Presentation on theme: "Devin Harris – Michigan Tech Chris Carroll – Virginia Tech"— Presentation transcript:
1Devin Harris – Michigan Tech Chris Carroll – Virginia Tech Evaluation of the Sandwich Plate System in Bridge Decks Using a Plate ApproachA Comparison Between ANSYS and GT STRUDL ModelsDevin Harris – Michigan TechChris Carroll – Virginia Tech
6Half-Scale Bridge (VT Laboratory) Span ≈ 40 ft; width ≈ ftDeck ≈ 1 in. ( )8 SPS panelsTransversely welded/boltedBolted to girders (composite)2 girder construction
7Shenley Bridge (St. Martin, QC) Completed - November 20037 days of total constructionSpan ≈ 74 ft; width ≈ 23 ftDeck ≈ 2 in. ( )10 SPS panelsTransversely welded/boltedBolted to girders (composite)3 girder construction
8Sequence of SPS Construction ERECT GIRDERS& BRACINGLAY PANELSBOLT PANELS TO BEAMS & TOGETHERWELD DECK SEAM
9Sequence of SPS Construction ERECT BARRIERSCOAT DECKLAY ASPHALT
10Prefabricated Decks/Bridges Simple Plate DeckSimple plate – many girder configurationSmall girder spacingShort cantileversGirders attached to deck in factoryVery fast erection
11Cedar Creek Bridge (Wise County, TX) 2-Lane rural roadSPS Deck (integral girders)Span = ftWidth = 30 ftDeck ≈ 1-5/8 in.5/16”-1”-5/16”
17Approach primarily dependent on B.C.s Analysis OptionsClassical Plate ApproachNavierLevyEnergy (Ritz)Finite Element ApproachShellSolidGrid (line elements)Approach primarily dependent on B.C.sNote: Focus here will be on the FE approach, but the classical plate approach will be used primarily as a validation mechanism17
18FE Model Approach Shell Model Solid Model Advantages Disadvantages Ideal for thin elementsComputationally efficientMembrane/bending effectsSingle thru thickness elementSolid ModelRealistic geometry representationElement connectivityDisadvantagesElement compatibilityElement connectivityStacking limitations*Can be overly stiffUser error (more likely)Complicated mesh refinement
19Material Properties Face Plates (Steel) Core (Polyurethane) Composite SectionYoung’s Modulus(E -ksi)29,878109Poisson’s Ratio (n)0.2870.36Flexural Rigidity (D)N/A*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.
24GT STRUDL Models Two Dimensional Example IPLQ (2D equivalent of IPLS) Linear Shape Function60 in.A shape function is the relationship of displacements within an element.IPQQ (2D equivalent of IPQS) Quadratic Shape Function60 in.
25GT STRUDL ModelsTwo Dimensional Example60 in.One Layer60 in.
26GT STRUDL ModelsTwo Dimensional Example60 in.Two Layers60 in.
27GT STRUDL ModelsTwo Dimensional Example60 in.Three Layers60 in.
28GT STRUDL ModelsTwo Dimensional Example60 in.Four Layers60 in.
29GT STRUDL ModelsTwo Dimensional Example120 in.120 in.
39GT STRUDL Models Model Construction Stiffness Analysis GTSES GTHCS 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.DPM-w-selfbrn, The module 'SPWNDX' may not be branched to recursively
41Summary of Element Validity ANSYS SolidsConverged with single thru thickness elementANSYS ShellsMinimal mesh refinement required for convergenceSTRUDL Plate/ShellsConverged but no multiple layer capabilitiesSTRUDL SolidsConverged with sufficient thru thickness refinementAll Elements are capable of Modeling thin plates, but consideration must be given to mesh density. Especially, thru thickness density for solid elements
42Suggested Improvements Layered element for composite materialsRedraw Issues in GT MenuContour plots without meshUndo Button in GT Menu
43Model Validation – SPS Panel Full Scale SPS Panel
44Model Validation – SPS Panel SPS Plate (0.25” plates; 1.5” core)Support by W27 x 84 beamsLoaded to 77.8 k with concrete filled tires (assumed 10” x 20”)
45Experimental vs. Shell Model Predictions ANSYS CASE II Beams)CASE I (SS)CASE III (Fixed)
58Questions Conclusions SPS deck behavior can be modeled as plate with variable boundary conditionsSolid and shell elements are applicableAttention to mesh refinement critical to solid elementsHigher order elements significantly increase # DOFsLayered elements ideal for efficiencyGT STRUDL and ANSYS yield similar results, but not identicalFuture investigation of differences in solid/shell boundary conditionsQuestions
59Acknowledgements Virginia Department of Transportation Intelligent Engineering (www.ie-sps.com)GT STRUDL Users’ GroupVirginia Tech