123 — Sandwich Panel

An insulated sandwich panel is two concrete wythes with a layer of rigid insulation between them, tied together by wythe connectors. With the exterior face cast down, the exterior wythe and the insulation go down on the bed first. The structural wythe, with the pick and brace inserts, is the second pour.

The Sandwich Panel button records those layers on the panel. ConstructiVision then takes the insulation out of the panel solid, so the weight, volume and centre of gravity in the title block come from the two concrete wythes. It also draws the wythe connectors and a callout on the sheet.

Where it is

ConstructiVision toolbar → Sandwich Panel (tooltip: Sandwich Panel). It sits right after Edit Main Panel, beside Top Step and Footing Step. The button runs CV-FEAT-SANDWICH.

Open a panel drawing first. The button opens ConstructiVision – Sandwich Panel (Insulated):

field

what it holds

This is an insulated sandwich panel

turns the layers on for this panel

Exterior wythe

thickness of the wythe cast against the bed

Insulation thickness

thickness of the insulation layer

Insulation type

free text, for example XPS

Structural wythe

interior or exterior

Structural thickness

read only: what is left of the panel thickness

Connector action

non-composite, composite or partial

Spacing, horizontal / Spacing, vertical

the connector grid

Edge distance

how far the outer connectors sit from the panel edges

The two groups are labelled Layers (the exterior face is cast down) and Wythe connectors (as the engineer specifies). A line of text under the fields reports what the dialog finds wrong with the layers, or reads The layers check out.

Try it on AAA039

AAA039 is a panel from the Arlington Airport A sample project. It is 28’-0” wide and 7 1/4” thick, and with no layers recorded its title block gives 126.2 KIPS and 31.2 Cu. Yd.

  1. Open AAA039.dwg.

  2. Click Sandwich Panel. The box is clear, Structural thickness reads 7 1/4" (the whole panel), Structural wythe reads interior and Connector action reads non-composite.

  3. Tick This is an insulated sandwich panel.

  4. Exterior wythe 2", Tab. Insulation thickness 2", Tab. Insulation type XPS, Tab.

  5. Leave Structural wythe on interior. Structural thickness now reads 3 1/4".

  6. Set Connector action to composite.

  7. Spacing, horizontal 2'-0", Spacing, vertical 2'-0", Edge distance 6".

  8. Read the line under the fields. On AAA039 it says:

    The exterior wythe is 2"; it must be at least 2 1/2" (2" plus the deepest cut into the
exterior face, 1/2": a form liner or a reveal).

    AAA039 carries 1 1/2” X 1/2” reveals, so a 2” exterior wythe is under the minimum the dialog asks for. This lesson keeps 2” here so you see the check fire; the next section clears it.

    The dialog has room for one row of this line, so on screen it stops at the deepest cut into the. The message in the next step repeats it in full.

  9. Click OK. An AutoCAD Message opens:

    The sandwich panel was saved. Check these before it goes to the engineer:

- The exterior wythe is 2"; it must be at least 2 1/2" (2" plus the deepest cut into the
  exterior face, 1/2": a form liner or a reveal).

    Click OK on the message. The layers are saved and the panel redraws.

What you see

The command line reports the redraw and the layers:

[CV-FEAT] Sandwich Panel accepted -- redrawing panel...
[CV-SANDWICH] insulation 2" taken out of the panel solid (2" above the face cast down): weight and CG are the two wythes. No solid concrete zones are modelled; add any the engineer specifies.
[CV-SANDWICH] 238 wythe connector(s) drawn on layer sandwich_conn (no opening recorded by this draw; standard and rough openings excluded from the panel data).
[CV-SANDWICH] stack callout drawn on layer sandwich.

On the sheet:

  • 238 wythe connectors, drawn as small circles on layer sandwich_conn, on a 2’-0” grid of 14 columns by 17 rows. The outer connectors sit 6” in from the panel edges.

  • A four-line callout on layer sandwich:

    SANDWICH PANEL
2" exterior wythe / 2" XPS insulation / 3 1/4" structural wythe (interior)
Composite connectors @ 2'-0" H x 2'-0" V, 6" from edges
Weight and CG: concrete wythes only -- no solid concrete zones modelled

  • The title block now gives WEIGHT 102.0 KIPS and VOLUME 25.2 Cu. Yd., down from 126.2 and 31.2. The 6.0 Cu. Yd. that left the panel is the 2” of insulation over the whole 28’-0” x 34’-6 1/2” face.

Openings stay clear of the connectors. On SegalP15041, which has two openings, the same layers gave:

[CV-SANDWICH] 304 wythe connector(s) drawn on layer sandwich_conn, clear of 2 drawn opening(s).

The sandwich wythe belongs to the 3 Down Face phase: that phase button’s tooltip lists it (phase views are lesson 119).

The two checks the dialog makes

Reopen Sandwich Panel on the same panel. The line under the fields updates when you Tab out of a field.

  1. Exterior wythe thickness. Type 3" in Exterior wythe and Tab. Structural thickness reads 2 1/4" and the line reads The layers check out.

  2. Pour order. Now set Structural wythe to exterior. The line reads:

    The structural wythe is the exterior one, but with the exterior face cast down it is poured
first, on the bed. The pick and brace inserts are cast in the second pour (the up face), so
they would anchor in the interior wythe. Cast the other face down, or record the interior
wythe as structural.

    On screen only the first row shows, up to it is poured. The rest is the reason and what to do about it.

  3. Click Cancel. The command line reads [CV-FEAT] Sandwich Panel cancelled -- nothing changed. and the stored layers are as you left them in step 9.

These checks compare thicknesses and the pour order. They do not check structural capacity, and the dialog does not choose or size connectors: it records the action and spacing as the engineer specifies, and the saved message says to check the layers before the panel goes to the engineer.

Turning it off

Open Sandwich Panel, clear This is an insulated sandwich panel and click OK. The panel redraws without the callout and without the connectors (layer sandwich holds no text and layer sandwich_conn is gone), and the title block goes back to the solid panel’s weight.

What this lesson does not cover

  • Callouts on a crowded sheet. On a dense sheet the callout can land on other text. The command line then says so (1 face or sandwich callout(s) overlap other text …) and leaves it in place. Known open defect CV-3318.

  • Panels drawn before this button existed. A legacy panel whose insulation is only written as a note on the sheet has no layers recorded, and it is weighed as solid concrete. Known open defect CV-3370.

  • Metric. This lesson was run in imperial units only.

Watch the lesson

The video follows Try it on AAA039 and The two checks the dialog makes on a plain copy of AAA039. It does not cover turning the layers off.