Experimental and Analytical Investigation of Live-Load Distribution Factors for Double Tee Bridges

Torres, Victor J.; Zolghadri, Navid; Maguire, Marc; Barr, Paul; Halling, Marvin W.

doi:10.1061/(asce)cf.1943-5509.0001259

Cited by 7 publications

(4 citation statements)

References 21 publications

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“…Gheitasi and Harris [8] show an overestimation of the stresses obtained when using the LDF quantified as 125% for interior girders and greater than 300% for exterior girders. Likewise, Huang, Semendary and Razzaq [10][11][12][13][14][15][16][17][18][19][20][21][22] quantify the overestimation of the longitudinal bending stresses experienced by the girders obtained using the LDF method as 150%.…”

Section: Discussionmentioning

confidence: 99%

“…The LDF concept was first introduced by the American Association of State Highway Officials (AASHO) in 1931 [19].These methods roughly calculate the cross-sectional distribution on girder bridge decks using empirical formulas. The LDF is calculated from a series of formulations that parametrically treat the calculation of the percentage of bending moment and shear stress supported by the longitudinal girder under the most stress [20][21][22]. The parameters that condition the calculation of the LDF are the girder depth, span length, spacing, the number of girders, the position of the load, and the girder position.…”

Section: Figure 1 Grillage Discretization: (A) Girder Bridge Deck Cro...mentioning

confidence: 99%

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Novel Method for an Optimised Calculation of the Cross-Sectional Distribution of Live Loads on Girder Bridge Decks

Gaute-Alonso

Calderon-Uriszar-Aldaca

Castillo

2022

Civ Eng J

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One of the main goals in the design of girder bridge deck systems is to determine the cross-sectional distribution of live loads across the different girders that make up the cross-section of the deck. Structural grillage models and current bridge design standards based on a Load Distribution Factor (LDF) provide oversized designs, as demonstrated in this paper. This research introduces a novel method that allows the cross-sectional distribution of live loads on girder bridge decks to be calculated by applying a matrix formulation that reduces the structural problem to 2 degrees of freedom for each girder: the deflection and the rotation of the deck-slab at the centre of the girder’s span. Subsequently, a parametric study is presented that analyses the structural response of 64 girder bridge decks to a total of 384 load states. In addition, the authors compare the outputs of the novel method with those obtained using traditional grillage calculation methods. Finally, the method is experimentally validated on two levels: a) a laboratory test that analyses the structural response of a small-scale girder bridge deck to the application of different load states; b) a real full-scale girder bridge load test that analyses the structural response of the bridge over the Barbate River during its static load test. Based on this analysis, the maximum divergence of the proposed method obtained from the experimental structural response is less than 10%. The use of the proposed novel analysis method undoubtedly provides significant savings in material resources and computing time, while contributing to minimizing overall costs. Doi: 10.28991/CEJ-2022-08-03-01 Full Text: PDF

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Section: Discussionmentioning

confidence: 99%

Section: Figure 1 Grillage Discretization: (A) Girder Bridge Deck Cro...mentioning

confidence: 99%

Novel Method for an Optimised Calculation of the Cross-Sectional Distribution of Live Loads on Girder Bridge Decks

Gaute-Alonso

Calderon-Uriszar-Aldaca

Castillo

2022

Civ Eng J

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“…The results of studies carried out by Hughs & Idriss [13] showed that LLDFs calculated by the equations given in AASHTO are conservative compared to the results of FE analyses. More recently, research on LLDF has considered specific bridge systems with longitudinal beams [14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

A New Proposal for Live Load Distribution Factors of Bridges with Transverse Beams

Abrishamkar¹,

Kholghi²,

Maleki³

2022

J. Civ. Eng. Constr.

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Many bridge superstructures use transverse beams as load carrying components. In these systems, usually the transverse beams are connected to the main longitudinal girders or trusses on the two sides of the bridge. Such systems are commonly used in plate girder, box girder, cable-stayed and truss bridges. The live load distribution factor (LLDF) for bridge superstructures with transverse beams in AASHTO-LRFD bridge design specification has remained unchanged for decades and is prescribed as a function of the distance between the transverse beams. However, for slab-beam superstructures in which longitudinal beams at close spacing carry the loads to the substructure, the LLDFs have gone through many changes throughout the years and in their current forms depend on many parameters such as concrete slab thickness, beam span, longitudinal beam stiffness as well as the distance between the longitudinal beams. This study investigates the factors affecting the LLDF for transverse beams and intends to obtain new equations similar to AASHTO’s longitudinal beam equations. For this purpose, 3D finite element models of different sample bridges were developed and critical parameters affecting the LLDF were identified and varied. Accordingly, the LLDFs for moment and shear forces of transverse beams were obtained through regression analyses. The proposed equations have less than 3.1% of average error for the cases considered.

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“…For instance, a cumulative distribution function of the DAF was developed. 15,16 An assessment dynamic ratio (ADR) was developed to define the relationship between the characteristic dynamic traffic load effect and the characteristic static traffic load effect in a reference period. 17 Subsequently, the ADR was utilized as a lifetime dynamic allowance value to investigate the dynamic impact of traffic loading on short-to-medium span concrete bridges.…”

Section: Introductionmentioning

confidence: 99%

Probabilistic evaluation of maximum dynamic traffic load effects on cable-supported bridges under actual heavy traffic loads

Liu

Wang

2020

Proceedings of the Institution of Mechanical Engineers, Part O:

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The traffic load has grown significantly in recent years, which might be a threat for the service safety of existing bridges. Thus, it is an urgent task to assess the actual traffic load effects on bridges, considering actual heavy traffic load instead of design traffic load. This study presents a framework for extrapolating maximum dynamic traffic load effects on large bridges using site-specific traffic monitoring data. The framework involves vehicle–bridge interaction analysis and probabilistic modelling of extreme values. The weigh-in-motion measurements of a busy highway in China were collected for stochastic traffic load modelling. Case studies of two long-span cable-supported bridge based on the weigh-in-motion measurements were conducted to demonstrate the effectiveness of the proposed framework. It is demonstrated that Rice’s level-crossing approach can capture both dynamic and probabilistic characteristics of the traffic load effects. The root-mean-square displacement of the cable-stayed bridge follows a C-type distribution, and the one for the suspension bridge follows an M-type distribution, which is associated with the first-order mode shapes of the two types of bridges. The amplification factors for the cable-stayed bridge and the suspension bridge are 5.9% and 3.6%, respectively. The numerical analysis indicates that the dynamic effect for extrapolation is weaker with the increase in bridge span length, but the effect of traffic volume growth will be more significant.

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Experimental and Analytical Investigation of Live-Load Distribution Factors for Double Tee Bridges

Cited by 7 publications

References 21 publications

Novel Method for an Optimised Calculation of the Cross-Sectional Distribution of Live Loads on Girder Bridge Decks

Novel Method for an Optimised Calculation of the Cross-Sectional Distribution of Live Loads on Girder Bridge Decks

A New Proposal for Live Load Distribution Factors of Bridges with Transverse Beams

Probabilistic evaluation of maximum dynamic traffic load effects on cable-supported bridges under actual heavy traffic loads

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