carroll harris presentation
DESCRIPTION
Carroll Harris PresentationTRANSCRIPT
Evaluation of the Sandwich Plate System in Bridge Decks Using a Plate Approach
Devin Harris – Michigan TechChris Carroll – Virginia Tech
A Comparison BetweenANSYS and GT STRUDL Models
Project Overview
POLYURETHANE CORE
STEEL FACEPLATES
POLYURETHANE CORE
STEEL FACEPLATES
SPS Introduction
Design Approach
Element Validation
ANSYS Models
GT STRUDL ModelsComparison
SPS for Civil Structures
Introduction to SPS
• Developed by Intelligent Engineering– Maritime industry– Bridge Application (deck)
Pre-fab Panels
Disadvantages– Cost– Limited application– No design provisions
Advantages– Lightweight– Rapid installation– New/rehab
Prefabricated Decks/Bridges
• Fabricated panel – limited girder configuration• Wide girder spacing • Larger cantilevers• Fast erection
Structured Panel Deck
Slip-Critical Bolt
WeldedConnection
Cold-FormedAngle
Built-up orWide Flange
Section
Polymer Core(Unexposed)Steel Face Plates
Panel Edge Plate(Cold-Formed Angle)
Half-Scale Bridge (VT Laboratory)• Span ≈ 40 ft; width ≈ 14.75 ft• Deck ≈ 1 in. (3.2-19.1-3.2)• 8 SPS panels
– Transversely welded/bolted– Bolted to girders (composite)
• 2 girder construction
4'-10" 5'-1" 4'-10"
Top Flange PlatePL 0.625 x 6 x 480
Bottom Flange PlatePL 1 x 6.4 x 480
Diaphragm Angles 2 x 2 x 0.31
Top and BottomSandwich Plate
PL 0.125 x 60 x 177.2
Girder WebPL 0.25 x 21.4 x 480
Elastomer Core0.75 x 60 x 177.2
Bent AnglePL 0.19 x 7.9 x 177.2
Shenley Bridge (St. Martin, QC)
• Completed - November 2003– 7 days of total construction
• Span ≈ 74 ft; width ≈ 23 ft• Deck ≈ 2 in. (6.4-38-6.4)• 10 SPS panels
– Transversely welded/bolted– Bolted to girders (composite)
• 3 girder construction
LAY PANELSERECT GIRDERS& BRACING
Sequence of SPS Construction
BOLT PANELS TO BEAMS & TOGETHER
WELD DECK SEAM
COAT DECKERECT BARRIERS
Sequence of SPS Construction
LAY ASPHALT
Prefabricated Decks/Bridges
• Simple plate – many girder configuration• Small girder spacing• Short cantilevers• Girders attached to deck in factory• Very fast erection
Simple Plate Deck
WeldedConnection
Wide FlangeSection
Polymer Core(Unexposed)Steel Face Plates
Cedar Creek Bridge (Wise County, TX)
• 2-Lane rural road• SPS Deck (integral girders)• Span = 3@50 ft• Width = 30 ft• Deck ≈ 1-5/8 in.
