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General

The geometry, start and end locations of the deck are primarily determined based on the selected girders. Support lines, on the other hand, are only used to define the cross-section location.

Cross-Sections:

  • Cross Section Location(Support Line): To extrude the section, the user needs to input the deck cross-section location and can introduce linear or parabolic variations between the cross-sections. It is crucial to note that at least two cross-section definitions are required.

  • Offset From Support Line[ft]: If the entered cross-section is not located at the selected support line, use the offset value.

  • Cross Section: Select the cross-section defined prior to this step.

  • Skew Angle[deg]: A positive skew value rotates the start and end location in a clockwise direction, while a negative skew value rotates the cross-section counterclockwise. Selecting a skew value for any interior support line (pier) will impact the finite element generation logic at that location.

  • Variation w/Next Segment[Linear/Parabola]:

Girders: To create the 3D geometry for the haunch and finite element mesh of the deck, input for the girder is required. To ensure accurate extraction of composite forces, the library component will generate a minimum of two shell elements between two girders.

Taper: In the overhang regions, users can choose whether or not to include taper by selecting "yes" or "no," as shown in the figure below. This input will impact the haunch load computation.


Material: The material used for the shell elements generated for the deck.

Deck Reinforcement Data

The reinforcement data for the deck will be automatically utilized in the code checking process for the superstructure elements.

  • Start Station:

  • End Station:

  • Deck Rebar Material:

  • Longitudinal Deck Rebar Spacing (Top Layer):

  • Longitudinal Deck Rebar Spacing (Bottom Layer):

  • Longitudinal Deck Rebar (Top Layer):

  • Longitudinal Deck Rebar (Bottom Layer):

  • Transverse Deck Rebar (Top Layer):

  • Transverse Deck Rebar (Bottom Layer):

  • Clear Cover (Top) :

  • Clear Cover (Bottom) :

  • Concrete creep adjustment factor: To incorporate the effects of concrete creep in stress calculations that involve the application of long-term loads to the composite section in regions of negative flexure, the area of the longitudinal reinforcement can be conservatively adjusted by dividing it by the "Concrete creep adjustment factor." The concrete is assumed to transfer the force from the longitudinal deck steel to the rest of the cross-section, with concrete creep acting to reduce that force over time. It is important to note that assuming a value greater than 1 is a conservative approach and is not mandated by the AASHTO LRFD BDS. As such, it is not recommended to use this assumption in normal design practice. When using the default value of 1, the reinforcement area will remain unaltered.

FEA

Expansion Joint End Releases: The deck mesh will create two nodes at the same location for the entered station and connect them with springs. Spring stiffness will be assigned based on the values entered by the user in respective directions. This is another way to model discontinuous decks, expansion joints, or even hinges.

  • Station: Station of the end release or expansion joint.

  • Tx-Ty-Tz-Rx-Ry-Rz: Utilize a "free" or a small stiffness value in the direction where you wish to enable release. For instance, you can set Tx, Ty, Rx, Ry, and Rz as "free," while keeping Tz as "fixed." In case stability issues arise, using a small stiffness value in the direction causing instability can be a helpful solution.

Deck Property Overrides: If you wish to override the thickness or material properties of the deck FE surface elements in specific regions, utilize property overrides.

  • Override Thickness[Yes/No]

  • Thickness: Enter the overridden thickness value.

  • Override Material[Yes/No]

  • Material: Select 'Override Material.

  • Mesh at Override Boundary[Yes/No]: If you wish to apply additional constraints to the mesh at the boundary you've defined for override, choose 'Yes.' Typically, selecting 'Yes' can overly complicate the meshing process, so opt for 'No' if it doesn't significantly impact your results.

  • Longitudinal & Transverse Boundary: Choose the longitudinal and transverse boundaries for the override region.

Continuous at Start-Continuous at End[Yes/No]: Users can choose whether the deck is continuous or discontinuous at the start or end regions, which affects the generation of the finite element model. To ensure continuity between two different decks, users can select the "continuous" option for the end location of the first deck and the start location of the second deck. If the user wants to define the deck as discontinuous with a gap between two decks, they can select the "discontinuous" option and define girders end locations accordingly. Selecting continuous or discontinuous options will not affect the behavior if only one deck is defined.

3D Settings

Curve Refinement: The curve refinement parameter is employed to discretize the deck along the longitudinal direction. This parameter is only applicable to the 3D view and does not affect the FEA model. If you do not observe a smooth curve, increasing this value can be helpful.

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