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3-D Finite Element Analysis and Load Rating of I-10 Calcasieu River
Bridge, Lake Charles
SDR Engineering Consultants, Inc. 2260 Wednesday Street, Suite 500
Tallahassee, FL 32308 Tel: 850-222-2737 Fax: 850-386-9197
Approach Span Load Rating
• Superstructure
• Bent cap
Main/Deck Truss Load Rating
• Tension/compression member
• Gusset plate
• Floor beam
• Stringers
TRUSS SPAN PROFILE
Three main truss spans, total length 840 ft
Four deck truss spans, 180 ft each
Members are mainly built-up box section
FLOOR BEAM SWAY FRAME
MAIN TRUSS CROSS-SECTION
Stringers are rolled I-section
Floor beams are built-up I-sections
Floor beams are strengthened with cover plates
APPROACH SPANS PROFILE
West Approach
Steel girder spans: Span 1 to 45
Fracture critical spans: Span 46 to 52
APPROACH SPANS PROFILE
East Approach
Fracture critical spans: Span 60 to 66
Steel girder spans: Span 67 to 97
APPROACHES CROSS-SECTION
INCORPORATE INSPECTION RESULTS
Verification: • Element size and geometry • Number of bolts/rivets • Section losses • Missing information
Design Plan Survey
ANALYSIS SOFTWARE
Element Computer Software
Truss member LUSAS, Excel
Truss gusset plate LUSAS, Excel
Truss floor beam LUSAS, Excel
Truss stringer Virtis
Approach span beam Virtis, Excel
Approach span pier cap RC-Pier, Excel
MAIN/DECK TRUSS LOAD RATING
LUSAS MODELING
FEA Model
LUSAS MODELING
Close-up View
LUSAS MODELING
Close-up View
HINGES AT END OF DROP SPANS
LUSAS MODEL VS. DESIGN PLAN
0
250
500
750
1000
1250
1500
1750
2000
Mem
ber
Fo
rce
(kip
s)
Top Chord Dead Load Comparison
LUSAS
Plan
LUSAS MODEL VS. DESIGN PLAN
0
250
500
750
1000
1250
1500
1750
2000
Me
mb
er
Forc
e (
kip
s)
Bottom Chord Dead Load Comparison
LUSAS
Plan
LOADING POSITIONS
C NORTH TRUSS L C SOUTH TRUSS L C BRIDGE L
12’
D
0.64 k/ft
6’
12’
2’ B
0.64 k/ft
6’
12’
A
0.64 k/ft
6’ 12’
2’ C
0.64 k/ft
6’
12’
2’ E
0.64 k/ft
6’
12’
F
0.64 k/ft
6’
12’
D
0.64 k/ft
6’
12’
2’ E
0.64 k/ft
6’
12’
F
0.64 k/ft
6’
12’
2’ C
0.64 k/ft
6’
LOAD COMBINATIONS
For Truss Members
Load Combination M.P.F
E 1.2
E+F 1.0
E+F+C 0.85
E+F+C+D 0.65
C NORTH TRUSS L C SOUTH TRUSS L C BRIDGE L
LOAD COMBINATIONS For Floor Beams
Lanes Loaded Load Combination MPF
1-Lane E, F, B, A 1.2
2-Lane B+A, B+C, B+D, A+C, A+D, E+F,
E+A, E+C, E+D, F+C, F+D, C+D
1.0
3-Lane B+A+C, B+A+D, E+F+C,
E+F+D, E+C+D, F+C+D
0.85
4-Lane B+A+C+D, E+F+C+D 0.65
E F A B C D
C NORTH TRUSS L C SOUTH TRUSS L C BRIDGE L
TRUCK LOAD
Step 1 Step 2 Step 3 Step 4 …….
