Reliability of AASHTO LRFD parameters in multilane reinforced concrete slab bridges

Ali Ahmed Mahmood Mahmood; S. Najjar; M. Mabsout; K. Tarhini

doi:10.3233/BRS-190156

Reliability of AASHTO LRFD parameters in multilane reinforced concrete slab bridges

Ali Ahmed Mahmood Mahmood, S. Najjar, M. Mabsout, K. Tarhini

Research output: Contribution to journal › Article › peer-review

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.

Original language	English
Pages (from-to)	65-74
Number of pages	10
Journal	Bridge Structures
Volume	15
Issue number	1-2
DOIs	https://doi.org/10.3233/BRS-190156
Publication status	Published - 14 Aug 2019

Keywords

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

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10.3233/BRS-190156

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title = "Reliability of AASHTO LRFD parameters in multilane reinforced concrete slab bridges",

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",

author = "Mahmood, {Ali Ahmed Mahmood} and S. Najjar and M. Mabsout and K. Tarhini",

year = "2019",

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doi = "10.3233/BRS-190156",

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journal = "Bridge Structures",

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TY - JOUR

T1 - Reliability of AASHTO LRFD parameters in multilane reinforced concrete slab bridges

AU - Mahmood, Ali Ahmed Mahmood

AU - Najjar, S.

AU - Mabsout, M.

AU - Tarhini, K.

PY - 2019/8/14

Y1 - 2019/8/14

N2 - 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.

AB - 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.

KW - Concrete slab bridges

KW - finite-element analysis

KW - load-carrying capacity

KW - reliability analysis

U2 - 10.3233/BRS-190156

DO - 10.3233/BRS-190156

M3 - Article

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SP - 65

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JO - Bridge Structures

JF - Bridge Structures

IS - 1-2

ER -

Reliability of AASHTO LRFD parameters in multilane reinforced concrete slab bridges

Abstract

Keywords

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