· ... Standard Specifications for Structural Supports for Highway ... Structural Supports for...
Transcript of · ... Standard Specifications for Structural Supports for Highway ... Structural Supports for...
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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
Ancillary Program - Overview
. . . . .Overhead Sign Structures (OSS): structural elements designed to carry signs over the roadway and are attached to a designed foundation.
Ancillary Program - Overview
. . . . .Overhead Sign Structures (OSS): structural elements designed to carry signs over the roadway and are attached to a designed foundation.
Ancillary Program - Overview
. . . . .Overhead Sign Structures (OSS): structural elements designed to carry signs over the roadway and are attached to a designed foundation.
Ancillary Program - Overview
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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
Ancillary Program - Overview
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Inspection Types:
• Initial, Routine, In-Depth, Interim, Damage
Frequencies:
Ancillary Program - Overview
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
Ancillary Program - Overview
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NDT Equipment
• Ultrasonic Flaw Detector
• Dye Penetrant / Mag Particle
Ancillary Program - Overview
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Traffic Control
• Portable signs, cones, 360˚ high intensity light and strobes, MUTCD
Ancillary Program - Overview
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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
Ancillary Program - Overview
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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1. Ancillary Program – Overview
2. LADOTD – We’re on the map
3. Failure – NOT an option
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
LADOTD – We’re on the map
. . . . .Difficult Access• 4% (~50) sign foundations require a
snooper or rope access – SPRAT Training
LADOTD – We’re on the map
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1. Ancillary Program – Overview
2. LADOTD – We’re on the map
3. Failure – NOT an option
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
Failure – NOT an option
. . . . .Butterfly mounted to I-20 median
Failure – NOT an option
. . . . .Loose/Missing anchor bolt hardware
• “Snug-tight” is defined as nuts tightened to a torque between 20 and 30 percent of the verification torque
Failure – NOT an option
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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
Failure – NOT an option
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I-10 CASE STUDY
0236-001,002; 6252-093, 6252-106
Failure – NOT an option
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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
Failure – NOT an option
. . . . .TWIN SPAN
• Span Signs were removed within days of inspection
Failure – NOT an option
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Corroded columns
Failure – NOT an option
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Standoff distance
Corroded anchor bolts
Failure – NOT an option
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Impact damage
Failure – NOT an option
. . . . .Guardrail damage
Failure – NOT an option
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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
Failure – NOT an option
. . . . .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
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.
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