Resistance Model for Reliability Analysis of Existing Steel Girder Bridges

강거더 교량의 신뢰성해석을 위한 저항모델 개발

  • 엄준식 (상지대학교 건설시스템공학과)
  • Received : 2013.10.30
  • Accepted : 2013.12.13
  • Published : 2013.12.25

Abstract

Because of financial and safety concerns, there are needs for more accurate prediction of bridge behavior. Underestimation of the bridge load carrying capacity can have serious economic consequences, as deficient bridges must be repaired or rehabilitated. Therefore, the knowledge of the actual bridge behavior under live load may lead to a more realistic calculation of the load carrying capacity and eventually this may allow for more bridges to remain in service with or without minor repairs. The presented research is focused on the reliability evaluation of the actual load carrying capacity of existing bridges based on the field testing. Seventeen existing bridges were tested under truck load to confirm their adequacy of reliability. The actual response of existing bridge structures under live load is measured. Reliability analysis is performed on the selected representative bridges designed in accordance with AASHTO codes for bridge component (girder). Bridges are first evaluated based on the code specified values and design resistance. However, after the field testing program, it is possible to apply the experimental results into the bridge reliability evaluation procedures. Therefore, the actual response of bridge structures, including unintentional composite action, partial fixity of supports, and contribution of nonstructural members are considered in the bridge reliability evaluation. The girder distribution factors obtained from the tests are also applied in the reliability calculation. The results indicate that the reliability indices of selected bridges can be significantly increased by reducing uncertainties without sacrificing the safety of structures, by including the result of field measurement data into calculation.

Keywords

References

  1. AASHTO LRFD Bridge Design Specifications, American Association of State Highway and Transportation Officials, Washington, D.C., 2013.
  2. AASHTO Standard Specifications for Highway Bridges. American Association of State Highway and Transportation Officials, Washington, D.C., 2002.
  3. FHWA bridge programs material type of structure by state, Federal Highway Administration, 2009.
  4. Y.I. Kwon, S.J. Kim and H.W. Lee (2009), "Service Life Prediction of CFRP bar for Concrete Reinforcement based on Accelerated degradation tests," J. Applied Reliability, Vol.9, No.2, pp71-80.
  5. J. Laman (1995), "Fatigue Load Models for Girder Bridges," Ph.D. dissertation, Department of Civil Engineering, University of Michigan, Ann Arbor, Michigan.
  6. A.G. Lichtenstein (1993), "Bridge Rating Through Nondestructive Load Testing," NCHRP report No. 12-28(13)A, National Cooperative Highway Research Program.
  7. R. Rackwitz, and B. Fiessler (1978), "Structural Reliability under Combined Random Load Sequences," Computer and Structures, Vol. 9, pp. 489-494.. https://doi.org/10.1016/0045-7949(78)90046-9
  8. J.L. Schultz, B. Commander, G.G. Goble, and D.M. Frangpol (1995), "Efficient Field Testing and Load Rating of Short and Medium Span Bridges," Structural Engineering Review, Vol. 7, No 3, pp. 181-194.