Distribution of live load shears in FRP composite tub girder highway bridges

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures Pub Date : 2024-10-30 DOI:10.1016/j.engstruct.2024.119188

Jon Pinkham , William G. Davids , Andrew Schanck , Keith Berube

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引用次数: 0

Abstract

In the design of slab-on-girder highway bridges consisting of conventional materials like concrete and steel in the United States, the vehicular live load carried by a single girder is calculated using distribution factors (

DF

s) defined in the American Association of State Highway and Transportation Officials (AASHTO) design specifications. However, shear

DF

s for the recently developed fiber reinforced polymer composite tub (CT) girder do not exist within current design codes, and to-date in-service CT girder bridges have been designed using AASHTO shear

DF

s for concrete box girders. To assess shear live load distribution in CT girder bridges, diagnostic live load tests were performed on two in-service highway bridges under heavy truck loads. High-fidelity finite element (FE) models calibrated to the test results were simplified to reflect conventional design assumptions. The high-fidelity FE models indicated that AASHTO over-predicted live load shears in the most heavily loaded interior girder by as much as 35 %, but can under-predict exterior girder live load shear. Parametric studies using the simplified FE models indicated that while the most influential parameter on CT girder shear

DF

s is girder spacing, girder bottom flange width can also play a significant role. The simulations and diagnostic live load tests both indicate that the AASHTO shear

DF

expressions for concrete box, slab-on-girder bridges that are currently used in CT girder design typically over-predict shear

DF

s for interior CT girders. Simulations with the simplified model indicate over-predictions of

DF

s for interior CT girders of up to 30 % for longer spans and large girder spacing. However, in the CT girder that experienced the greatest shear strain during field load testing, measured strains in the most heavily loaded web were 22 % higher than the average girder web shear strain, a factor not currently accounted for by existing AASHTO DFs or in CT girder design.

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FRP 复合材料管梁公路桥活载剪力的分布

在美国，由混凝土和钢等传统材料组成的梁上板公路桥的设计中，单根梁所承受的车辆活荷载是通过美国州公路与运输官员协会（AASHTO）设计规范中定义的分布系数（DFs）来计算的。然而，在当前的设计规范中并没有针对最近开发的纤维增强聚合物复合管（CT）梁的剪力分布系数，迄今为止，使用中的 CT 梁桥都是采用 AASHTO 针对混凝土箱梁的剪力分布系数进行设计的。为了评估 CT 梁桥的剪切活荷载分布，对两座重型卡车荷载下的在役公路桥进行了诊断性活荷载试验。根据测试结果校准的高保真有限元 (FE) 模型经过简化，以反映常规设计假设。高保真有限元模型表明，AASHTO 对荷载最重的内部梁的活载剪切力预测过高达 35%，但对外部梁的活载剪切力预测不足。使用简化 FE 模型进行的参数研究表明，虽然对 CT 梁剪切 DF 影响最大的参数是梁间距，但梁底部翼缘宽度也能发挥重要作用。模拟和诊断活载试验均表明，目前 CT 梁设计中使用的 AASHTO 混凝土箱梁、梁板桥剪力 DF 表达式通常会过高预测 CT 梁内部的剪力 DF。简化模型的模拟结果表明，在跨度较大、梁间距较大的情况下，CT 梁内部的 DF 预测过高可达 30%。然而，在现场荷载测试中经历了最大剪应变的 CT 梁中，荷载最重的腹板中的测量应变比平均梁腹板剪应变高出 22%，而现有的 AASHTO DF 或 CT 梁设计中并未考虑这一因素。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Engineering Structures 工程技术-工程：土木

CiteScore

10.20

自引率

14.50%

发文量

1385

审稿时长

67 days

期刊介绍： Engineering Structures provides a forum for a broad blend of scientific and technical papers to reflect the evolving needs of the structural engineering and structural mechanics communities. Particularly welcome are contributions dealing with applications of structural engineering and mechanics principles in all areas of technology. The journal aspires to a broad and integrated coverage of the effects of dynamic loadings and of the modelling techniques whereby the structural response to these loadings may be computed. The scope of Engineering Structures encompasses, but is not restricted to, the following areas: infrastructure engineering; earthquake engineering; structure-fluid-soil interaction; wind engineering; fire engineering; blast engineering; structural reliability/stability; life assessment/integrity; structural health monitoring; multi-hazard engineering; structural dynamics; optimization; expert systems; experimental modelling; performance-based design; multiscale analysis; value engineering. Topics of interest include: tall buildings; innovative structures; environmentally responsive structures; bridges; stadiums; commercial and public buildings; transmission towers; television and telecommunication masts; foldable structures; cooling towers; plates and shells; suspension structures; protective structures; smart structures; nuclear reactors; dams; pressure vessels; pipelines; tunnels. Engineering Structures also publishes review articles, short communications and discussions, book reviews, and a diary on international events related to any aspect of structural engineering.