Tutorial 30: Blockouts Beyond the Rectangle

An opening goes through the panel. A blockout does not — it is a void or a recess formed into the concrete, and what it is for decides how deep it goes, how it is reinforced around, and whether anything structural lands in it.

Lesson 6 covered the standard rectangular opening. This one covers the blockouts that are not rectangles and not through-holes — four entries from the Tilt-Up Concrete Association panel feature catalog:

Feature

What it is

Standard

Non-rectangular blockout

A blockout with a non-rectangular shape

Field practice

Beam pocket

A surface blockout that receives a structural beam

TCA

Insulation block

A blockout offset from the surface forming the insulation cavity of a sandwich panel

ACI 551.2R

Form liner / exposed aggregate

An architectural finish applied to a recess

TCA

All four are built today

Non-rectangular blockouts, beam pockets, the surface offset an insulation block needs and the form-liner / exposed-aggregate finish are all modeled by ConstructiVision now — they are columns on one row of the Recess and Blockout Details dialog. A beam pocket is not a separate control: it is a recess with a Z Offset of 0, which places the void on the surface rather than burying it in the section. What is still missing is narrower than the feature itself — there is no separate bearing-length field, and the materials list reports a pocket as a generic void. Step 3 says where that bites.

Note

This lesson also exists in the browser. Work it in ConstructiVision on the web — same steps, same values, so you can follow either and end up with the same panel.

What you will build

  • a non-rectangular blockout in a panel face, dimensioned;

  • an understanding of the difference between a through-void and a recess;

  • a beam pocket — the same row with Z Offset left at 0, which opens the void to the face so a beam can sit in it;

  • why an insulation block is a blockout that is offset from the surface rather than cut into it.

Before you start

Watch the lesson

Warning

What this recording does and does not demonstrate. It works rows 1 to 3 of the dialog on TP08-12: a Circle with a 1’-6” radius and a 2” depth, a beam pocket 1’-4” by 1’-0” and 4” deep with Z Offset 0, and an insulation block 3’-0” by 4’-0”, 3” deep at a Z Offset of 2”. It unticks Full on each row before typing the Thickness, and ticks Liner Aggr L on row 1. It does not demonstrate the Arch or Triangle shapes, Snap To, Panel Edge, Inside or No Dim: those are described, and left at their defaults.

The drawing at the end shows all three blockouts, but neither the liner tick nor the block’s 2” Z Offset appears on it; see Steps 4 and 5.

The recording’s own gate requires the blockouts to be drawn on the panel, but it does not check where they are.

Lesson

Step 1 — Recess versus opening

Run CV-FEAT-RECESS. The distinction that matters before you type anything:

Goes through the panel?

Dimensioned to

Opening

yes

both faces; it is a hole

Recess / blockout

no

one face, plus a depth

A recess has a depth because concrete remains behind it. That single value is what the form crew uses to size the block, and it is what tells the engineer how much section is left.

Step 2 — Place a non-rectangular blockout

Recess and Blockout Details is a grid: six rows to a page, five pages — thirty recesses. Enable row 1 and work across it. Two columns are the ones this lesson is about:

  • Shape — a droplist, defaulting to Rectangle. This is where a blockout stops being a rectangle.

  • Radius — the corner or edge radius, which is what turns a rectangle into a rounded or circular void.

The rest of the row is the geometry you already know from openings: Snap To and Measure fix what it is measured from, then Distance, Elevation, Width, Height and Thickness. The panel redraws with the void formed and dimensioned to the panel datum.

Under Thickness each row has a Full box, and it starts ticked: a full-depth blockout that cuts clean through the panel, with Thickness greyed out. Every row in this lesson leaves concrete behind it, so untick Full first, then type the Thickness.

Non-rectangular blockouts are common and unglamorous: a notch around a column, a clipped corner where a duct passes, a cut to clear a footing step. They are field practice rather than a specified standard, which is exactly why they need dimensioning — there is no convention to fall back on.

Step 3 — Beam pocket

A beam pocket is a recess that a structural beam sits in. It differs from an ordinary blockout in three ways, and a tool that treats it as a plain rectangle gets all three wrong:

  1. It carries load. The concrete under the pocket is a bearing surface, so its depth is a structural dimension rather than a cosmetic one.

  2. It has a bearing length. How far the beam sits into the panel is called out separately from the pocket’s overall size.

