Evaluation of the Sandwich Plate System in Bridge Decks Using a Plate Approach

Devin Harris Michigan TechChris Carroll Virginia TechA Comparison Between ANSYS and GT STRUDL Models

Project OverviewSPS Introduction

SPS for Civil Structures

Introduction to SPSDeveloped by Intelligent EngineeringMaritime industryBridge Application (deck)Pre-fab PanelsDisadvantagesCostLimited applicationNo design provisionsAdvantagesLightweightRapid installationNew/rehab

Prefabricated Decks/BridgesFabricated panel limited girder configurationWide girder spacing Larger cantileversFast erectionStructured Panel Deck

Half-Scale Bridge (VT Laboratory)Span 40 ft; width 14.75 ftDeck 1 in. (3.2-19.1-3.2)8 SPS panelsTransversely welded/boltedBolted to girders (composite)2 girder construction

Shenley Bridge (St. Martin, QC)Completed - November 20037 days of total constructionSpan 74 ft; width 23 ftDeck 2 in. (6.4-38-6.4)10 SPS panelsTransversely welded/boltedBolted to girders (composite)3 girder construction

LAY PANELSERECT GIRDERS& BRACINGSequence of SPS ConstructionBOLT PANELS TO BEAMS & TOGETHERWELD DECK SEAM

COAT DECKERECT BARRIERSSequence of SPS ConstructionLAY ASPHALT

Prefabricated Decks/BridgesSimple plate many girder configurationSmall girder spacingShort cantileversGirders attached to deck in factoryVery fast erectionSimple Plate Deck

Cedar Creek Bridge (Wise County, TX)2-Lane rural roadSPS Deck (integral girders)Span = 3@50 ftWidth = 30 ftDeck 1-5/8 in.5/16-1-5/16

Fabrication Process

Current Bridge Projects New Bridge IBRC Cedar Creek Texas June 08

Research ObjectiveTo develop a simple design procedure for SPS decks for bridge applications

SPS Deck Design ApproachAASHTO Deck DesignDesign MethodsLinear Elastic (Equivalent Strip)Inelastic (Yield-Line)Empirical (R/C only)Orthotropic PlateLimit StatesServiceabilityStrengthFatigueSPS Approach (Layered Plate)Variable loads and B.C.sAssume deflection controls

SPS Plate Representation

Analysis OptionsClassical Plate ApproachNavierLevyEnergy (Ritz)Finite Element ApproachShellSolidGrid (line elements)Approach primarily dependent on B.C.s

FE Model ApproachShell ModelAdvantagesIdeal for thin elementsComputationally efficientMembrane/bending effectsSingle thru thickness elementSolid ModelAdvantagesRealistic geometry representationElement connectivity

DisadvantagesElement compatibilityElement connectivityStacking limitations*

DisadvantagesCan be overly stiffUser error (more likely)Complicated mesh refinement

Material Properties*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.

Face Plates (Steel)Core (Polyurethane)Composite SectionYoungs Modulus (E -ksi)29,878109Poissons Ratio (n)0.2870.36Flexural Rigidity (D)N/A

Element Validation (Generic)Givens:Boundary Conditions: Fully RestrainedMaterial Properties: E=29,000 ksi; n=0.25 Dimensions: thickness=6 (constant); a=b=L [L/t 1-200]Load: q = 0.01 ksi (uniform)

ANSYSShell 63 (4-node)Shell 91/93 (8-node)Solid 45 (8-node)Solid 95, Solid 191 (20-node)

GT STRUDLBPR (4-node plate)SBHQ6 (4-node shell)IPLS (8-node solid)IPQS (20-node solid)

GT STRUDL ModelsElement TypesBPRSBHQ6IPLSIPQS

GT STRUDL ModelsMesh Verification

Chart1

0.004380.004030.00080.000810.000810.003990.004110.004130.00469

0.00480.00470.002210.002290.00230.004740.004810.004830.00469

0.004730.004710.00350.003720.003770.004830.004880.00489

0.004710.004710.004110.004430.004510.004860.00490.0049

0.00470.004710.00430.004660.004740.004871.51.5

BPR

SBHQ6

IPLS 1

IPLS 2

IPLS 3

IPQS 1

IPQS 2

IPQS 3

Theoretical

Mesh Refinement

Sheet1

BPRSBHQ6IPLS 1IPLS 2IPLS 3IPQS 1IPQS 2IPQS 3

240.004380.004030.00080.000810.000810.003990.004110.00413

120.00480.00470.002210.002290.00230.004740.004810.00483

60.004730.004710.00350.003720.003770.004830.004880.00489

30.004710.004710.004110.004430.004510.004860.00490.0049

1.50.00470.004710.00430.004660.004740.00487

300.00469

00.00469

Chart2

0.84562022341.05020576131.11158142271.33662551441.12863021751.00907554381.0039609053

0.74652410350.94450323340.99714138741.03358318641.02974720751.00527952311.0041740153

