Natasha Butler, P.E., State Bridge Engineer, Colorado DOT
Keely Matson, P.E., Department Manager – Bridge, Michael Baker International
Francisco Javier Bonachera Martin, Ph.D., P.E., Visiting Associate Professor, School of Civil and Construction Engineering, Purdue University

Presentation begins: 06:58
Q&A begins: 42:45

Documents:
March Presentation Blue Mesa
March News & Intro

Description:
In April 2024, while conducting the FHWA required non-destructive evaluation of Non-Redundant Steel Tension Member (NSTM) bridges, CDOT discovered two partial fractures at the shop butt welds along the bottom tension flange of the US-50 Blue Mesa Reservoir Bridge near Gunnison, Colorado. CDOT immediately closed the structure to prevent bridge failure.  This closure resulted in a lengthy six-hour detour for local motorists.  Emergency work with CMGC industry partners Kiewit Infrastructure Company and Michael Baker International began immediately to identify and implement solutions to repair or replace the critical bridge and its partner bridge. Non-destructive testing revealed additional fractures and widespread transverse hydrogen cracking of the girders. The CMGC team, in collaboration with Dr. Rob Connor, Ph.D., P.E. and the S-BRITE research group at Purdue decided to implement global plating of the bottom tension flanges as well as implementing the use of a novel approach consisting of a pattern of holes that would attract and arrest a travelling crack and thus deter the propagation of cracking through the web.  Critical repairs were completed in July of 2024, to allow limited traffic back on the bridge.  Complete structural repairs were completed in December 2024.

Presenters:

Introduction by:
Natasha Butler, P.E.
State Bridge Engineer
Colorado DOT

Keely Matson, P.E.
Department Manager – Bridge
Michael Baker International

Francisco Javier Bonachera Martin, Ph.D., P.E.
Visiting Associate Professor
School of Civil and Construction Engineering
Purdue University

Presentation Photos/Graphics:

1) Bridges originally opened in 1963

4) Local splice plating was used to repair the top flange butt welds

5) The "plinko plate"  protects against future cracks in the web-to-flange welds

6) Both bridges were reopened by December 2024 to two-way traffic with no load restrictions