PowerPoint PresentationOctober 23, 2019
Dave Kennicutt PE, Senior Project Manager Delta Engineers, Architects, & Land Surveyors DPC
William Horne PE, President NDT Corporation
Outline
The Bridge
The Bridge
Red Flag
• Section loss in pile bent near water line
• 100% loss in begin right flange of Pile #5 (furthest upstream)
• 78% average flange loss in Pile #5 • Flange loss ranging from 61 – 73% for
remaining piles
Pile #5
Pile #5
Initial Recommendation
• Keep bridge open and load post for 5 tons based on:
• Better condition than similar bridge recently analyzed
• Lack of visible deformation, e.g. no buckling
• No PIA designation on flag
Investigation and Analysis
• Field measured extent of deterioration • Analysis results
• Can maintain 5 ton posting • Must shift traffic to downstream side
of bridge • Cannot sustain heavy traffic barrier • Permanent repair requires excavation
around piles • Confirmation of pile embedment
Outline
• Velocity (compressional & shear waves)
Thickness Delamination Strength (Vertical)
Normal Compressional and Shear Wave Velocity Values
Lower Compressional Velocity and Lower or Loss of Shear Velocity Values
Impact
Sensors
Full Thickness Pipe Resonance No Resonance Coating Thickness
Resonance
Impact
Sensors
Faster Velocity = Stronger Material
Granite is stronger than shale Glacial till is stronger than clay Compacted sand is stronger (soil)
Outline
24
Seismic Refraction Survey Black powder shotgun shells & 100-400 ft. arrays Velocity can be used to measure rock strength
Direct Wave
Refracted Wave
Energy Source
500
1000
1500
2000
2500
3000
4000 4025 4050 4075 4100 4125 4150 4175 4200 4225 4250 4275 4300 4325 4350 4375 4400 4425 4450 4475 4500 4525 4550 4575 4600 4625 4650 4675 4700 4725 4750 4775 4800 4825 4850 4875 4900 4925 4950 4975 5000
Ohm-meter
10,000-14,000 ft/sec bedrock
Pile Testing
End of Pile
Pile Testing
Outline
Foundation/Pile Alternate Methods
Determining Fill Characteristics
Arch
CROSS-SECTION
Outline
Permanent Repair
• Strengthen cross bracing • Insert angle struts to reduce
unbraced length of piles • Restore pre-flag load capacity (18
tons)
Summary
• Seismic refraction survey determined bedrock depth and overburden competency of deposits
• Impact echo testing determined the pile embedment
• Riverbed excavation was determined to be feasible
• Repairs resulted in no reduction in load posting
• Bridge remains open and the service life was extended
Statement of Learning Question
What test method can determine the concrete compressive strength?
A. Ground penetrating radar B. Infrared thermography C. Pulse velocity D.Half cell corrosion potential
What test method can determine the concrete compressive strength?
Pulse velocity
What can be used to measure the strength of rock
A. Unconfined Compressive strength B. Rock Quality Determination (RQD) C. Measured energy wave velocities D.All of the above
Statement of Learning Question
What can be used to measure the strength of rock
All of the Above
Statement of Learning Question
What nondestructive method determines the lengths of piles?
A. Impact Echo B. Ground penetrating radar C. Schmidt Hammer D.Half Cell potential
Statement of Learning Question
Impact echo
How to calculate the length of a pile?
A. Thickness of the pile times 3.14285714 B. Visible height of the pile times 2
subtract 10% and add 32 C. Velocity of the energy wave times the
measured travel time D.(Velocity of the energy wave times the
measured travel time)/2
How to calculate the length of a pile?
(Velocity of the energy wave times the measured travel time) / 2
Statement of Learning Question
Determining H-pile Lengths using Non-Destructive Test Methods October 23, 2019
Tioga County BIN 2218720 Harnick Road over Apalachin Creek. Gary Hammond PE, Commissioner of Public Works Tioga CountyDave Kennicutt PE, Senior Project Manager Delta Engineers, Architects, & Land Surveyors DPCWilliam Horne PE, President NDT Corporation
Outline
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