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SPR 4009 Box Beam Study 2/14/2019
1
ADJACENT PRESTRESSED,
PRECAST BOX BEAM BRIDGES
RYAN WHELCHEL, Purdue University
RYAN MOLLEY, KPFF
LUIS FELIPE URREGO, Universidad de los Andes
ROBERT FROSCH, Purdue University
CHRISTOPHER WILLIAMS, Purdue University
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2
• Box Girders
• Shear Keys
• Tie Rods
• Wearing Surface
AN ADJACENT BOX BEAM BRIDGE
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1
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SPR 4009 Box Beam Study 2/14/2019
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PROJECT MOTIVATION
• History of poor durability and performance
• Economical and simple to build
• Over 43,000 in US and 4,000 in Indiana
3
RESEARCH PLAN
• Acquire decommissioned bridge girders
• Research and acquire NDT equipment
• Conduct non‐destructive evaluation
• Perform structural tests
• Load test an existing bridge to determine load
distribution of a non‐composite deck on a
bridge without shear keys
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SPR 4009 Box Beam Study 2/14/2019
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SPECIMEN ACQUISITION
• Determine those bridges that will be replaced
• Inspect bridges to determine specimen quality
• Contact County, Engineer, or Contractor to
coordinate girder salvage
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COMMON DETERIORATION
• Longitudinal Cracking • Exposed or Broken Strand
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5
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SPR 4009 Box Beam Study 2/14/2019
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BOX BEAM SPECIMENS
Wells Co. Bridge 79
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BOX BEAM SPECIMENS
Newton Co. Bridge K5
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7
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SPR 4009 Box Beam Study 2/14/2019
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BOX BEAM SPECIMENS
Elkhart Co. Bridge 102
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NONDESTRUCTIVE TESTING
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SPR 4009 Box Beam Study 2/14/2019
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NON‐DESTRUCTIVE EVALUATION (NDE)
Ground Penetrating Radar (GPR)
Connectionless Electrical Pulse Response Analysis
(CEPRA)
Half‐cell potential measurement
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PRELIMINARY NDE RESULTS
Specimen 409‐1‐ESSpan: 50’Depth: 29”Width: 36”
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11
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SPR 4009 Box Beam Study 2/14/2019
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PRELIMINARY NDE RESULTS
Connectionless Electrical Pulse Response Analysis
Low Moderate High
0
5.1
10.3
15.4
20.6
25.7
30.9
36.0
0 5 10 15 20 25 30 35 40 45 50
Tra
nsve
rse
Loca
tion
(in.)
Longitudinal Location (ft)
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PRELIMINARY NDE RESULTS
Half‐cell potential measurement
0
5.1
10.3
15.4
20.6
25.7
30.9
36.0
0 5 10 15 20 25 30 35 40 45 50
Tra
nsve
rse
Loca
tion
(in.)
Longitudinal Location (ft)
Low Moderate High
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SPR 4009 Box Beam Study 2/14/2019
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STRUCTURALTESTING
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BEAM TEST
Load Points
Roller Bearing (TYP)
Reaction Block (TYP)
String Potentiometers (two at midspan)
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SPR 4009 Box Beam Study 2/14/2019
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BEAM TEST
Specimen 409‐1‐ES
• Three exposed strands at L/8 from support
Specimen 409‐2‐UD
• No damage
~ 12 in.
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BEAM TEST
0
10
20
30
40
50
60
0 5 10 15 20 25
App
lied
For
ce (
kip)
Midspan Deflection (in.)
42 kip - Undamaged Capacity
34 kip - Damaged Capacity
52 kip - Test
47 kip - Theory
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17
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SPR 4009 Box Beam Study 2/14/2019
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BEAM TEST
0
10
20
30
40
50
60
0 5 10 15 20 25
App
lied
For
ce (
kip)
Midspan Deflection (in.)
