Slab Action
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Select the load distribution system assumed in the
slab or deck:
In some aspects the modeling requirements differ
between the two. Because of the specialized nature of the One-way analysis, the
modeling requirements for One-way decks are generally more stringent, as
described below. In many cases the modeling commands are tailored to these
requirements. Only One-way decks should be assigned to steel framing.
Two-way decks should never be assigned to
areas of steel framing. The analysis of Two-way decks is performed in
RAM Frame for the purpose of calculating
the gravity loads on the frame members, and in RAM Concrete; it is not
performed in RAM Steel. Hence, any loads on Two-way decks would not get
distributed to steel framing.
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Orientation
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(One-Way slab action) Used to specify the direction
that surface loads are distributed to the supporting members. It is also used
in
RAM Steel Beam for composite beam design
and in the compression flange bracing criteria.
- - span the
global Y direction
- - span the
global X direction
- - span the at
the specified
Angle (between 0 and 180 degrees),
measured counter-clockwise from the global X direction (horizontal on the
screen)
- Parallel To -
click
Pick to associate a member or wall
parallel to the deck span
- Perpendicular
To - click
Pick to associate a member or wall
perpendicular to the deck span
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Drop Cap
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(Two-Way slab action) Drop Caps are areas decking
around columns that have different properties. (Typically, they are thicker
than the surrounding decking.)
Each Drop Cap is attached to the top of a specific column. If that
column moves, the drop cap moves with it. If the column is deleted, the drop
cap is deleted as well. Multiple drop caps may be assigned to a single column.
If this is done, they behave just like regular decking, in that the last one
added is takes precedence over any drop caps underneath it.
Drop Caps behave exactly the same as regular
decking, with the following exceptions:
- They are attached to
a column and consequently move with that column and are deleted when that
column is deleted.
- They are kept above
all regular decking, so adding regular (non drop cap) decking to the same area
after the drop cap was created results in the regular decking being
"underneath" the drop cap, meaning that the
drop cap takes precedence in the area of overlap.
- The deck show
command shows the drop cap properties for drop caps.
- The deck change
command does not allow the drop cap setting to be changed.
While drop caps are always initially square or
rectangular, the
Change
Polygon command can be used to make them any desired shape once
they have been initially created as a square or rectangle.
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Framing System
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Select the framing system used:
- Composite -
includes concrete on metal deck, precast plank, and flat slabs. Concrete
properties and shear stud information must be specified. This information is
used by the
RAM Steel Beam module to calculate the
composite section properties of composite beams. Refer to the
RAM Steel Beam manual for more
information.
- Noncomposite -
includes all other systems, such as grating, checkerplate, and roof deck
- Concrete - used
in conjunction with flat slab, flat plate, and concrete beam and column
structures
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decking / slabs table
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Lists the decks and slabs that correspond to the
current material section
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Graphics Mode
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Provides multiple tools for adding, editing,
deleting, or reviewing deck and slab assignments in the current layout.
Setting | Description |
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Whole Floor
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assigns the deck to the entire floor. It does
this by creating new points 5 ft. (1.52 m) beyond the floor dimensions in each
direction, and laying down a rectangular polygon. This ensures that the whole
floor and slab edges are covered with a deck polygon. If the floor has more
than one diaphragm, the
Whole Floor command will assign the
deck to all diaphragms on that floor.
|
Tip: Generally the best way to model
the deck assignments is to first lay the most commonly used deck over the whole
floor, using the
Whole Floor command and then overlay
the areas where other decks or deck orientation occur by using the
Add command. Exception: this may not be true for layout types with
sloping framing.
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Whole Diaphragm
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the target cursor appears with which to select
the diaphragm to which the currently selected deck properties are to be
assigned. Note a difference between the
Whole Floor and
Whole Diaphragm commands: whereas the
Whole Floor command creates a simple
rectangular polygon slightly larger than the layout, the
Whole Diaphragm creates a polygon
precisely the same as the slab edge outline. The
Whole Diaphragm command can be used on
a floor type with just one diaphragm.
Note: If the
framing on a floor type is expanded, the deck polygons originally laid down
using the
Whole Floor or
Whole Diaphragm may no longer
encompass all of the framing, and the commands may have to be repeated (or the
polygon modified as explained below).
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Add
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Click to draw a deck polygon.
For One-way decks, except at perimeter beams
with slab edges as described above, polygon sides laid down with the
Add option must lie exactly on
beams. They should not cut randomly through a bay. Two-way deck polygon sides
do not need to be laid down on beams, but can by laid out anywhere within the
slab edge.
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Add Drop Cap - Fence
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Change
|
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Change Polygon
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When using this command, first click on the
polygon to be modified, which will cause the edges and vertices of that polygon
to be highlighted. The following can then be performed:
- To move a
vertex, click on the vertex to be moved and then click on the new location.
- To add a new
vertex, move the cursor to the middle of the side on which a new vertex is
desired; a new vertex will appear. Click on it to create it. Then click on it
again and move it to the desired location.
- To combine
two adjacent vertices (thereby eliminating one side of the polygon), click on
the vertex to be eliminated and move it to vertex to which it is to be
combined.
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Change Priority
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when multiple deck polygons are laid down in
the same area, the polygon on top (the last one laid down) takes precedence
over any polygons (or portion) below. In some cases it may be necessary to
change the order, or Priority, of these polygons, moving them up or down. This
can be done using the
Change Priority command. When invoked
it displays a list of all of the deck polygons on that layout type. Selecting a
polygon from that list causes the polygon to be highlighted in plan. The Up and
Down arrows can be used to move that polygon up or down in priority. This
command is useful, for example, if a polygon is completely covered by other
polygons and is no longer necessary; it can be moved up the list and then
deleted.
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Delete - Single
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Click and then select the deck to be deleted.
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Delete - Fence
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Click and the fence an area. All of the decks
within the fenced area will be deleted.
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Show
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Used to display the properties of deck
assignments for a selected deck. To see a list of the polygon vertices, select
the
More>> button.
Tip: Deck assignments are depicted on
the screen by a hatching pattern while in Deck Assign mode. They can also be
displayed by toggling the
Show Decks option of the
command; there is an option to either show
the decks clipped to the slab edge or unclipped to the slab edge.
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Show Same
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Opens the
Show Same Decks dialog,
which lists all of the decks. When one is selected from the list, all
occurrences of that deck type are highlighted in the plan. This provides a
quick way of verifying that the correct decks have been assigned in each
location.
Tip: This provides a quick way of
verifying that the correct decks have been assigned in each location.
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Property Table
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Opens the
Deck/Slab Property Information
dialog, which is used to enter the Composite, NonComposite, or Concrete Floor
System Property Information for all decking/slabs to be used in the current
model.
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