0.72024498460.91787781080.9684914205401.00911949771.003439971.0042082181

0.71562842480.91323921660.9634226599601.00415033641.00200379031.0042148059

0.7134188070.91172426150.9617501539801.00334821430.99341486181.0042176602

0.71281249850.91107668431001001.0031272193

0.71202118610.91051926871501501.0031388293

0.71174396532002002001.0032761618

IPLS 1 layer

IPLS 2 layers

IPLS 3 layers

IPLS 6 layers

IPQS

BPR

SBHQ6

IPLS

0.84562022341.05020576131.11158142271.33662551441.1286302175

0.74652410350.94450323340.99714138741.03358318641.0088624339

0.72024498460.91787781080.96849142051.00230930340.978600823

0.71562842480.91323921660.9634226599600.9732493958

0.7134188070.91172426150.96175015398080

0.71281249850.9110766843100100100

0.71202118610.9105192687150150150

0.7117439653200200200200

IPLS 6x6x6

IPLS 3x3x3

IPLS 2x2x2

IPLS 1x1x1

IPLS 2x2x1

L/t Ratio

dFEA/dCLASSICAL

IPLS Element Validation

Sheet2

q0.01

D556800IPLS

thickness6 in.3 in.2in.1 in.1 in.1 in.IPQSBPRSBHQ6

L/ttLdCLAdFEdFE/dCLA1x12x23x3dFEdFE/dCLA

106600.0002930.0002480.84562022340.0003081.05020576130.0003261.11158142270.0003921.33662551440.0003311.128630217500.0003311.1286302175

2061200.0046920.0035030.74652410350.0044320.94450323340.0046790.99714138740.004851.03358318640.0047341.008862433900.0048321.02974720750.0047351.00907554380.0047111.0039609053

4062400.0750790.0540750.72024498460.0689130.91787781080.0727130.96849142050.0752521.00230930340.0734720.97860082300.07576331.00911949770.0754751.00527952310.0753921.0041740153

6063600.3800860.2720.71562842480.3471090.91323921660.3661830.96342265990.3699180.973249395800.3816631.00415033640.3813931.003439970.3816851.0042082181

8064801.2012580.8570.7134188071.0952160.91172426151.155310.961750153901.205281.00334821431.2036651.00200379031.2063211.0042148059

10066002.9327592.0905070.71281249852.6719680.911076684302.941931.00312721932.9134460.99341486182.9451281.0042176602

150690014.84709110.5714430.712021186113.5185620.9105192687014.8936931.0031388293

2006120046.92413833.3979720.7117439653047.0778691.0032761618

11

10001

450

Sheet3

GT STRUDL ModelsTwo Dimensional Example60 in.60 in.IPLQ (2D equivalent of IPLS) Linear Shape FunctionIPQQ (2D equivalent of IPQS) Quadratic Shape FunctionA shape function is the relationship of displacements within an element.

GT STRUDL ModelsTwo Dimensional Example60 in.60 in.One Layer

GT STRUDL ModelsTwo Dimensional Example60 in.60 in.Two Layers

GT STRUDL ModelsTwo Dimensional Example60 in.60 in.Three Layers

GT STRUDL ModelsTwo Dimensional Example60 in.60 in.Four Layers

GT STRUDL ModelsTwo Dimensional Example120 in.120 in.

GT STRUDL ModelsTwo Dimensional Example

Chart1

0.7037982350.69912614640.6994722270.7163869182

0.86874891850.89120089980.89734383110.8996366153

0.9146911230.940214570.94722270290.9499048278

0.93182211460.95877314410.96608409760.9689392628

IPLQ 1 Layer

IPLQ 2 Layers

IPLQ 3 Layers

IPLQ 4 Layers

Number of Longitudinal Divisions

dFEA/dClassical

2D Element Comparison Example

Chart1 (2)

0.7037982350.69912614640.6994722270.71638691820.9880169580.9945924901

0.86874891850.89120089980.89734383110.89963661530.99208340540.9972313549

0.9146911230.940214570.94722270290.94990482780.99307838730.9978802561

0.93182211460.95877314410.96608409760.96893926280.99364076830.9981830767

IPLQ 1 Layer

IPLQ 2 Layers

IPLQ 3 Layers

IPLQ 4 Layers

IPQQ 1 Layer

IPQQ 2 Layers

Number of Longitudinal Divisions

dFEA/dClassical

2D Element Comparison Example

Sheet1

IPLQ1234

ActualAct/TheoActualAct/TheoActualAct/TheoActualAct/Theo

50.162690.7040.161610.6990.161690.6990.16560.716

100.200820.8690.206010.8910.207430.8970.207960.900

150.211440.9150.217340.9400.218960.9470.219580.950

200.21540.9320.221630.9590.223320.9660.223980.969

IPQQ12

ActualAct/TheoActualAct/Theo

50.228390.9880.229910.995

100.229330.9920.230520.997

150.229560.9930.230670.998

200.229690.9940.230740.998

Sheet2

Sheet3

Chart1

0.7037982350.69912614640.6994722270.7163869182

0.86874891850.89120089980.89734383110.8996366153

0.9146911230.940214570.94722270290.9499048278

0.93182211460.95877314410.96608409760.9689392628

IPLQ 1 Layer

IPLQ 2 Layers

IPLQ 3 Layers

IPLQ 4 Layers

Number of Longitudinal Divisions

dFEA/dClassical

2D Element Comparison Example

Chart1 (2)

0.7037982350.69912614640.6994722270.71638691820.9880169580.9945924901

0.86874891850.89120089980.89734383110.89963661530.99208340540.9972313549

0.9146911230.940214570.94722270290.94990482780.99307838730.9978802561

0.93182211460.95877314410.96608409760.96893926280.99364076830.9981830767

IPLQ 1 Layer

IPLQ 2 Layers

IPLQ 3 Layers

IPLQ 4