Evaluation of Superstructure Response and Load Distribution in Skewed Steel I-Girder Bridges

Highly-skewed steel I-girder bridges are commonly used, especially in congested areas, despite complications in their analysis, design, and construction. Although design requirements (such as the commonly used line girder analysis) have guidelines associated with skew, more study is needed to establish a comprehensive understanding of load distribution in skewed steel I-girder bridges and to potentially refine the associated analysis and design procedures.

This presentation discusses field monitoring and 3D finite element analysis of two bridges in the vicinity of each other in Champaign, Illinois, to provide new understanding of skew effects on bridge superstructure behavior during construction and after in-service. Mattis Avenue over I-74 (Mattis-74) and Mattis Avenue over I-57 (Mattis-57) are both two-span continuous bridges using cross-frames in a staggered layout throughout the bridges. Mattis-74 is a stub abutment bridge with 41° skew, and Mattis-57 is an integral abutment bridge with 45° skew. The Mattis Avenue bridges were instrumented with sensing equipment capable of high sampling frequency (up to 20 Hz), to measure strain gauges at key girder cross-sections and cross-frames; end rotations of critical girders were measured with tiltmeters, global bridge movements were captured with displacement transducers, and temperature was simultaneously recorded with the structural response measurements.

Data collection was initiated during construction, and the instrumented bridges were evaluated in the field during deck placement and after each bridge was in service through truck tests at various speeds – 3 kph (2 mph), 32 kph (20 mph), and 56 kph (35 mph). 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.

1 hour of CE credit

Learning Objectives

• Familiarize the audience with current standard practice to design and analyze skewed steel I-girder bridges, including calculation of strong-axis bending and flange lateral bending stress during construction and after in-service.
• Understand lateral bending behavior of skewed steel I-girder bridges during deck placement and learn about the limitations of the commonly used line girder analysis.
• Understand load distribution on skewed steel I-girder bridges under truck live loads and learn about the accuracy of AASHTO specifications regarding the estimation of girder strong-axis bending and flange lateral bending stress.

Registration

Members: $25
Nonmembers: $45

This is a virtual event on Zoom. Attendees are required to have a free Zoom account in order to have access to the webinar.

About the Speaker

Siang (Sunny) Zhou, Ph.D.
Department of Civil Engineering - University of Texas Rio Grande
Dr. Sunny Zhou is an Assistant Professor at the University of Texas Rio Grande Valley, in the Department of Civil Engineering. Prior to joining UTRGV in 2023, she spent eight years at University of Illinois Urbana-Champaign for her Master and Doctoral study, where she was the leading graduate student on the ICT project of interest today for about five years since 2018. Dr. Zhou is interested in research that is broadly related to design, performance, and monitoring of infrastructure, spanning across bridges, railroads, and buildings. Her research focuses on improving design efficiency and structural resilience of infrastructure; related work involves evaluating performance of structural systems under various load conditions through large-scale testing and numerical simulations, as well as health monitoring of existing structures. Dr. Zhou is a reviewer for multiple ASCE journals, including Journal of Bridge Engineering and Journal of Performance of Constructed Facilities; she is awarded the ASCE Outstanding Reviewer in 2022 by Practice Periodical for Structural Design and Construction. She is an active member of TRB committee on Railroad Operating Technologies and subcommittee on Bridge Life Cycle Cost Analysis. Dr. Zhou is the Director at Larger for the ASCE Texas Section for the current term.