SEI OC - Steel Bridge Redundancy

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Lunch will be served, vegetarian options available with registration

Revisiting Redundancy of Steel Bridges

Two AASHTO Guide Specifications were released at the end of 2018 with 2022 interims. They offer the analytical framework needed to revisit the way we evaluate redundancy in steel bridges considering system level and member level redundancy for new or existing bridges. For the last four decades, the steel bridge industry has become accustomed to determining redundancy through engineering judgement married to a single approach, namely load path redundancy (referring to the number of girder lines).

Publication of these Guide Specifications enables designers and owners to design outside the box that we put ourselves in 40 years ago. In addition, The Guide Specifications also include a methodology to establish a risk-based inspection interval for a special inspection of internally redundant members (IRMs) that is of sufficient depth to reliably detect a severed component. This is a major departure from the conventional calendar-based approach of setting inspection intervals and is a forward step in developing an integrated fracture control plan by AASHTO.

This presentation will gather perspective from the aviation industry to discuss the development of these AASHTO Guide Specifications in the context of historical AASHTO fracture control approaches. It will explore the research behind the new guide specifications, suggested implementation congruent with the 2022 NBIS, and help the audience further understand the value of integrating the fracture control plan in this way while revisiting concepts in redundancy of steel bridges.

Jason B. Lloyd, PhD, PE, Manager of Bridge & Infrastructure Solutions, Nucor

Dr. Lloyd is a licensed professional engineer currently working as the Manager of Bridge & Infrastructure Solutions at Nucor where he is partnering with fabricators, owners and designers for project success. He has 18 years of professional experience in marketing, training, and public speaking, large scale research, infrastructure monitoring, and contract and construction management.

He attained his MS and PhD Civil Engineering (Structures) from Purdue University. Prior to joining Nucor, Jason worked for the National Steel Bridge Alliance (NSBA) promoting the design and construction of steel bridges through marketing, education, and technical collaboration efforts.

Before the NSBA, Jason was a research engineer at Purdue University specializing in field testing and remote long-term and short-term monitoring of structures, data acquisition over remote communications, large scale fatigue & fracture research, bridge inspection research, steel bridge repair and retrofit, and steel bridge redundancy.

Prior to university, Jason proudly served in the US Navy Civil Engineer Corps where he managed construction contracts with multi-national contractors using design-bid-build and design-build delivery methods. He was awarded the Navy Commendation Medal, Navy Achievement Medal, and the Iraqi Campaign Medal.

Jason currently serves on several technical committees, research technical advisory groups and collaborations, and is the vice chair for the National Steel Bridge Alliance Executive Council.