load rating reinforced concrete box culverts - stgec. lawson - load... · research synthesis load...
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RESEARCH SYNTHESIS
LOAD RATING REINFORCED CONCRETE BOX CULVERTS
William D. Lawson, P.E., Ph.D.
Department of Civil and Environmental Engineering Texas Tech University
STGEC 2013 44th Southeast Transportation Geotechnical Engineering Conference Crowne Plaza Hotel: Baton Rouge, LA Wednesday, December 4, 2013
FIRST PROJECT: TXDOT 0-5849 EVALUATING EXISTING CULVERTS FOR LOAD CAPACITY ALLOWING FOR SOIL STRUCTURE INTERACTION 2007-2009
RESEARCH SYNTHESIS LOAD RATING REINFORECED CONCRETE BOXED CULVERTS
Load Rating Culverts Slide 2 STGEC: 4 DEC 2013
The Research Problem
• When rights-of-way crossing existing culverts have to be raised and/or widened, the culverts have to be reanalyzed.
• Current analysis methods (direct stiffness) and AASHTO loading protocols often result in such culverts being judged deficient.
• The direct-stiffness method is too conservative in that it does not account for (beneficial) soil-structure interaction effects.
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Modification
• New Problem: TxDOT’s “current” rating procedure was not clear, repeatable
• Solution: articulate a clear, repeatable procedure in the Culvert Rating Guide
• Quality Assurance: conduct a series of quality checks to demonstrate that the Culvert Rating Guide is clear, repeatable, and valid for TxDOT culverts
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Culvert load rating is about going from here…
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to here…
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I) (1 LA
DA C RF
2
1
Load
Rat
ing
Flo
w C
har
t C
ulv
ert
Ra
tin
g G
uid
e
Load Rating Culverts TxDOT 5-5849-03 10
Load Rating Culverts STGEC: 4 DEC 2013 11
Load Rating Culverts STGEC: 4 DEC 2013 12
so you can check here.
Field Instrumentation and Load Testing
• Live Load and Operating Rating Case Studies – Case 1: Shallowater
• 2’ Fill
• 4’ Fill
– Case 2: Plainview
– Case 3: Tulia
• Dead Load Concerns
• Conclusions
• Recommendations
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Culvert Selection: Shallowater, Plainview, Tulia
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Case 1: Shallowater Instrumentation Plan
ETEC ETEM ETIC1 ETIC2 ETIM ETIC3
EWTECITEC ITEM ITIC1 ITIC2 ITIM ITIC3
IBEC IBEM IBIC1 IBIC2 IBIM IBIC3 IBIC4
IWTEC IWTIC1 IWTIC2 IWTIC3 IWTIC4
IWBEC IWBIC1 IWBIC2 IWBIC3 IWBIC4
median drainage
4'-0"
4'-0"
8" 8"
7 12
"
LVDT TES
LVDT BES
LVDT TIS
LVDT BIS
4'-0" 1'-0" 1'-0" 4'-0" 1'-0" 1'-0" 4'-0"
IWEM
MA
TCH
LIN
E
4'-0"
IWIM1 IWIM2 IWIM3 IWIM4
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Lay Out the Gage Line
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First Pass: One Truck Straddles Gage Line
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Third Pass: Two Trucks Straddle Gage Line
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Data Recording
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-10.000
-8.000
-6.000
-4.000
-2.000
0.000
2.000
4.000
6.000
8.000
CULV-5 MAX
CULV-5 MIN
RISA-2D TEXT MAX
RISA-2D TEXT MIN
RISA-2D STRUC MAX
RISA-2D STRUC MIN
RISA-2D LEFE CRG MAX
RISA-2D LEFE CRG MIN
RISA-2D LEFE Bowles MAX
RISA-2D LEFE Bowles MIN
RISA-2D LEFE SPT/TCP MAX
RISA-2D LEFE SPT/TCP MIN
RISA-2D LEFE DCP MAX
RISA-2D LEFE DCP MIN
RISA-2D LEFE PMT MAX
RISA-2D LEFE PMT MIN
RISA-2D LEFE FWD MAX
RISA-2D LEFE FWD MIN
ACTUAL MAX
ACTUAL MIN
Case 1: Shallowater: 2’ Fill Live Load Moment Predicted and Measured
Validation of the TxDOT Culvert Rating Guide
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0.01 0.1 1 10 100 1000
Level 3 DOF=4.0ft
Level 3 DOF=3.5ft
Level 3 DOF=2.0ft
Level 3 DOF=1.5ft
Level 1 DOF=4.0ft
Level 1 DOF=3.5ft
Level 1 DOF=2.0ft
Level 1 DOF=1.5ft
predicted / measured
