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Ramifications of blind adoption of load and resistance factors in building codes: reliability-based assessment

Mahmoudkalayeh, S ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1007/s10518-020-01015-7
  3. Publisher: Springer Science and Business Media B.V , 2021
  4. Abstract:
  5. This paper presents a probabilistic approach to reveal the negative consequences of overlooking code calibration when adopting the provisions of nonindigenous building codes in design. A taxonomy of the national building codes of various countries whose provisions are adopted from one or more original standards is first presented. Next, the reliability-based approach to quantify the lack of safety that may arise due to the absence of code calibration is presented. This approach is then applied to the case study of the National Building Code of Iran, whose load and resistance factors are directly adopted from ASCE/SEI 7. To this end, seven steel building archetypes with various structural systems at various regions with different seismicity levels and site classes are designed according to the Iranian loading and steel design codes. Subsequently, 2510 structural elements, including beams, columns, and braces, from these archetypes are subjected to reliability analysis to compute their reliabilities. In this analysis, the uncertainty of material properties are quantified using local laboratory test data and the uncertainties associated with manufacturing tolerances of steel elements are quantified through extensive field surveys. The analysis results in reliability indices that are markedly smaller than the targets set by the original standards the Iranian code has adopted from, which exposes the notable lack of safety in the ensuing designs. Subsequently, the load and resistance factors are calibrated to achieve the target reliabilities. Among other changes, the results indicate the need for a 25% increase in the earthquake load factor, which reveals the lack of safety that is implicit in the current practice. Reliability sensitivity analysis is then employed to determine the sources of uncertainty that are most influential on the resulting reliabilities. The presented approach is immediately applicable to the assessment of the building codes of other countries. © 2021, The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature
  6. Keywords:
  7. Architectural design ; Building codes ; Calibration ; Fits and tolerances ; Safety factor ; Sensitivity analysis ; Uncertainty analysis ; Load and resistance factor ; Manufacturing tolerances ; National Building Code ; Probabilistic approaches ; Reliability sensitivity analysis ; Sources of uncertainty ; Structural elements ; Target reliability ; Reliability analysis ; Assessment method ; Building ; Design ; Manufacturing ; Probability ; Safety ; Steel ; Structural response ; Iran
  8. Source: Bulletin of Earthquake Engineering ; Volume 19, Issue 2 , 2021 , Pages 963-986 ; 1570761X (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s10518-020-01015-7