· ... Standard Specifications for Structural Supports for Highway ... Structural Supports for Highway Signs, ... Evaluation of Overhead Support Inspection Program

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Ancillary Structures

Presented by Chace Hulon2018 Transportation Conference

February 28, 2016

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1. Introduction to the Program

2. Raise Awareness

GOALS

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1. Ancillary Program – Overview

2. LADOTD – We’re on the map

3. Failure – NOT an option

OUTLINE

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FHWA produced guidelines for Ancillary structures in March 2005.

Ancillary Program - Overview

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Types of ancillary assets:

• Highway Signs, Luminaires and Traffic Signals

• Bridge mounted signs

• Bridge mounted utility structures

• Pedestrian bridges

• Large non-qualifying culverts

• Retaining walls

• Sound barriers

• Privately owned structures open to public access

• Tunnels


. . . . .Overhead Sign Structures (OSS): structural elements designed to carry signs over the roadway and are attached to a designed foundation.






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Personnel qualifications and training

• Program Manager:

– LA PE with approved NHI training

• Inspection Team Leader:

– 5 yrs experience with approved NHI training

• Visual weld inspection experience

• Fatigue cracking (aluminum and steel) experience and training

• Fall protection training, rope access training

• Work zone traffic control safety training

• Ultrasonic flaw detection training

“In combination with the Bridge Inspection Program, a safe and reliable roadway infrastructure is only achievable through the direct efforts of the Inspector.” VDOT


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Inspection Types:

• Initial, Routine, In-Depth, Interim, Damage

Frequencies:


Material Structure Type

Rating Frequency(Months)

Steel Span 5-9 72

Aluminum Span 5-9 48

All Cantilever 5-9 48

All All 4 12

All All 3 6

All All 2 3

. . . . .Equipment

• Hammer

• Wrenches

• Level

• Stencils and paint

• Markers, paint pens, and flagging tape

• Tablet

• Camera and radios

• Rulers and electronic distant meters

• Bucket truck and fall protection PPE equipment


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NDT Equipment

• Ultrasonic Flaw Detector

• Dye Penetrant / Mag Particle


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Traffic Control

• Portable signs, cones, 360˚ high intensity light and strobes, MUTCD


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Best Safe Practices

Safety

• Pre-plan hazard analysis and mitigation

– Traffic Control

– Fall Protection / Rope Access

• Rescue plan with emergency contacts

• 2-man teams with specific training

• Equipment knowledge

• Understanding of personal limits

• Safety committee oversite


Communication

• Kickoff meetings with owner of the program

• Regular team meetings

• Local meetings with area engineers

• On-site meetings prior to field operations

• Critical finding contact protocol

• Responsiveness

• Post inspection categorization

• Post work debrief meeting

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OUTLINE

. . . . .LADOTD – We’re on the map

M&N hired 2.5 years ago

9/2015 – 2/2018

• 1351 Initial Inspections

• 97 Interim Inspection

Districtwide approach

ArcGIS file

• Control section

• Logmile

. . . . .LADOTD – We’re on the map

Inventory Management System

• Custom Application

Bypassed Lane Closures

• 2% will require a lane closure

. . . . .Fall Protection • “Although bucket trucks are typically used to access the sign bridge, an adequate in-

depth inspection cannot be fully performed from the bucket and some climbing will be required” FHWA Guidelines

• INDOT Memo, 9/21/2015 - Adopted the practice of climbing over lanes open to traffic vs. closing lanes and altering normal flow of traffic.

