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Abstract

Empirical expressions for estimating live load bending moments are typically specified in AASHTO bridge codes. This paper will evaluate the reliability levels that are inherent in the simplified empirical equations in the AASHTO LRFD to design concrete slab bridges. Typical one-span, multilane, straight bridges, with various span lengths are modeled using finite element analysis (FEA) and subjected to AASHTO live loads. FEA results are compared with LRFD moments to quantify biases that might result from the simplifying assumptions in AASHTO. The reliability index β for bridge cases using AASHTO procedures and FEA results were quantified. The results of this analysis showed that current live load factors in AASHTO LRFD procedures were below the required levels of reliability index (β <3.5) for one-lane bridges, and those indices were higher for multilane bridges, yet did not reach the required level, thus proposing to increase the AASHTO live load factors.

Keywords

Concrete slab bridges finite-element analysis load-carrying capacity reliability analysis

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References

AASHTO. Standard Specifications for Highway Bridges (17th ed). American Association of State Highway and Transportation Officials (AASHTO), Washington, DC. 2002.

AASHTO LRFD Bridge Design Specifications (6th ed). American Association of State Highway and Transportation Officials (AASHTO), Washington, DC. 2012.

Kulicki

, Prucz

, Clancy

, Mertz

, Nowak

. Updating the Calibration Report for AASHTO LRFD Code. Final Report, Project No. NCHRP 20-7/186. Washington, DC: Transportation Research Board of the National Academies. 2007.

Mabsout

, Tarhini

, Frederick

, Tayar

. Finite element analysis of steel girder highway bridges. Journal of Bridge Engineering. 1997;2(3):83–87. American Society of Civil Engineers (ASCE).

Mabsout

, Tarhini

, Jabakhanji

, Awwad

. Wheel load distribution in simply supported concrete slab bridges. Journal of Bridge Engineering. 2004;9(2):147–155. American Society of Civil Engineers (ASCE).

Mahmood

, Najjar

, Mabsout

, Tarhini

. Reliability analysis of reinforced concrete slab bridges. International Journal of GEOMATE. 2017;13(36):44–49. GEOMATE International Society.

Nowak

. Calibration of LRFD bridge code. Journal of Structural Engineering. 1995;121(8):1245–51. American Society of Civil Engineers (ASCE).

Nowak

. Calibration of LRFD Bridge Design Code. NCHRP Report 368.Washington, DC. Transportation Research Board. 1999.

SAP2000 (version 19). Computers and Structures Inc. Berkeley, California.