Superload Move

April 06, 2013

Prasad Nallapaneni & Jonathan Mallard

Structure and Bridge, VDOT

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Superload - Route

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Superload- Details

Total Distance : Approximately 96 Miles

Number of Structures: 62 (61 VDOT)Bridges: 25

Culverts: 37

VDOT Structures:Analyzed in-house: 47

Third Party Analysis: 16

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Superload - Detials

Analysis Method: In house: LFR/LRFR –

»VIRTIS if available»Compared Simple span moments

with HS20 ratings

Third Party: LRFR -16 Bridges

Verified hand calculations

/ LFR analysis

Structures Jumped: 5 (five)

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Superload - Permit

6

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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Superload

Attempt 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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Superload

Bridge Fed ID: 24505

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Superload

BrR ModelHand Clacs % Diff Reason

Dead Load Moment (K ft) 1550 1519 2.04%

Model has slightly higher Superimposed loads

Capacity (K Ft) 6271 6221 0.80% Round of error

Rating 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: 24505

Wheel Configuration: Straight

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Superload

Bridge Fed ID: 25334

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Superload

BrR ModelHand Clacs % Diff Reason

Dead Load Moment (K ft) 5701 5691 0.18%

Round OffCapacity (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: 25334

Wheel Configuration: Straight

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Superload

Bridge 24231

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Superload

BrR ModelHand 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: 24231

Wheel Configuration: Straight

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Superload

Difficulties 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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Superload

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

 

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

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Field Operations

Field 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 Operations

Structure 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 Operations

Structure 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 Operations

Structure 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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