• 5/16”-1”-5/16”
CL OFBRIDGE
SEEDET "3"
2% SLOPESPS 516" - 1" - 5/16"
DET "A"SEE
32'-414"
10'-0"
30'-0"
2% SLOPE
6'-218" 10'-0"6'-21
8"
CLEAR ROADWAYCL OF
BRIDGE
SEE DET "1"GUARDRAIL
6'-314" 6'-31
4" 6'-314" 6'-31
4"6'-314"
DET "2"SEE
C 15 x 33.9C 15 x 33.9C 15 x 33.9 C 15 x 33.9C 15 x 33.9
NOTE SPACING IS AT TOP & CTROF GIRDER TOP FLANGE
2%TYP
2%TYP
Fabrication Process
Current Bridge Projects New Bridge IBRC – Cedar Creek – Texas – June ‘08
Research Objective
• To develop a simple design procedure for SPS decks for bridge applications
SPS Deck Design ApproachAASHTO Deck Design• Design Methods
– Linear Elastic (Equivalent Strip)– Inelastic (Yield-Line)– Empirical (R/C only)– Orthotropic Plate
• Limit States– Serviceability– Strength– Fatigue
SPS Approach (Layered Plate)– Variable loads and B.C.s– Assume deflection controls
Plastic hinges
Strip W
idth (
S)
Equivalent Strip
Equivalent Strip on Rigid Girders
Slab-Girder Bridge
Slab Section Cut-out
Arbitrary Loading
Deck Continuity
Cut-out
Plate Representation of Bridge Deck
Edge BCsSimplified
Edge BCsSimplified
Arbitrary Loading
Slab-Girder Bridge
Slab Section Cut-out
Arbitrary Loading
Deck Continuity
Cut-out
Plate Representation of Bridge Deck
Edge BCsSimplified
Edge BCsSimplified
Arbitrary Loading
Simple Support Fixed Support
Traffic Direction
SPS Plate Representation
Analysis Options
• Classical Plate Approach– Navier– Levy– Energy (Ritz)
• Finite Element Approach– Shell– Solid– Grid (line elements)
Approach primarily dependent on B.C.s
FE Model Approach• Shell Model
– Advantages• Ideal for thin elements• Computationally efficient• Membrane/bending effects• Single thru thickness element
• Solid Model– Advantages
• Realistic geometry representation
• Element connectivity
– Disadvantages• Element compatibility• Element connectivity• Stacking limitations*
– Disadvantages• Can be overly stiff• User error (more likely)• Complicated mesh refinement
Material Properties
Face Plates (Steel)
Core (Polyurethane) Composite Section
Young’s Modulus (E -ksi)
29,878 109
Poisson’s Ratio () 0.287 0.36
Flexural Rigidity
(D)N/A
3 3 3
22
2 22 23 11
c c cp
t p ccp
t t ttD E E
3 33
2 2
2 22 23 1 1
c ccp p p
c c
eqt p c
t t tE t E
D
2
3
12 1t eqequiv
total
DE
t
*Dt = flexural rigidity for layered plate (equivalent to EI for a beam)
*Ventsel, E., and Krauthammer, T. (2001). Thin plates and shells:theory, analysis, and applications, Marcel Dekker, New York, NY.
tp
tc
tp
a
b
q
Fixed Edge
Element Validation (Generic)Givens:
– Boundary Conditions: Fully Restrained– Material Properties: E=29,000 ksi; =0.25 – Dimensions: thickness=6” (constant); a=b=L [L/t … 1-200]– Load: q = 0.01 ksi (uniform)
ANSYS• Shell 63 (4-node)• Shell 91/93 (8-node)• Solid 45 (8-node)• Solid 95, Solid 191 (20-node)
GT STRUDL• BPR (4-node plate)• SBHQ6 (4-node shell)• IPLS (8-node solid)• IPQS (20-node solid)
40.00126classical
q LwD
Midpanel Deflection (wmax)
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1 10 100Span/thickness ratio (L/t)
SHELL 63 SHELL 91 / 93 SOLID 45 SOLID 95 / 191IPLS IPQS BPR SBHQ6
Convergence Comparison of ANSYS and STRUDL Elements (Square Fixed Plate with Uniform Load )
wm
idsp
an(F
E)
/wm
idsp
an(c
lass
ical
) Shell 91 / 93
Shell 63 IPQSSolid 95 / 191
Solid 45
IPLS
BPR
SBHQ6
GT STRUDL ModelsElement Types
BPR SBHQ6
IPLS IPQS
GT STRUDL Models
Mesh VerificationIPLS Element Validation
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1 10 100 1000
L/t Ratio
dFE
A/d
CLA
SS
ICA
L
IPLS 6x6x6
IPLS 3x3x3
IPLS 2x2x2
IPLS 1x1x1
IPLS 2x2x1
GT STRUDL Models
Two Dimensional Example
60 in.
60 in.
IPLQ(2D equivalent of IPLS)Linear Shape Function
IPQQ(2D equivalent of IPQS)
Quadratic Shape Function
A shape function is the relationship of displacements within an element.
GT STRUDL Models
Two Dimensional Example
60 in.
60 in.
One Layer
GT STRUDL Models
Two Dimensional Example
60 in.
60 in.
Two Layers
GT STRUDL Models
Two Dimensional Example
60 in.
