Analyse different anchorage solutions using advanced nonlinear...
Transcript of Analyse different anchorage solutions using advanced nonlinear...
1. Webinar Purpose
2. Introduction to midas FEA
3. Reference Material
4. Analysis Details
5. Results
6. Conclusion
7. Future Research Possibilities
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• Analyse different anchorage solutions using advanced nonlinear numerical models
• Compare stress distribution to theoretical models
• Check crack distribution
• Compare crack distribution considering:• High Strength Concrete(C90/105) vs. UHPFRC (G2TM)
• Plain concrete vs. Reinforced concrete
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• midas FEA is state of the art software which defines a new paradigm for advanced nonlinear and detail analysis for civil and structural engineering applications;
• It is specialized for refined method analysis, which is required by design codes for complex geometry;
• Able to perform local analysis for elements and obtain in-depth and highly accurate calculations that are essential for projects that require refined method analyses.
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01. Linear Static Analysis
• Multiple Load Cases & Combinations
• Output Control (Data, Node, Element)
• Result Coordinate System
• Extensive Element Library
• Equation Solvers• Direct Solvers
• Multi-frontal Sparse Gaussian Solver
• Skyline Solver
• Iterative Solvers• PCG, GMR (Unsymmetric)
• Construction Stage Analysis• Material Nonlinearity
• Restart
02. Nonlinear Static Analysis
• Material Nonlinearity• von Mises, Tresca, Mohr-Coulomb,
• Drucker-Prager, Rankine,
• User Supplied Material
• Geometric Nonlinearity• Total Lagrangian
• Co-rotational
• Iteration Method• Full Newton-Raphson
• Modified Newton-Raphson
• Arc-Length Method
• Initial Stiffness
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03. Reinforcement Analysis
• Reinforcements• Embedded Bar
• Embedded Grid
• Various Mother Elements (Solid, Plate, Axisymmetric, etc.)
• Prestress (Pre-tensioned & Post-tensioned)
• Material Nonlinearity
• Geometric Nonlinearity
04. Crack Analysis
• Total Strain Crack• Fixed & Rotating Crack Model
• Discrete Drack Model• Interface Nonlinearity
• Results• Crack Pattern
• Element Status(Crack, Plasticity)
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05. Eigenvalue Analysis
• Modal Analysis• Lanczos Method
• Subspace Iteration
• Sturm-Sequence Check
• Include Rigid Body Modes
• Modal Participation Factors
• Linear Buckling Analysis• Critical Load Factors
• Buckling Modes
• Load Combinations & Factors
06. Dynamic Analysis
• Transient / Frequency Response• Direct Integration
• Mode Superposition
• Time Forcing Function DB
• Time Varying Loads
• Ground Acceleration
• Time History Plot / Graph
• Spectrum Response• SRSS, CQC, ABS
• Design Spectrum DB
• Seismic Data Generator
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07. Interface Nonlinear Analysis
• Interface Elements
• Point, Line, Plane
• Pile (Solid-Line)
• Interface Models
• Rigid
• Coulomb Friction
• Discrete Cracking
• Crack Dilatancy
• Bond-Slip
• Combined CSC
08. Contact Analysis
• Contact Type
• Weld Contact, General Contact
• Behaviors
• Material Nonlinearity
• Geometry Nonlinearity
• Result
• Displacement
• Stress
• Contact force
09. Fatigue Analysis
• Methods and Parameters
• S-N Method (Stress-Life)
• Load / Stress History
• Rainflow Counting
• Mean Stress Corrections
• Stress Concentration Factor
• Modifying Factors
• Results
• Cycles to Failure
• Damage estimation
10. Heat of Hydration Analysis
• Heat Transfer
• Steady-State / Transient
• Heat Generation
• Conduction
• Convection
• Pipe Cooling
• Concrete Behavior
• Creep / Shrinkage
• Compressive Strength
• Design Codes (JCI, JSCE, etc.)