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SECOND PROJECT: TXDOT 5-5849-01 SOFTWARE DEVELOPMENT TO IMPLEMENT THE TXDOT CULVERT RATING GUIDE 2012-2013
RESEARCH SYNTHESIS LOAD RATING REINFORECED CONCRETE BOXED CULVERTS
Load Rating Culverts Slide 23 STGEC: 4 DEC 2013
CULVLR 1.0.2
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CULVLR Input
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CULVLR Critical Section Details
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CULVLR Capacity Calculations
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CULVLR Demand Modeling
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CULVLR Load Rating Calculations
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THIRD PROJECT: TXDOT 5-5849-03 LOAD RATING TXDOT CULVERT DESIGN STANDARDS 2012-2013
RESEARCH SYNTHESIS LOAD RATING REINFORECED CONCRETE BOXED CULVERTS
Load Rating Culverts Slide 31 STGEC: 4 DEC 2013
Completed Load Rating Work • Digitization of TxDOT’s Design Standards for CULVLR (1855 Designs)
• Level 1/AASHTO Policy Load Ratings of Designs (~60,000 Load Ratings)
– CULV5 (60/30pcf Equivalent Fluid Weights)
– Range of Depths of Fill • Level 3/AASHTO Policy Load Ratings of Designs (~2,500 Load Ratings)
– RISA-3D (High, Medium and Low soil stiffnesses)
– Critical Depth of Fill from Level 1/AASHTO Load Ratings • Level 1/TxDOT Practice Load Ratings of Designs (~60,000 Load Ratings)
– CULV5 (40/20pcf equivalent fluid weights; ignore bottom slab)
– Range of Depths of Fill
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5-5849-03 Load Rating Standard Designs
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Load Posting Chart 5-5849-03 Culvert Rating Guide
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5-5849-03 Volume 1 All Analyses – Level 1/AASHTO
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145, 8% 18, 1%
196, 10%
694, 37%
587, 32%
215, 12%
OR < 3
IR<3, OR>3
IR>3, OR<10
IR<20, 10<OR<20
IR<20, OR>20
IR>20, OR>20
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Load Rating Culverts STGEC: 4 DEC 2013 37
5-5849-03 Volume 2 All Analyses – Level 3/AASHTO
0
215 215 215
0
587 587 587
215
261 155
15
587
574
485
168
694
208
166
302
196
0
8
55
18
0
0
4
145 10
21
96
0 0
0
195
0 0
218 218
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Level 1 AASHTO Level 3 High Level 3 Medium Level 3 Low
Pe
rce
nta
ge o
f To
tal L
oad
Rat
ings
Case D - NG
Case C - NG
OR < 3
IR<3, OR>3
IR>3, OR<10
IR<20, 10<OR<20
IR<20, OR>20
IR>20, OR>20
Case B - OK
Case A - OK
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Culvert Load Rating Lessons Learned 1. Culvert load rating is highly complex.
2. Production load rating tools achieve efficiency in effort at the expense of analytical simplification, the result being excess conservatism (non-uniform).
3. Increased analytical sophistication reduces excess conservatism.
4. TxDOT’s culvert designs are generally good relative to the policy for which they were designed; that is, TxDOT culvert design standards have not been heavily over-designed.
5. Load rating applies to a physical culvert structure where all key parameters are identified.
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nu
mb
er
of
con
stru
cte
d c
ulv
ert
s
Construction year
Culverts by Construction Year
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Much remains to be done…
TxDOT PMC
• Bernie Carrasco, PE (PD)
• Keith Ramsey, PE
• Farren Basse, PE
• Jon Kilgore, PE
• Roger Lopez, PE
• Mark McClelland, PE
• Mark Steves, PE
• Gregg Freeby, PE
TechMRT
• Timothy Wood, MS
• Chuck Newhouse, PhD, PE
• Priyantha Jayawickrama, PhD
• Stephen Morse, PhD
• Suranga Gunerathne
• Rozbeh Moghaddam
• William Lawson, PE, PhD (RS)
TxDOT Lubbock
• Ron Baker, PE
• Ted Moore, PE
• Benito Sanchez, PE
• Lubbock NW, Plainview, & Tulia Maintenance Sections
TxDOT 0-5849 Project Team
THANK YOU!!!