……. Step41
LANE LOAD
0.64 k/ft
Step 1
0.64 k/ft
Step 2
0.64 k/ft
Step 3
0.64 k/ft
Step 4
0.64 k/ft
Step 10 ……. Step40
0.64 k/ft
Step 5
0.64 k/ft
Step 6
0.64 k/ft
Step 7
0.64 k/ft
Step 8
0.64 k/ft
Step 9
LOAD RATING OF TRUSS
• Tension/Compression Members
• Gusset Plates (Local and Global)
• Floor beams
• Stringers
Elements to be Rated:
Rating Equation:
LOAD RATING OF TENSION/COMPRESSION MEMBER
Tension Member Capacity
Yield on gross section
Fracture on net section Smaller of
Compression Members Capacity
Built-up I Sections:
Built-up Box Sections:
Flange local buckling
Web local buckling
Plate local buckling (include perforated plate)
Angle leg buckling
Global buckling considering modified slenderness ratio for built-up sections (AISC Section E6)
Load Rating of Compression Members
• The unbraced length, L, is determined as distance between centerline of connection of member end, as shown in the Figure below.
• K- factor for rotational and translational boundary condition. Use k=0.75 for bolted ends
LOAD RATING OF GUSSET PLATE (Local)
Resistance of Fasteners
Resistance of Gusset Plates
• Gusset Plates in Tension • Yield on the gross section • Fracture on the net section • Block shear rupture
• Gusset Plates in Compression
• Shear Resistance of Fasteners • Plate Bearing Resistance of Fasteners
30°
30° 30°
30°
LOAD RATING OF GUSSET PLATE (Local)
Tension on Whitmore Width
Block Shear
L1
L2
L3
Compression on unbraced length (Avg of L1,L2,L3)
Gross Section Shear Net Section Shear
B
A A
B
Max. Concurrent Forces
Max. Concurrent Forces
LOAD RATING OF GUSSET PLATE (Global)
SPECIAL CONSIDERATION ON GUSSET PLATE
• Add to the local capacity of gusset plate
Splice plate and lateral plate
Double gusset plate
• Add to both local and global capacity of gusset plate
• Consider only one shear plan for bolts
Chord member bearing on each other
• Force deducted by 50% according to design plan
A
A
B
B
C L
B - B A - A
Floor Beam Sections
LOAD RATING OF FLOOR BEAMS
LOAD RATING OF FLOOR BEAMS
Flexure Resistance (Section A-A and B-B):
• Compression Flange
• Tension Flange (A6.10.8.3)
• Local Buckling Resistance (A6.10.8.2.2)
• Lateral torsional Buckling Resistance (A6.10.8.2.3)
Smaller of
Shear Resistance:
• End Panel (A6.10.9.3.3)
• Interior Panel (A6.10.9.3.2)
• Cover plates are included in analysis
RATING SUMMARY FOR TRUSS MEMBERS
Loads Vehicles Rating Factor Controlling Case
Design
HL-93, Positive (Inv) 0.98 Strength I - Compression
HL-93, Positive (Opt) 1.27 Strength I - Compression
HL-93, Negative (Inv) 1.03 Strength I - Compression
HL-93, Negative (Opt) 1.34 Strength I - Compression
Legal
LA Type 3 2.02 Strength I - Compression
LA Type 3-S2 1.22 Strength I - Compression
AASHTO Type 3-3 1.66 Strength I - Compression
LA Type 6 1.42 Strength I - Compression
LA Type 8 1.23 Strength I - Compression
Lane Type Pos. 1.87 Strength I - Compression
Lane Type Neg. 1.53 Strength I - Compression
SHV NRL 1.17 Strength I - Compression
Permit
OFRD #1 0.86 Strength II - Compression
OFRD #2 0.77 Strength II - Compression
OFRD #3 0.78 Strength II - Compression
RATING SUMMARY FOR GUSSET PLATES
Loads Vehicles Rating Factor Controlling Case
Design
