Earthquake Engineering and Engineering Vibration

, Volume 11, Issue 3, pp 303–311 | Cite as

Towards multiple hazard resilient bridges: a methodology for modeling frequent and infrequent time-varying loads Part II, Examples for live and earthquake load effects

Article

Abstract

The current AASHTO load and resistance factor design (LRFD) guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major advancement in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. Combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variable and cannot be directly combined with time invariant loads to formulate the probability of structural failure. To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a certain condition can be approximated as time invariant. Based on these conditions, the extreme loads (also referred to as multiple hazard or MH loads) can be broken down into single effects. In this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example.

Keywords

multiple hazards bridge probability-based design comprehensive reliability partial failure probability 

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References

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  3. Liang Z and Lee GC (2012), “Towards Multiple Hazard Resilient Bridges: a Methodology for Modeling Frequent and Infrequent Time-varying Loads, Part I, Comprehensive Reliability and Partial Failure Probabilities,” Earthquake Engineering and Engineering Vibration, 11(3): 293–301.Google Scholar
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Copyright information

© Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Department of Mechanical and Aerospace EngineeringUniversity at BuffaloBuffaloUSA
  2. 2.Department of Civil, Structural and Environmental EngineeringUniversity at BuffaloBuffaloUSA

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