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Inspecting Steel Bridges for Fatigue

INDOT Logo  Currently required by INDOT for complex and fracture-critical bridge inspection qualification.

Course brochure (Hosted at Purdue): Inspecting Steel Bridges for Fatigue (PDF)

Course brochure (Hosted at your location): Inspecting Steel Bridges for Fatigue (PDF)

When cracks are discovered on bridges in service, fatigue is usually the cause.  A working knowledge of fatigue susceptible details, AASHTO fatigue categorization, and NDE methods and limitations is essential to the proper inspection of both new and in-service steel structures.  

This course will focus on fatigue and fracture from the point of view of inspectors and fabricators.  Topics will be focused on steel highway and railroad bridges of all types.  Other topics will include: fatigue and fracture performance of steel bridges which have been damaged by impact and subsequently heat straightened; Constraint-Induced Fracture (“Hoan Details”) – identification and retrofit; and fabrication flaws will be presented. 

Special attention will be given to identifying details which are sensitive to fatigue, prioritizing details for inspection, and where to expect cracking.  In addition, NDT techniques such as UT, dye penetrant, and magnetic particle testing will be presented.  Guidance on when and why to select a specific type of NDT will also be discussed.  Effective and ineffective retrofit strategies for steel bridges will also be presented. 

The course will utilize several case studies for illustrative purposes and when hosted at Purdue University will include a hands-on practicum, as well.

This course is currently required by Indiana DOT for fracture-critical and complex bridge inspections.

Meet the Instructors


Robert Connor, Ph.D., is an associate professor of civil engineering at Purdue University and Director of the Steel Bridge Research, Inspection, Training, and Engineering (S-BRITE) Center.  Dr. Connor is nationally recognized as an expert in fatigue and fracture of steel bridges and sign structures.


Philip Fish, C.W.I., is nationally recognized for his experience in fracture and fatigue analysis, nondestructive testing and inspection (Level III certifications), strain gauging, weld inspections, steel connection details, forensic analysis of steel structures, and developing comprehensive quality assurance programs for large scale structural steel fabrication.  He conducts multiple seminars and courses nationally each year on bridge inspection methods, fracture critical bridge structures, and structural steel welded and bolted connections.

Jason B. Lloyd, PE, is a Research Engineer at the S-BRITE Center at Purdue University and Robert L. and Terry L. Bowen Laboratory for Large Scale Civil Engineering Research.  Mr. Lloyd has performed numerous field instrumentation, laboratory, and fitness-for-service studies on various steel bridge types.  He specializes in full-scale testing, field monitoring, fatigue evaluation, fracture, and repair and retrofit of steel bridges.  

Learning Objectives

• Be able to identify and prioritize critical fatigue prone details;

• Be able to recognize details susceptible to fatigue cracking due to secondary stresses and out-of-plane distortion. 

• Be able to recognize potential fatigue problems which may occur in special situations such as curved bridges, skewed bridges, anchor bolts and sign structures;

• Be able to recognize and understand issues arising during fabrication as related to material, fracture toughness, defects, shop/field repairs, mill scale, tack welds, etc.;

• Understand differences in redundant and non-redundant bridges;

• Be familiar with the most common forms of NDT;

• And identify details susceptible to constraint induced fracture (CIF)

Participants will receive hands-on experience in the inspection course implementing training received in the classroom.

Agenda for course held at S-BRITE Center (Purdue)

Day 1

8:00 - Introduction and Welcome / Course Announcements

8:05 - Background
(What is fatigue and what is fracture?  What is a stress range cycle?)

8:50 – Fatigue Susceptible Details
(Where are cracks expected to initiate? Examples of details that are susceptible to fatigue)

9:35 – Fracture Susceptible Details
(Examples of details that are susceptible to fracture; case studies)

10:35 - Break

10:50 – Non-Destructive Testing Methods
(Techniques, applications, and limitations of several NDE methods)

12:00 - Lunch 

1:00 – Secondary Stresses
(Distortion-induced fatigue)

1:40 – Hands-on exercises
       Group 1 - NDE exercises                                           Group 2 - Inspection exercises

2:45 - Break

3:00 – Hands-on exercises
       Group 1 - Inspection exercises                                 Group 2 - NDE exercises 

4:05 – Review of day 1

4:30 – Adjourn Day 1

Day 2

8:00 –  Inspection of gusset plates for fatigue

8:30 – Welding fundamentals
(Inspection for fatigue, defects, shop/field repairs, etc.)

9:15 – Issues with impact damage

9:45 - Retrofit (Fatigue and fracture retrofit strategies)

10:15 – Break

10:30 – Variability in NDE data
(Performance testing of inspectors, case studies considered)

11:00 – Discussion and questions

11:15 – Exam

12:00 - Adjourn

Agenda for course held out-of-state at your facility

(not offered for INDOT inspection qualifications)

Morning Agenda

8:00 - Introduction and Welcome / Course Announcements
(Robert J. Connor / Phil Fish)

8:05 - Background
(What is fatigue and what is fracture?  What is a stress range cycle?)

8:40 – Fatigue Susceptible Details
(Where are cracks expected to initiate? Examples of details that are susceptible to fatigue)

9:10 – Fracture Susceptible Details
(Where are cracks expected to initiate? Case studies.)

9:50 - Break

10:00 – Non-Destructive Testing Methods
(Techniques, applications, and limitations of several NDE methods)

10:40 – Secondary Stresses
(Distortion-induced fatigue)

11:25 – Group 1 - NDE exercises
              Group 2 - Lunch

12:25 – Group 1 - Lunch
              Group 2 - NDE exercises

 

Afternoon Agenda

1:30 – Inspection of gusset plates for fatigue

2:00 – Welding fundamentals                                  (Inspection for fatigue, defects, shop/field repairs, etc.)

2:40 – Issues with impact damage

3:20 – Break

3:30 - Retrofit
(Fatigue and fracture retrofit strategies)

3:50 – Variability in NDE data
(Performance testing of inspectors, case studies considered)

4:10 – Discussion and questions

4:15 – Exam

5:00 - Adjourn