HL-93, Positive (Inv) 0.87 Strength I - Global
HL-93, Positive (Opt) 1.13 Strength I - Global
HL-93, Negative (Inv) 0.71 Strength I - Global
HL-93, Negative (Opt) 0.92 Strength I - Global
Legal
LA Type 3 2.50 Strength I - Global
LA Type 3-S2 1.56 Strength I - Global
AASHTO Type 3-3 1.56 Strength I - Global
LA Type 6 1.47 Strength I - Global
LA Type 8 1.33 Strength I - Global
Lane Type Pos. 1.52 Strength I - Global
Lane Type Neg. 1.05 Strength I - Global
SHV NRL 1.23 Service II - Global
Permit
OFRD #1 0.86 Strength II - Global
OFRD #2 0.85 Strength II - Global
OFRD #3 0.70 Strength II - Global
RATING SUMMARY FOR FLOOR BEAMS
Loads Vehicles Rating Factor Controlling Case
Design
HL-93, Positive (Inv) 1.08 Strength I - Flexural
HL-93, Positive (Opt) 1.40 Strength I - Flexural
HL-93, Negative (Inv) 1.26 Strength I - Flexural
HL-93, Negative (Opt) 1.63 Strength I - Flexural
Legal
LA Type 3 2.05 Strength I - Flexural
LA Type 3-S2 1.64 Strength I - Flexural
AASHTO Type 3-3 1.95 Strength I - Flexural
LA Type 6 1.64 Strength I - Flexural
LA Type 8 1.41 Strength I - Flexural
Lane Type Pos. 2.20 Strength I - Flexural
Lane Type Neg. 2.25 Strength I - Flexural
SHV NRL 1.32 Service II - Flexural
Permit
OFRD #1 0.99 Strength II - Flexural
OFRD #2 0.88 Strength II - Flexural
OFRD #3 0.97 Strength II - Flexural
Loads Vehicles Rating Factor Controlling Case
Design HL-93, Positive (Inv) 0.84 Strength I - Flexural
HL-93, Negative (Inv) 1.09 Strength I - Flexural
Legal
LA Type 3 1.55 Service II - Flexural
LA Type 3-S2 1.24 Service II - Flexural
AASHTO Type 3-3 1.35 Strength I - Flexural
LA Type 6 0.95 Strength I - Flexural
LA Type 8 0.89 Strength I - Flexural
SHV NRL 1.08 Service II - Flexural
Permit
OFRD #1 0.72 Strength II - Flexural
OFRD #2 0.88 Strength II - Flexural
OFRD #3 0.74 Strength II - Flexural
RATING SUMMARY FOR STRINGERS
APPROACH SPAN LOAD RATING
LOAD RATING OF APPROACH SPAN
• 5 unique steel girder spans
• 2 unique fracture critical spans
• Rated using Virtis and Excel
Superstructure
Bent Cap
• 5 unique models
• Rated using RC-Pier and Excel
Loads Vehicles Rating Factor Controlling Case
Design HL-93, Positive (Inv) 0.80 Strength I - Flexural
HL-93, Negative (Inv) 1.04 Strength I - Flexural
Legal
LA Type 3 1.27 Strength I - Flexural
LA Type 3-S2 1.01 Strength I - Flexural
AASHTO Type 3-3 1.49 Strength I - Flexural
LA Type 6 1.19 Strength I - Flexural
LA Type 8 1.11 Strength I - Flexural
SHV NRL 0.95 Service II - Flexural
Permit
OFRD #1 0.80 Strength II - Flexural
OFRD #2 0.74 Strength II - Flexural
OFRD #3 0.78 Strength II - Flexural
RATING SUMMARY FOR APPROACH SPAN SUPERSTRUCTURE
Loads Vehicles Rating Factor Controlling Case
Design HL-93, Positive (Inv) 1.04 Strength I - Shear
HL-93, Negative (Inv) 1.35 Strength I - Shear
Legal
LA Type 3 2.66 Strength I - Shear
LA Type 3-S2 1.52 Strength I - Shear
AASHTO Type 3-3 1.58 Strength I - Shear
LA Type 6 1.48 Strength I - Shear
LA Type 8 1.31 Strength I - Shear
SHV NRL 1.58 Strength I - Shear
Permit
OFRD #1 1.05 Strength II - Shear
OFRD #2 1.03 Strength II - Shear
OFRD #3 0.84 Strength II - Shear
RATING SUMMARY FOR APPROACH SPAN BENT CAP
Thank You
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