Target reliability for existing structures considering economic and societal aspects

Sýkora, Milan; Diamantidis, Dimitris; Holický, Milan; Jung, Karel

doi:10.1080/15732479.2016.1198394

Cited by 78 publications

(27 citation statements)

References 26 publications

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“…It is observed that for larger N, the fib bulletin 80 for existing structures requires higher reliability levels than the ISO standard for new structures ('small relative life-saving costs'). This is in contradiction with numerous previous studies advocating lower target levels for existing structures [8,19,[23][24][25] and with the theoretically justified approach to reduce target reliability levels for increasing costs of safety measures. The discrepancy is primarily attributable to the risk-averse value k = 2 adopted in the fib bulletin.…”

Section: Application To a Railway Bridgecontrasting

confidence: 50%

“…Essentially, this approach combines economic and human safety aspects. Compared with economic optimization [8,[21][22][23], it should lead to lower target reliability indices, as only the human consequences of structural failure are taken into account, while other losses such as economic and environmental costs are not taken into account. In the LQI approach, the danger to which the people are subjected might vary on an individual basis within the group of people affected, which may be deemed unethical [8].…”

Section: Iso 2394 Recommendationsmentioning

confidence: 99%

See 1 more Smart Citation

Human safety criteria for risk-based structural design

Sýkora¹,

Holický²,

Jung³

et al. 2018

Int. J. SAFE

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Risk and reliability criteria are well established in many industrial sectors such as the offshore, chemical or nuclear industries. Comparative risk thresholds have been specified to allow a responsible organization or regulator to identify activities, which impose an acceptable level of risk concerning the participating individuals, or society as a whole. The scope of this contribution is to present target reliability criteria based on acceptable human safety levels. Application of theoretical principles is illustrated by examples of railway engineering structures. Initially it is shown how civil engineering structures for which human safety criteria play a role are classified according to Eurocodes. Examples include bridges, tunnels or station buildings. The general concepts for risk acceptance are then briefly reviewed, particularly in their relation to the target reliability criteria. The distinction between the two types of criteria is made: group risk and the acceptance criterion based on the Life Quality Index LQI approach introduced by ISO 2394:2015. The differences between the criteria for new and existing structures are discussed. The application is illustrated by an example of a bridge crossing an important railway line. It appears that while benefits and costs of a private stakeholder or public authority are reflected by economic optimisation, the society should define the limits for human safety to achieve uniform risks for various daily-life activities and across different industrial sectors.

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Section: Application To a Railway Bridgecontrasting

confidence: 50%

Section: Iso 2394 Recommendationsmentioning

confidence: 99%

Human safety criteria for risk-based structural design

Sýkora¹,

Holický²,

Jung³

et al. 2018

Int. J. SAFE

Self Cite

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“…The methodology proposed by fib Bulletin N°80 to define the target reliability levels for existing bridges is summarized in Table . Note that similar values can be achieved adopting the Life Quality Index (LQI) approach . In the following, the methodologies proposed by fib Bulletin 80 devoted to the evaluation of the partial safety factors for existing structures are described.…”

Section: Basic Notions Related To Both the Partial Factor Methods And mentioning

confidence: 99%

“…Note that similar values can be achieved adopting the Life Quality Index (LQI) approach. 9,[18][19][20] In the following, the methodologies proposed by fib Bulletin 80 11 devoted to the evaluation of the partial safety factors for existing structures are described.…”

Section: The Partial Factor Methods According To En1990mentioning

confidence: 99%

Partial factor methods for existing structures according to fib Bulletin 80: Assessment of an existing prestressed concrete bridge

Gino

Castaldo

Bertagnoli

et al. 2019

Structural Concrete

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The assessment of existing reinforced concrete structures is one of the major aspects for engineers and practitioners. In particular, existing infrastructures, as bridges and viaducts, are extensively exposed to environmental actions, materials aging, degradation, and variation of magnitude of traffic loads during their service life. Hence, the assessment of existing structural systems assuming the same criteria conceived for the design (i.e., partial factor method—EN 1990) can be too conservative and, sometimes, may lead to unnecessary and expensive structural interventions. In this context, fib Bulletin 80 defines the partial factor methods suitable for the assessment of existing reinforced concrete structures accounting for their residual service life, information from in situ and laboratory tests, measurements of variable actions and reduced target reliability levels according to both economical and human safety criteria. The methodologies proposed in fib Bulletin 80 have been applied to assess the safety of an existing prestressed reinforced concrete bridge built in 90s and located in Italy. The results are compared to the outcomes from the assessment performed according to EN1990 and, finally, limits and advantages of the methodologies proposed by fib Bulletin 80 are discussed.

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“…The level of information when erecting new structures and rehabilitating existing ones is fundamentally different, as the latter already exists in tangible form, can be investigated, and its structural performance can be considered. Thus, different adjustments of target values for existing structures are discussed in the literature, see, e.g., [22] or [23]. Here, β = 3.2 is assumed for a reference period of T ref = 50a.…”

Section: Update Of the Partial Safety Factor Based On Testing (Kl 2c)mentioning

confidence: 99%

The Influence of Improved Strength Grading In Situ on Modelling Timber Strength Properties

2020

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The management and preservation of structures in our built environment are central and challenging tasks for practicing engineers. Within the CEN member states (European Committee for Standardization), the so-called Eurocodes form the basis of the design and verification of the load-bearing capacity of structures. Current Eurocodes do not contain special recommendations for existing structures, meaning that the principles for new structures are applied. This can lead to an incorrect estimation of the load-bearing capacity within the semi-probabilistic safety concept. A central task within the investigation and evaluation of existing structures is the strength grading of the material in situ using non-/semi-destructive technical devices. Studies show the potential of the ultrasonic time-of-flight measurement in combination with visual evaluation for an improved grading. The information on the material from an improved grading technique can be used to update the material parameters as a target variable using a measured reference variable. In this contribution, test data from a partner project (spruce, pine, and oak) are analyzed, applying the stochastic grading model of Pöhlmann and Rackwitz. It can be shown that different grading techniques influence the updated distribution function of the material strength within the grade. The results depend on the timber species. Perspectives to develop updated models dependent on the knowledge available are shown and discussed.

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Target reliability for existing structures considering economic and societal aspects

Cited by 78 publications

References 26 publications

Human safety criteria for risk-based structural design

Human safety criteria for risk-based structural design

Partial factor methods for existing structures according to fib Bulletin 80: Assessment of an existing prestressed concrete bridge

The Influence of Improved Strength Grading In Situ on Modelling Timber Strength Properties

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