Superload MoveApril 06, 2013Prasad Nallapaneni & Jonathan MallardStructure and Bridge, VDOT

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Superload - Route

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Superload- DetailsTotal Distance :

Approximately 96 Miles Number of Structures: 62 (61 VDOT)

Bridges: 25Culverts: 37

VDOT Structures:Analyzed in-house: 47Third Party Analysis: 16

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Superload - DetialsAnalysis Method:

In house: LFR/LRFR – »VIRTIS if available»Compared Simple span moments with HS20 ratings

Third Party: LRFR -16 BridgesVerified hand calculations/ LFR analysis

Structures Jumped: 5 (five)

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Superload - Permit

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Superload - Permit

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Superload - Jump

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Superload - Restrictions

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Superload - Crabs

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Superload

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Superload

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SuperloadAttempt Made:

• Run few bridges in 6.5 with Non Standard Gage Vehicle

• Compare with calculations received from Third Party and in-house STAAD runs

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SuperloadBridge Fed ID: 24505

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Superload

BrR Model Hand Clacs % Diff Reason

Dead Load Moment (K ft) 1550 1519 2.04% Model has slightly higher

Superimposed loadsCapacity (K Ft) 6271 6221 0.80% Round of errorRating Factor 2.01 2.09 -4.22%  

Live Load (K ft) 2355 2246 4.83%

May be round off error in Distribution Factor. No detail output in BrR for

Live Load.

Bridge Fed ID: 24505Wheel Configuration: Straight

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SuperloadBridge Fed ID: 25334

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Superload

BrR Model Hand Clacs % Diff Reason

Dead Load Moment (K ft) 5701 5691 0.18% Round Off

Capacity (K Ft) 15475 15463 0.08% Round OffRating Factor 1.11 1.19 -6.48%  

Live Load (K ft) 8805 8233 6.95%

May be round off error in Distribution Factor. No detail output in BrR for

Live Load.

Bridge Fed ID: 25334Wheel Configuration: Straight

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SuperloadBridge 24231

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Superload

BrR Model Hand Clacs % Diff Reason

Dead Load Moment (K ft) 320 320 0.0%

Capacity (K Ft) 1828 1828 0.08%Rating Factor 2.07 2.19 -5.6%  

Live Load (K ft) 729 688 5.93%

May be round off error in Distribution Factor. No detail output in BrR for

Live Load.

Bridge Fed ID: 24231Wheel Configuration: Straight

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SuperloadDifficulties Faced

• Installation issues with 64 vs. 32 bit• Long time run process• Memory issues• Run only from bridge explorer • Not able to get a detailed LL output.

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Superload

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Superloadhttp://www.youtube.com/watch?v=Dmacnt5GaHw http://www.youtube.com/watch?v=v8_3uyecXSc

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Field OperationsField Surveys• LIDAR survey was taken before and after on 5 long

span structures.• Calculated LL deflections from vehicle were up to 6”• Survey showed before and after elevations of the

bridge deck surface and the bottoms of the girders were within the tolerance of the method used.

• Any post move deflection was undetectable from a survey perspective.

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Field OperationsStructure 10720, Lee County• Originally designated to be ‘jumped’• Field review of route raised concerns about limited

hospital access for an extended period.• Detour length = 50 miles.• Hauler’s consultants recommended removing a 20 kip

counterweight from each of the tractors.• Tractors effectiveness was limited due to traction

loss.

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Field OperationsStructure 24362, Norton• Rated by private consultant. Substructure controlled

at pier due to uneven span arrangement• Travel restrictions were issued. • During transport, hydraulic line broke while crossing

the structure. Lead tractor was over critical pier.• After line replacement, vehicle initiated movement

from rear tractor, which was not on bridge.

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Field OperationsStructure 22454, Norton• Simple Span Plate Girder with partial depth welded

diaphragms• First diaphragm on girder 4 cracked at the base.• Retrofitted by drilling, arrested by next inspection

cycle.

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