PROJECT PROFILE  

FatigueWatch EFS Installation on Bridge #9090 Over Red River in Grand Forks, MN with MNDOT 

 Situation Metal Fatigue Solutions (MFS) worked with MNDOT as part of a cooperative                       agreement to perform dynamic testing inspections on Bridge #9090 US 2 over                       Red River of the North between District 2 East Grand Forks, Polk County,                         Minnesota and Grand Forks, Grand Forks County, North Dakota. Bridge No.                     9090 consists of two truss spans and eleven approach spans.   

The Electrochemical Fatigue Sensor­based FatigueWatch system is being used                 to determine the presence of         growing cracks at selected       locations on the East Span         South Side L­1/2 Gusset. A         total of 4 locations were         selected: 3 different Fillet       Weld Gusset Plate to built­up         Lower Truss Chord locations       (2 Corner welds and 1 Vertical           weld (at upper weld       termination) for Gusset Plate       to built­up Lower Truss Chord)         and 1 Plug Weld Gusset Plate           to built­up Lower Truss Chord         

Location, adjacent to plug weld previously identified with Magnetic Particle                   Inspection and repaired. Access was provided by a MNDOT Aspen A­62 Under                       Bridge Inspection Unit operated by MNDOT personnel to install 2 each sensors                       per location. All the inspection locations were chosen in collaboration with                     

MNDOT.  

Installation of the FatigueWatch system was the first of its kind – a long­term                           fatigue crack monitoring system that is location specific. The system is intended                       to monitor known and susceptible locations for active fatigue cracking as well as                         determine the approximate rate of growth. Different from MFS’s inspection                   system, FatigueWatch can monitor the growth activity in extreme conditions. In                     fact installation of the system occurred during ­11 degree Fahrenheit wind chill                       conditions. The system incorporates a NEMA enclosure for the electronics as                     well as Verizon communications for immediate access to live data. 

 Overall Conclusions and Findings The inaugural field installation of the EFS             FatigueWatch System was a success. It is collecting               & streaming data and is currently being monitored at                 our St George, Utah facility with no interruption. It                 will be utilized to determine the crack growth activity                 of all selected inspection locations on MNDOT             District 2 Bridge #9090, Polk County, MN. The data                 used in the analysis is being collected while all lanes of the bridge are open to                               ambient traffic and weather conditions.  

PROJECT PROFILE