Spatial and Temporal Load Distribution in Steel Bridge Superstructures (Vol. II): Evaluation of Skewed Steel I-Girder Bridge Behavior under Deck Placement and Live Load through Field Monitoring and Numerical Simulation

Zhou, Siang; Dorado, Ricardo; Fahnestock, Larry; LaFave, James

Permalink

https://hdl.handle.net/2142/133188 Copy

Description

Title

Spatial and Temporal Load Distribution in Steel Bridge Superstructures (Vol. II): Evaluation of Skewed Steel I-Girder Bridge Behavior under Deck Placement and Live Load through Field Monitoring and Numerical Simulation

Author(s)

• Zhou, Siang
• Dorado, Ricardo
• Fahnestock, Larry
• LaFave, James

Issue Date

2026-05

Keyword(s)

• Skewed Bridge
• Steel I-Girder Bridge
• Flange Lateral Bending
• Field Monitoring
• Numerical Simulation
• Deck Placement
• Live Load

Date of Ingest

2026-05-08T15:17:42-05:00

Abstract

Two skewed (around 45°) two-span continuous bridges with stub abutments or integral abutments were monitored in the field during construction and after the bridges were in service. The goal was to establish a comprehensive understanding of load distribution in skewed steel I-girder bridges and to potentially refine their analysis and design procedures. Key girder cross-sections and cross-frames were instrumented with strain gauges, and global bridge movements were captured with displacement transducers and tiltmeters. Temperature was recorded simultaneously with structural response measurements. Numerical studies using 3D finite element analysis (FEA) were based on a field-validated simulation framework. The 3D FEA was conducted on the instrumented bridges to evaluate effects of bridge geometry, especially skew and abutment type, on skewed steel I-girder bridge superstructure response. Load distribution during deck placement and under live load was investigated, and standard design guidelines regarding girder strong-axis bending and flange lateral bending were evaluated. For a skewed bridge with a staggered cross-frame layout along its length under concrete dead load, standard design recommendations from the AASHTO “LRFD Bridge Design Specifications” regarding skew-related lateral bending stress might not be appropriate for both interior and exterior girders. Under isolated truck live loads, exterior girders are prone to larger strong-axis bending stress than interior girders when directly loaded, while interior girders are more critical regarding flange lateral bending stress than exterior girders. Distribution of lateral bending stress on a skewed bridge is dependent on the live load position, and limiting the distance between the first intermediate cross-frame and bridge ends is important to avoid lateral bending stress concentration near bridge obtuse corners. The dynamic load allowance of 33% used in design was found to be mostly conservative, except at a few monitored locations near obtuse corners of the integral abutment bridge.

Publisher

Illinois Center for Transportation/Illinois Department of Transportation

Has Part

ISSN: 0197-9191

Series/Report Name or Number

FHWA-ICT-26-005

Type of Resource

text

Genre of Resource

technical report

Language

eng

DOI

https://doi.org/10.36501/0197-9191/26-005

Sponsor(s)/Grant Number(s)

IDOT-R27-194

Copyright and License Information

No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161.

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