Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead Load

According to modern structural codes, a design is considered to be adequate if the limit states are not exceeded. For the ultimate limit state, the design value of action effect E<sub>d</sub> is required to be less or equal than the design value of ultimate resistance R<sub>d</s...

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Main Authors: Goran Milutinovic, Rade Hajdin
Format: Article
Language:English
Published: MDPI AG 2024-01-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/14/3/985
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author Goran Milutinovic
Rade Hajdin
author_facet Goran Milutinovic
Rade Hajdin
author_sort Goran Milutinovic
collection DOAJ
description According to modern structural codes, a design is considered to be adequate if the limit states are not exceeded. For the ultimate limit state, the design value of action effect E<sub>d</sub> is required to be less or equal than the design value of ultimate resistance R<sub>d</sub>. This ensures, according to the Eurocode, a sufficiently low probability of failure expressed as the target reliability index β. Consequently, the distributions of action effect and of resistance need to satisfy the following conditions: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mfenced separators="|"><mrow><mi>E</mi><mo>></mo><msub><mrow><mi>E</mi></mrow><mrow><mi>d</mi></mrow></msub></mrow></mfenced><mo>≤</mo><mi mathvariant="sans-serif">Φ</mi><mfenced separators="|"><mrow><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>E</mi></mrow></msub><mi>β</mi></mrow></mfenced></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mfenced separators="|"><mrow><mi>R</mi><mo>≤</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msub></mrow></mfenced><mo>≤</mo><mi mathvariant="sans-serif">Φ</mi><mfenced separators="|"><mrow><mo>−</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>R</mi></mrow></msub><mi>β</mi></mrow></mfenced><mo>,</mo></mrow></semantics></math></inline-formula> where α<sub>E</sub> and α<sub>R</sub>, with |α| ≤ 1, are the values of the FORM sensitivity factors. The values of the sensitivity factors α<sub>E</sub> and α<sub>R</sub> are suggested, according to EN1990, as −0.7 and 0.8, respectively; for the accompanying actions, the sensitivity factor is recommended as 0.28. In this paper, the dependence of the sensitivity factors for traffic live load, dead load, and resistance on the ratio of traffic load to dead load is studied (which is directly proportional to the maximum span of the bridge). Significantly different sensitivity factors for resistance, dead load, and traffic load, other than proposed by the Eurocode, has been calculated for typical ratio of traffic to dead load. It further showed that, if it is assumed that E<sub>d</sub> = R<sub>d</sub> and the Eurocode partial safety factors are used, a different design point than the starting point, i.e., E<sub>d</sub> = R<sub>d</sub>, is obtained.
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spelling doaj.art-47163ddd457b4ed18b52a308839f7a9e2024-02-09T15:07:14ZengMDPI AGApplied Sciences2076-34172024-01-0114398510.3390/app14030985Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead LoadGoran Milutinovic0Rade Hajdin1Faculty of Civil Engineering, University of Belgrade, 11120 Belgrade, SerbiaFaculty of Civil Engineering, University of Belgrade, 11120 Belgrade, SerbiaAccording to modern structural codes, a design is considered to be adequate if the limit states are not exceeded. For the ultimate limit state, the design value of action effect E<sub>d</sub> is required to be less or equal than the design value of ultimate resistance R<sub>d</sub>. This ensures, according to the Eurocode, a sufficiently low probability of failure expressed as the target reliability index β. Consequently, the distributions of action effect and of resistance need to satisfy the following conditions: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mfenced separators="|"><mrow><mi>E</mi><mo>></mo><msub><mrow><mi>E</mi></mrow><mrow><mi>d</mi></mrow></msub></mrow></mfenced><mo>≤</mo><mi mathvariant="sans-serif">Φ</mi><mfenced separators="|"><mrow><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>E</mi></mrow></msub><mi>β</mi></mrow></mfenced></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mfenced separators="|"><mrow><mi>R</mi><mo>≤</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msub></mrow></mfenced><mo>≤</mo><mi mathvariant="sans-serif">Φ</mi><mfenced separators="|"><mrow><mo>−</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>R</mi></mrow></msub><mi>β</mi></mrow></mfenced><mo>,</mo></mrow></semantics></math></inline-formula> where α<sub>E</sub> and α<sub>R</sub>, with |α| ≤ 1, are the values of the FORM sensitivity factors. The values of the sensitivity factors α<sub>E</sub> and α<sub>R</sub> are suggested, according to EN1990, as −0.7 and 0.8, respectively; for the accompanying actions, the sensitivity factor is recommended as 0.28. In this paper, the dependence of the sensitivity factors for traffic live load, dead load, and resistance on the ratio of traffic load to dead load is studied (which is directly proportional to the maximum span of the bridge). Significantly different sensitivity factors for resistance, dead load, and traffic load, other than proposed by the Eurocode, has been calculated for typical ratio of traffic to dead load. It further showed that, if it is assumed that E<sub>d</sub> = R<sub>d</sub> and the Eurocode partial safety factors are used, a different design point than the starting point, i.e., E<sub>d</sub> = R<sub>d</sub>, is obtained.https://www.mdpi.com/2076-3417/14/3/985sensitivity factorpartial factor calibrationtraffic loadexisting bridges assessment
spellingShingle Goran Milutinovic
Rade Hajdin
Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead Load
Applied Sciences
sensitivity factor
partial factor calibration
traffic load
existing bridges assessment
title Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead Load
title_full Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead Load
title_fullStr Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead Load
title_full_unstemmed Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead Load
title_short Dependence of Sensitivity Factors on Ratio of Traffic Load to Dead Load
title_sort dependence of sensitivity factors on ratio of traffic load to dead load
topic sensitivity factor
partial factor calibration
traffic load
existing bridges assessment
url https://www.mdpi.com/2076-3417/14/3/985
work_keys_str_mv AT goranmilutinovic dependenceofsensitivityfactorsonratiooftrafficloadtodeadload
AT radehajdin dependenceofsensitivityfactorsonratiooftrafficloadtodeadload