60 in.
Three Layers
GT STRUDL Models
Two Dimensional Example
60 in.
60 in.
Four Layers
GT STRUDL Models
Two Dimensional Example
120 in.
120 in.
GT STRUDL Models
2D Element Comparison Example
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
0 5 10 15 20 25
Number of Longitudinal Divisions
d FEA/d
Cla
ssic
al
IPLQ 1 Layer
IPLQ 2 Layers
IPLQ 3 Layers
IPLQ 4 Layers
Two Dimensional Example2D Element Comparison Example
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
0 5 10 15 20 25
Number of Longitudinal Divisions
d FEA/d
Cla
ssic
al
IPLQ 1 Layer
IPLQ 2 Layers
IPLQ 3 Layers
IPLQ 4 Layers
IPQQ 1 Layer
IPQQ 2 Layers
GT STRUDL Models
Aspect Ratios (IPLS vs. IPQS)
Small Aspect Ratios Large Aspect Ratios
SPS Models
• Case I– Simple Support on all edges
• Cold-formed angles – assume minimal rotational restraint
Girder Line
Girder Line
Panel Length
GirderSpacing
Simple Support Fixed Support
SPS Models• Case II
– Simple supports perpendicular to girders– Fixed supports along girders
• Rotation restrained by girders & cold-formed angles
Girder Line
Girder Line
Panel Length
GirderSpacing
Simple Support Fixed Support
SPS Models• Case III
– Full restraint on all edges• Rotation restrained by girders & cold-formed angles
GirderSpacing
Panel Length
Girder Line
Girder Line
Simple Support Fixed Support
GT STRUDL Models
Boundary Conditions/SymmetryFull Model:
345,600 Elements406,567 Joints1,229,844 DOF
Reduced Model:
86,400 Elements102,487 Joints307,461 DOF
GT STRUDL Models
• Simple – Simple• Simple – Fixed• Fixed – Fixed• 2” Thick Plate• 1” Thick Plate• Symmetry
Model Construction
GT STRUDL Models
Model Construction
GT STRUDL Models
Model Construction
½” ½”
GT STRUDL Models
• Stiffness Analysis• GTSES• GTHCS
Model Construction
DPM-w-selfbrn, The module 'SPWNDX' may not be branched to recursively
The GTHCS solver partitions the global stiffness matrix into hyper-column blocks of size VBS, and stores these blocks on the computer hard drive, with only two of these blocks residing in the virtual memory at a time reducing the required amount of virtual memory space.
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1 10 100Span/thickness ratio (L/t)
SHELL 63 SHELL 91 / 93 SOLID 45 SOLID 95 / 191IPLS IPQS BPR SBHQ6
Convergence Comparison of ANSYS and STRUDL Elements (Square Fixed Plate with Uniform Load )
wm
idsp
an(F
E)
/wm
idsp
an(c
lass
ical
) Shell 91 / 93
Shell 63 IPQSSolid 95 / 191
Solid 45
IPLS
BPR
SBHQ6
Summary of Element Validity
• ANSYS Solids– Converged with single thru thickness element
• ANSYS Shells– Minimal mesh refinement required for convergence
• STRUDL Plate/Shells– Converged but no multiple layer capabilities
• STRUDL Solids– Converged with sufficient thru thickness refinement
All Elements are capable of Modeling thin plates, but consideration must be given to mesh density. Especially, thru thickness density for solid elements
Suggested Improvements
• Layered element for composite materials• Redraw Issues in GT Menu• Contour plots without mesh• Undo Button in GT Menu
Model Validation – SPS Panel
Full Scale SPS Panel
Model Validation – SPS Panel
10'-0"
9'-9" 10'-0" 9'-9"
5'-11"
2'-1" 2'-1"
• SPS Plate (0.25” plates; 1.5” core)• Support by W27 x 84 beams• Loaded to 77.8 k with concrete filled tires (assumed 10” x 20”)
Experimental vs. Shell Model PredictionsANSYS
0
10
20
30
40
50
60
70
80
90
-0.6-0.5-0.4-0.3-0.2-0.10.0
App
lied
Load
(kip
)
Deflection (in.)