42 kip - Undamaged Capacity
47 kip - Theory
50 kip - Test
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20
BEAM TEST
0
10
20
30
40
50
60
0 5 10 15 20 25
App
lied
For
ce (
kip)
Midspan Deflection (in.)
52 kip - Test
47 kip - Theory
50 kip - Test
20
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SPR 4009 Box Beam Study 2/14/2019
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FIELD TESTING
TIPPECANOE COUNTY BRIDGE 115
• Built: 1957
• Rehabilitated: 1993
• Span: 40 ft
• Beam Depth: 21 in.
• Beam Width: 45 in.
• 7 Beams
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21
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SPR 4009 Box Beam Study 2/14/2019
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INTRODUCTION
INSTRUMENTATION
10’ 10’ 10’ 10’
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LOADING
Dump Truck
• Weight: ~ 58,000 lb
• 30% to front axle
• 70% to tandem axle
• Wheelbase: 16’ – 4”
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SPR 4009 Box Beam Study 2/14/2019
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� �
T E S T 1T E S T 2T E S T 3T E S T 4
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Bridge Deck Modifications
• Milling
• Shear Key Cutting
• Surface Preparation
• Bridge Deck Cast
FIELD TESTING
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25
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SPR 4009 Box Beam Study 2/14/2019
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1 2 3 4 5 6 7
10' 10' 10' 10'
East West
‐0.2
‐0.18
‐0.16
‐0.14
‐0.12
‐0.1
‐0.08
‐0.06
‐0.04
‐0.02
0
1 2 3 4 5 6 7
Midspan
Deflection (in.)
Beam Number
LT1 ‐ Original Condition
LT2 ‐ Asphalt Removed
LT3 ‐ Shear Keys Disabled
LT4 ‐ Concrete Deck Placed
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1 2 3 4 5 6 7
10' 10' 10' 10'
East West
‐0.2
‐0.18
‐0.16
‐0.14
‐0.12
‐0.1
‐0.08
‐0.06
‐0.04
‐0.02
0
1 2 3 4 5 6 7
Midspan
Deflection (in.)
Beam Number
Original Condition
Concrete Deck Placed
35% reduction in deflection
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SPR 4009 Box Beam Study 2/14/2019
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LOAD DISTRIBUTION
• The proportion of load carried by a given
beam was calculated as follows
𝐷𝐹∆∑∆
29
10' 10' 10' 10'
East West
1 2 3 4 5 6 7
0%
5%
10%
15%
20%
25%
30%
1 2 3 4 5 6 7
Load
Dis
trib
utio
n
Beam Number
LT01 LT0430
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SPR 4009 Box Beam Study 2/14/2019
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10' 10' 10' 10'
East West
0%
5%
10%
15%
20%
25%
30%
1 2 3 4 5 6 7
Load
Dis
trib
utio
n
Beam Number
LT01 LT04
1 2 3 4 5 6 7
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LOAD DISTRIBUTION SUMMARY
Load Test Interior Exterior
LT01 22% 23%
LT04 22% 25%
Design Distribution Factors
Interior Exterior
21% 24%
AASHTO LRFD 2017
Load Fraction (truck)
32%
AASHTO Standard Specification 2002
Experimental Distribution Factors
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SPR 4009 Box Beam Study 2/14/2019
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FIELD TEST CONCLUSIONS
• Concrete deck restored load distribution to a
code level
• Durability and stiffness were added to the
system
• Composite action between the deck and the
beams was achieved
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IMPLICATIONS TO BEST PRACTICE
• Recommend all new construction use
concrete decks
• Potential new design of adjacent box
beam bridges without shear keys
Concrete Deck Sealant
Standard Box Beam Shape
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SPR 4009 Box Beam Study 2/14/2019
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PROJECT BENEFITS
• Improved inspection capability for bridge
inspectors
• Increase in bridge load rating accuracy
• Development of next generation box beams
35
ACKNOWLEDGMENTS
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SPR 4009 Box Beam Study 2/14/2019
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THANK YOU
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