September 14, 2022 - 8:00am to 12:00pm

 

Cross-frames and diaphragms are important steel bridge components as they provide stability to primary longitudinal girders and improve lateral or torsional stiffness and strength of the bridge system during construction and in-service.   In horizontally curved bridges they transfer forces between adjacent girders to provide equilibrium; and in straight bridges they have been historically designed to transmit wind loads.

Over the last few years, the steel bridge industry has seen a general increase in the size of cross-frames used in steel I-girder bridges across the country, in terms of both the individual member sizes and the connections themselves, resulting in significant inefficiencies. On a cost per pound basis, the cost to fabricate cross-frames can be the most expensive part of any steel girder bridge project. 

This workshop will review the design history of cross-frames, and then provide guidance to designers so that they can make better choices regarding cross-frame layouts, type, members, connections as well as loads, analysis, and design.  The workshop will walk through design decisions for cross-frames in bridges that are straight with low skew, straight andheavily skewed, and horizontally curved with skewed supports.  For each bridge type the following topics will be presented: efficient cross-frame and framing plan layout decisions, analysis considerations, stability requirements, design loads, member design, and connection design.  Fabrication techniques for cross-frames and diaphragms will also be discussed, explaining why certain decisions will result in more efficient fabrication of cross-frames.

Program

8:00 AM

Introductions and Basics of Cross-frames and Diaphragms, Q&A

9:00 AM

Fabrication of Cross-frames and Diaphragms, Q&A

9:45 AM

Example – Straight Bridge with no Skew, Q&A

10:15 AM

15-minute break

10:30 AM

Example – Straight Bridge with Skew, Q&A

11:15 AM

Example – Curved Bridge with Skew, Q&A

11:45 AM

Wrap up and any additional Q&A

Noon

Adjourn

 

Learning Objectives:

  • Attendees will be able to recognize the basic functions of cross-frames and diaphragms in steel girder bridges.
  • Attendees will be able to describe the cross-frame fabrication process.
  • Attendees will be able to recognize the necessary design loads for cross-frame design in straight bridges without skewed supports.
  • Attendees will be able to describe advantageous framing plan options for cross-frames and girders in bridges with horizontal curvature and skewed supports.
     

Registration

Early Bird (before 8/14/2022)
  • Member - $185.00
  • Nonmember - $235.00
     

Regular Registration Rates (effective 8/14/2022)

  • Member - $235.00
  • Nonmember - $285.00
     

Location

Association Forum 
10 S Riverside Plaza, Ste. #800
Chicago, IL 60606
 

About the Speakers

Brandon Chavel PE, PhD 
Michael Baker International
Brandon Chavel is a Great Lakes Region Bridge Technical Manager for Michael Baker International as is located in Cleveland, Ohio.  He has over 20 years of experience in the bridge industry, with significant experience in the analysis, design, fabrication, and construction of steel bridges. Brandon earned his B.S., M.S., and Ph.D. in Civil Engineering from the University of Pittsburgh.  He is a registered Professional Engineer in several states. Brandon is engaged in several national professional organizations, including serving as chair of the Design Task Group for the AASHTO/NSBA Steel Bridge Collaboration and co-chair of the TRB subcommittee AKB20(1), Analysis of Steel Bridges.
 

Devin Altman, PE
National Steel Bridge Alliance
Devin Altman is a Bridge Steel Specialist in the Steel Solutions Center for the National Steel Bridge Alliance, a division of the American Institute of Steel Construction. Devin's role with NSBA is to provide technical assistance, tools, and resources for steel bridge owners, designers, fabricators, university programs, and technical committees. Prior to joining NSBA 2.5 years ago, Devin spent over 15 years in the bridge consulting profession as a bridge engineer and project manager, with the previous 12 years at CH2M Hill/Jacobs working on a wide range of projects. His bridge project experience includes design, load ratings, rehabilitation, complex analysis, and construction of a wide variety of structure types located throughout the USA and Internationally. Devin earned his B.S. in Mathematics from The Evergreen State College, a Master of Engineering degree in Structural Engineering and Construction Engineering Management from Oregon State University, and is a registered Professional Engineer in Oregon. 
 

Ronnie Medlock, PE
High Steel Structures, LLC
Ronnie is a registered professional engineer and is VP - Technical Services at High Steel Structures, LLC, a steel bridge fabricator in Lancaster, Pennsylvania. At High Steel, Ronnie oversees quality control and fabrication and inspection technology development and implementation. Ronnie joined High Steel in 2006; prior to that, he worked for TxDOT in materials (1988 to 2001) and then structures design (2001 to 2006). Ronnie is engaged with several national bridge trade and professional organizations, including serving as chairman of the NSBA Technical Committee.

 

 

 
 
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Participants

Ryan Negangard ( IDOT BBS )
PETER PASCUA ( Illinois Department of Transportation )
Karen Yung ( Primera Engineers Ltd. )
Ben Christmann
Chaohui Li ( Lin Engineering, Ltd. )