Measured SS Plate (Case I) Fixed @ Beams (Case II) Fully Fixed (Case III)
Load vs. Mid-panel Deflection - Full-Scale Panel (ANSYS)
Case III Case IICase I
Experimental vs. Shell Model PredictionsANSYS
Experimental vs. Solid Model PredictionsANSYS
0
10
20
30
40
50
60
70
80
90
-0.6-0.5-0.4-0.3-0.2-0.10.0
App
lied
Load
(kip
)
Deflection (in.)
Measured SS Plate (Case I) Fixed @ Beams (Case II) Fully Fixed (Case III)
Load vs. Mid-panel Deflection - Full-Scale Panel (ANSYS)
Case III Case IICase I
Experimental vs. Solid Model PredictionsGT STRUDL
Experimental vs. Solid Model PredictionsGT STRUDL
0
10
20
30
40
50
60
70
80
90
-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.10.0
App
lied
Load
(kip
)
Deflection (in.)
Measured SS Plate (Case I) Fixed @ Beams (Case II) Fully Fixed (Case III)
Load vs. Mid-panel Deflection - Full-Scale Panel (GT STRUDL)
Case III Case II Case I
Model Validation – SPS Bridge
Half-Scale SPS Bridge
Model Validation – SPS Bridge
• SPS Plate (0.125” plates; 0.75” core)• Support by Built-up Girders (depth ~ 23”)• Loaded ~ 24 k with bearing pad (9” x 14”)
9 3,6,8
GIRDER "B"
GIRDER "A"
XX= STRAIN GAGES
X = DISPLACEMENT TRANSDUCERS (WIRE POT OR DIAL GAGE)= STRAIN GAGES LOCATED ON OPPOSITE FACE
"G" "G"
ELEVATION "G-G"
4,5
13
4
61,22
63
4
5
6
5
2
40 ft
4.84
ft5.
09 ft
4.84
ft
17
12 3
9 78
5 ft
5
7
4 7
Panel 1 Panel 2 Panel 3 Panel 4 Panel 5 Panel 6 Panel 7 Panel 8
Experimental vs. Shell Model PredictionsANSYS
Experimental vs. Shell Model PredictionsANSYS
0
5
10
15
20
25
30
-0.7-0.6-0.5-0.4-0.3-0.2-0.10
Load
(kip
)
Midspan Deflection (in.)
Measured SS Plate (Case I) Fixed @ Beams (Case II) Fully Fixed (Case III)
Case II Case I
Load vs. Mid-panel Deflection - Half-Scale Bridge (ANSYS)
Case III
Experimental vs. Solid Model PredictionsANSYS
0
5
10
15
20
25
30
-0.7-0.6-0.5-0.4-0.3-0.2-0.10
Load
(kip
)
Midspan Deflection (in.)
Measured SS Plate (Case I) Fixed @ Beams (Case II) Fully Fixed (Case III)
Case IICase I
Load vs. Mid-panel Deflection - Half-Scale Bridge (ANSYS)
Case III
Experimental vs. Solid Model PredictionsGT STRUDL
Experimental vs. Solid Model PredictionsGT STRUDL
0
5
10
15
20
25
30
-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.10
Load
(kip
)
Midspan Deflection (in.)
Measured SS Plate (Case I) Fixed @ Beams (Case II) Fully Fixed (Case III)
Case IICase I
Load vs. Mid-panel Deflection - Half-Scale Bridge (GT STRUDL)
Case III
Comparison of ANSYS and GT STRUDL Models
0
0.25
0.5
0.75
SPS Panel SPS Bridge
Maximum SPS Panel Deflections @ Peak LoadMeasured vs. FEA
Measured GT STRUDL Solid ANSYS Shell ANSYS Solid
Conclusions• SPS deck behavior can be modeled as plate with
variable boundary conditions• Solid and shell elements are applicable• Attention to mesh refinement critical to solid elements
• Higher order elements significantly increase # DOFs
• Layered elements ideal for efficiency• GT STRUDL and ANSYS yield similar results, but not
identical– Future investigation of differences in solid/shell boundary
conditions
Acknowledgements
• Virginia Department of Transportation• Intelligent Engineering (www.ie-sps.com)• GT STRUDL Users’ Group• Virginia Tech