”

Section: Introductionmentioning

confidence: 99%

“…The nonuniform risk for structures designed by seismic code was recently confirmed for Italy. 17 A risk-targeted approach was followed by Douglas et al 18 and Silva et al, 19 who developed risk-targeted design maps for mainland France and Europe, respectively, but Japan remained conservative regarding risk-based seismic hazards due to reasons recently discussed by Suzuki et al 20 In parallel, many variants of seismic design procedures based on risk metrics were introduced. Franchin and Pinto 21 presented a method for seismic design of reinforced concrete structures to meet performance requirements expressed in terms of risk.…”

Section: Introductionmentioning

confidence: 99%

Risk‐targeted fragility functions considering a system performance requirement and domino effects

Celano,

Dolšek

2023

Earthq Engng Struct Dyn

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The design of structures depends on the performance requirements that are usually defined through structural codes for single units. This approach may not be optimal because major earthquakes affect the built environment and can also trigger domino effects due to fires, explosions or toxic dispersion. To overcome this issue, we introduce a probabilistic framework for defining unit performance requirements by means of risk‐targeted fragility functions that account for potential domino effects and an overall system performance requirement. The system performance requirement is demonstrated by the potential loss of life, which represents the tolerated number of fatalities per year expected in the earthquake‐affected area. The proposed framework decomposes the problem into a damage‐based fatality analysis, population analysis and seismic hazard analysis, which can be performed and improved independently by engineers with the relevant expertise. The damage‐based fatality analysis includes a series of Monte Carlo simulations using logic trees to account for domino effects. These analyses are then coupled with an iterative risk estimation aimed at identifying the critical units in a system and estimating their risk‐targeted fragility functions, which can then be used for the design of a single unit. The methodology is demonstrated by estimating the potential loss of life due to a seismic event in an urban industrial area. It is shown that the risk‐targeted fragility functions of hazardous storage tanks can be estimated in a few iterations based on disaggregating the potential loss of life. The pilot research presented in the paper provides new possibilities for defining seismic design parameters of structures.

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Methods for evaluating the significance and importance of differences amongst probabilistic seismic hazard results for engineering and risk analyses: a review and insights

Douglas,

Crowley,

Silva

et al. 2024

Bull Earthquake Eng

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When new seismic hazard estimates are published it is natural to compare them to existing results for the same location. This type of comparison routinely indicates differences amongst hazard estimates obtained with the various models. The question that then arises is whether these differences are scientifically significant, given the large epistemic uncertainties inherent in all seismic hazard estimates, or practically important, given the use of hazard models as inputs to risk and engineering calculations. A difference that exceeds a given threshold could mean that building codes may need updating, risk models for insurance purposes may need to be revised, or emergency management procedures revisited. In the current literature there is little guidance on what constitutes a significant or important difference, which can lead to lengthy discussions amongst hazard modellers, end users and stakeholders. This study reviews proposals in the literature on this topic and examines how applicable these proposals are, using, for illustration purposes, several sites and various seismic hazard models for each site, including the two European Seismic Hazard Models of 2013 and 2020. The implications of differences in hazard for risk and engineering purposes are also examined to understand how important such differences are for potential end users of seismic hazard models. Based on this, we discuss the relevance of such methods to determine the scientific significance and practical importance of differences between seismic hazard estimates and identify some open questions. We conclude that there is no universal criterion for assessing differences between seismic hazard results and that the recommended approach depends on the context. Finally, we highlight where additional work is required on this topic and that we encourage further discussion of this topic.

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Fatality rates implied by the Italian building code

Cited by 10 publications

References 11 publications

Seismic reliability implied by behavior‐factor‐based design

Seismic reliability implied by behavior‐factor‐based design

Risk‐targeted fragility functions considering a system performance requirement and domino effects

Methods for evaluating the significance and importance of differences amongst probabilistic seismic hazard results for engineering and risk analyses: a review and insights

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