11. Heat Transfer/Stress Analysis
• Steady-State & Transient
• Conduction, Convection
• Heat Flux
• Heat Flow
• Temperature Gradient Display
12. CFD Analysis
• CFD Models• Turbulence Models
• Compressible/ Incompressible Flow
• Inviscid Flow
• Unsteady Flow
• Discretization Scheme• 2nd-order (Spatial)
• Dual time stepping (Temporal)
• Boundary Conditions
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• EUROCODE 2
• CIRIA: A guide to the design of anchor blocks for post-tensioned concrete members
• Structural Implications of Ultra-High Performance Fibre-Reinforced Concrete in Bridge Design, Ana Spasojević (2008)
• Ultra High Performance Fibre-Reinforced Concretes: Interim Recommendations, AFGC-SETRA (2002)
• Testing and analysing innovative design of UHPFRC anchor blocks for post-tensioning tendons, F. Toutlemonde, J.-C. Renaud & L. Lauvin
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Geometry Material Properties
• Two separate cases:• High Strength Concrete: C90/105
• Ultra High Performance Fiber Reinforced Concrete: Ductal G2TM
• In both cases the Total Strain Crack constitutive model will be used
• For each type of concrete two cases will be considered:• Plain concrete
• Reinforced (only bursting reinforcement modelled)
C90/105
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• Smeared crack model
• Fixed crack model: the axes of cracks remain unchanged once the crack axes are defined
• Rotating crack model: the directions of the cracks are assumed to continuously rotate depending on the changes in the axes of principle strains
• Secant stiffness: suitable for finding excellent and stable solutions to analyses of reinforced concrete structures, which widely develop cracks
• Tangent stiffness: very appropriate for analyses of local cracking or crack propagation
C90/105
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• In cracked concrete, large tensilestrains perpendicular to the principal compressive direction reduce the concrete compressive strength
• The compressive strengths is dependent on the lateral damage variables
• Accounts for increase in strength given by lateral confinement
• The increased ductility of confined concrete is modelled by a linear adoption of the descending branch of the Thorenfeldt curve
C90/105
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• Hordijk Model
• Expresses tension softening behaviour of concrete
• Results in a crack stress equal to zero at ultimate crack strain
• Thorenfeldt Model
Mechanical characteristics at 28 days
Characteristic compressive strength f_ck 150.00 MPa
Characteristic limit of elasticity under tension f_ctk,el 8.00 MPa
Characteristic maximal post-cracking stress f_ctfk = σ_(0,3) 6.10 MPa
Mean Young’s modulus E_cm 53000.00 MPa
Poisson’s ratio 0.20
Other characteristics
Density 24 to 25 kN/m^3
Thermal expansion coefficient at 28 days 11.00 μm/m/°C
Autogenous shrinkage from 0 to 90 days ≤0.5 mm/m
Drying shrinkage from 0 to 90 days ≤0.3 mm/m
Creep coefficient 1.00
Durability characteristics
Water porosity at 90 days 1.5 to 2.5 %
Oxygen permeability at 28 days (at 20°C) ≤6*10^(-19) m^2
Chloride ions diffusion coefficient ≤0.5*10^(-12) m^2*s^(-1)
Mercury porosity at 90 jours 3 to 5 %
Carbonation thickness (natural and accelerated conditions) ≤0.1 mm
Resistance to freeze / thaw cycles (severe conditions – 300 cycles) 100.00 %
Resistance to spalling (de-icing salts - 56 cycles) ≤10 g/m^2
Resistance to hydraulic abrasion (CNR coefficient) 1.00
Impact resistance (CNR print testing) 65.00
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Ductal G2TM
Compression curve Tension curve
StrainStress [MPa]
StrainStress [MPa]
0 0 0 0
f_cd -0.00169811 -90 f_ctfk/K 6.39E-05 3.388889
ε_u,pic 6.80E-04 3.388889
K_local 1.8 ε_lim 5.25E-03 0
B500C
• Two reinforcement spirals• Spiral 1 Diameter: 200mm
• Spiral 2 Diameter: 250mm
• Bar diameter: 10mm
• As per CIRIA:• Spiral diameter ≥ anchorage(2ypo)+50mm
• Distributed in region [0.2yo, 2yo]
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• Prestress load applied as pressure on top of bearing plate
• Total prestress load: 30strands x 180kN = 5400kN
• γP,unfav = 1.2 as per 2.4.2.2 of EC2
• Self weight applied using automated self weight function
• Supports applied as full restraints of nodes at the bottom of the anchorage block
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σ1
C90/105 no reinforcement
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C90/105 with reinforcement
UHPFRC no reinforcement UHPFRC with reinforcement
0.85Pt
σ3
C90/105 no reinforcement
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C90/105 with reinforcement
UHPFRC no reinforcement UHPFRC with reinforcement
0.85Pt
C90/105 no reinforcement
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C90/105 with reinforcement
UHPFRC no reinforcement UHPFRC with reinforcement
0.85Pt 0.95Pt
C90/105 no reinforcement
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C90/105 with reinforcement
UHPFRC no reinforcement UHPFRC with reinforcement
0.85Pt 0.95Pt
UHPRFC no reinforcement
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-100
-80
-60
-40
-20
0
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-2.00E-03 -1.00E-03 0.00E+00 1.00E-03 2.00E-03 3.00E-03 4.00E-03 5.00E-03 6.00E-03
Stress [MPa]
Strain [mm/mm]
Stress-Strain Diagram G2TM
G2TM
Elem. 102925 (Max Stress, Strain)
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C90/105 reinforcement Stress C90/105 reinforcement Strain
UHPFRC reinforcement Stress UHPFRC reinforcement Strain
• Bursting reinforcement has a very beneficial effect for HSC
• The reinforcement has little to no effect on the crack distribution for UHPFRC
• UHPFRC shows a more even distribution of stresses compared to HSC
• The fibers have a very beneficial effect on crack distribution, helping to keep the crack dimensions limited
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• Check theoretical models against tests on UHPFRC samples
• Improve calibration of models from tests on UHPFRC samples
• Implement UHPFRC models and databases as standard for finite element software
• Better implementation of UHPFRC into current design standards, as current codes tend to be ultra conservative
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Contact us at:
+44 (0)207 559 1389
Visit our website at:
uk.midasuser.com
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