Wednesday, September 21, 2022 from 5:00 PM to 7:00 PM CDT
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311 S. Wacker Drive
Chicago, IL 60606

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Justin Mickens 
SEI-Illinois Chapter 

SEI - IL SEPTEMBER DINNER MEETING: Case Studies in Evaluating Redundancy in Existing Steel Bridges 

Presented by Irsilia Colletti

Join the Structural Engineering Institute – Illinois Chapter for a presentation by Irsilia Colletti on “Case Studies in Evaluating Redundancy in Existing Steel Bridges.”

The presentation will cover four case studies in which existing steel bridges were evaluated as to their fracture critical designation, in particular if system redundancy can be demonstrated through sophisticated non-linear analyses and the application of criteria established in NCHRP Report 406. The investigation of redundancy includes developing detailed FEM models and member capacities upon which to compare demand. In locations where system redundancy is determined to not be present through alternate load paths, repairs to provide system or member redundancy are developed to reduce the risk of fracture critical failure. While addressing redundancy, the project aims to also extend the bridge service life through painting and repair recommendations. Details of the bridges, the redundancy evaluation through the application of linear and non-linear FEM using Larsa4D as the prime modeling tool, as well as CSI Bridge fully independent analyses, and structural recommendations are included. In addition, some retrofitting details were reviewed utilizing LUSAS.

Irsilia Colletti PE, SE, has worked at HNTB full time since starting as a bridge engineer over 10 years and currently acts as a Project Engineer in the Bridge Structures Department. Irsilia has worked on a wide spectrum of projects from culverts and sign structure evaluations to complex signature bridges as both a designer and reviewer. She was selected as last year’s ASCE Illinois Young Engineer of the year and is an acting director of ASCE Illinois section.