• Safer to avoid using traffic-control devices

• Efficiency

LADOTD – We’re on the map

. . . . .Fall Protection• To assess the current Ohio DOT program, a detailed, hands-on

inspection was conducted on 202 supports. The results were then compared with the Ohio DOT’s current ground-based, visual inspection process. The hands-on inspection process found almost 87% more deficiencies; some deficiencies detected during the hands-on inspections could not have been observed from the ground. – TRR No. 2550, 2016

• Fall Protection Competent Person: OSHA 1926 Subpart M


. . . . .Difficult Access• 4% (~50) sign foundations require a

snooper or rope access – SPRAT Training


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OUTLINE

. . . . .Nationwide

“A few collapses of these structures are typically reported each year. In some cases, vehicles have collided with the fallen structures, resulting in serious injuries and fatalities.” -NCHRP Report 469, Fatigue Resistant Design of Cantilevered Signal, Sign, and Light Supports

• 36 states responded-half reported issues; 43 fatigue failure cases documented mid-90’s

University of Alabama report says approximately 20 cantilever structures fail each year primarily due to wind induced fatigue vibrations.

Statewide

Of the 1351 signs currently in the DOTD inventory:

• No reported failures and no safety incidences

• 22 Overhead Sign Structures have been removed from service

• 288 have “required maintenance” flags

• 130 have cracked welds (10%)

Failure – NOT an option

. . . . .Butterfly mounted to I-20 median


. . . . .Butterfly mounted to I-20 median


. . . . .Loose/Missing anchor bolt hardware

• “Snug-tight” is defined as nuts tightened to a torque between 20 and 30 percent of the verification torque


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TWIN SPAN

• 5 Aluminum Span Box Truss Signs

• 6252-093: 6 fractured welds; 9 cracked welds; 4/9 cracked welds extend up to 2.5” into chords


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I-10 CASE STUDY

0236-001,002; 6252-093, 6252-106


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TWIN SPAN

• 6252-062 - Initial inspection: 2 fractured welds, 2 cracked welds

• 6252-062 - Interim inspection (12 month): 3 fractured welds, 7 cracked welds; 2/7 cracks extend into chord


. . . . .TWIN SPAN

• Span Signs were removed within days of inspection


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Corroded columns


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Standoff distance

Corroded anchor bolts


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Impact damage


. . . . .Guardrail damage


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Preventative maintenance reduces life cycle costs

• Inspectors snug tighten loose nuts verification torque

• Spray localized areas of paint failure recoat to standard

• General maintenance recommendations:

• Analyze standoff distance and reduce if necessary

• Dig out and shore up a buried foundation

• Remove/repair grout pads

• Install caps

• Install missing clips

• Repair reflectivity


. . . . .Conclusion

Introduction - Ancillary Program

LADOTD Overhead Sign Truss Inspection Program

Raised awareness of local failure modes

. . . . .Technical References

• FHWA: Guidelines for the Installation, Inspection, Maintenance and Repair of Structural Supports for Highway Signs, Luminaires, and Traffic Signals

• AASHTO: Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals

• AASHTO: LRFD Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals

• NCHRP Report 469: Fatigue-Resistant Design of Cantilevered Signal, Sign, and Light Supports

• NCHRP Report 494: Structural Supports for Highway Signs, Luminaires and Traffic Signals

• TRR 2550: Field Study of Ohio’s Structural Support Inspection Program for Overhead Signs, Traffic Signals, and High-Mast Lights

• VIRGINIA DOT: Traffic Ancillary Structures Inventory & Inspection Manual

• NEW YORK DOT: Overhead Sign Structure Inventory & Inspection Manual

• OHIO DOT: Evaluation of Overhead Support Inspection Program

• OREGON DOT: Bridge Inspection Program Manual, Chapter 21

• LADOTD: Upcoming

. . . . .Professional Reference

Moffatt & Nichol – Engineering design firm with over 50 talented, experienced, and certified transportation inspectors.

Chace Hulon, PE

Project Manager

Bridge Engineer-Diver/Climber

[email protected]

407.414.8752

MISSION: To be the best, not the biggest. We view our growth as the byproduct of providing valued services to our clients.

mailto:[email protected]

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Documents

· ... Standard Specifications for Structural Supports for Highway ... Structural Supports for Highway Signs, ... Evaluation of Overhead Support Inspection Program