  3. It is reinforced around. The bars near a pocket are placed to suit it.

There is no Beam Pocket button, and there does not need to be. A pocket is a row of the dialog you have just used with one column doing the work — Z Offset, left at 0. The manual is explicit: “a value of zero (0) will place the block out on the surface for Beam Pockets, or architectural features.” A Z Offset of 0 leaves the void open to the face instead of burying it in the section, and a void open to the face is what a beam can be set into.

On a free row:

  • Enable the row, and leave Shape on Rectangle.

  • Distance and Elevation — where the beam lands: across from the panel side, and up from finished floor. Use the Snap To boxes only if the beam genuinely sits hard against an edge.

  • Width and Height — the size of the pocket opening, the beam plus its construction tolerance.

  • Thickness — untick Full under it, then type the pocket depth, how far into the panel it goes. This must not be 0. A Thickness of 0 cuts clean through the panel and greys out On Face and Z Offset, which is the tell that you have made an opening rather than a pocket.

  • On Face — U or D, the face the beam arrives at. Which of those is “the outside” depends on Tutorial 28: Casting Orientation & Yard Layout.

  • Z Offset — 0. That is the pocket.

Confirm with OK. The panel redraws with the pocket formed on the face and dimensioned to the panel datum, carrying its depth — the value the form crew builds the block to, and the value that tells the engineer how much section is left behind the bearing. Step 4 uses the same column at the other extreme.

Two things the pocket does not get, and both are worth knowing before you rely on the output:

  • There is no separate bearing-length field. How far the beam sits into the panel is the pocket’s Width or its Height, depending on which way the beam runs, so the number is recorded — but it is recorded as an opening size, not called out as a bearing dimension in its own right. If the bearing length is the figure the erector has to hit, say so on the drawing as well.

  • The materials list reports it as a generic void. The pocket is drawn and dimensioned, and the quantities come off it, but nothing in the list distinguishes it from any other blockout of the same size. A fabricator reading the panel book sees the pocket on the elevation; they do not see it flagged in the schedule as something that carries a beam.

Step 4 — Insulation block, and the Z Offset

An insulated sandwich panel is two concrete wythes with insulation between them. The insulation cavity is formed by a block that is offset from the surface — it does not break either face.

That offset is the Z Offset column. Set it and the recess sits inside the concrete rather than being cut into a face: Thickness (with Full unticked) gives the cavity depth, Z Offset gives how far below the surface it starts, and the concrete left in front of it is the outer wythe.

Tip

Z Offset is the difference between a recess and a void. A recess with Z Offset 0 is open to the face — someone can put a hand in it. A recess with a Z Offset is buried, and the only evidence it exists is the drawing. Get it wrong and nobody finds out until the panel is weighed.

Warning

The drawing does not show the Z Offset yet. The value is recorded with the recess, but a buried block is labelled and hatched exactly like a recess open to the face: the block in the video reads 3” Deep Recess Dn. A crew reading that sheet would form an open recess. Until the drawing carries it, write the offset on the drawing yourself.

The panel-level piece still missing is derivation: the two wythe thicknesses are typed rather than computed from the cavity, so they can disagree with it. Enter all three and check them against each other.

Step 5 — Form liner and exposed aggregate

A form liner is a textured sheet fixed to the casting bed so the concrete picks up its pattern. Exposed aggregate is a surface treatment achieved by washing back the paste. Both are applied to an area of the panel, not to a shape cut from it.

Both are on the row: the Liner Aggr column, L for liner and A for exposed aggregate. Setting it marks that recess as receiving a finish treatment rather than being a plain void.

The finish is recorded per recess, in the panel’s own data. It is not yet shown on the drawing, and it is not reported as an area in the materials list, which is how liner is bought and how the finish is priced. So for now, mark it on the drawing yourself and take the areas off separately when pricing.

Step 6 — The rest of the row

Three more columns decide where the recess lands, and they work the same way as the feature-strip row in Tutorial 29: Feature Strips & Reveals:

  • On Face — U or D, which face in the casting bed. As always, which face is “the outside” depends on Tutorial 28: Casting Orientation & Yard Layout.

  • Panel Edge — L or R, for a recess at a panel edge.

  • Inside and No Dim — whether the recess is dimensioned. As with reveals, use No Dim sparingly: an undimensioned blockout is one the form crew has to scale.

Recorded, not certified

ConstructiVision records the pocket depths, blockout sizes and cavity dimensions you enter and carries them consistently to the drawing, the schedules and the materials list. It does not check them against a structural design. Sizing a beam pocket is the engineer’s decision.

Check your result

  • You can state the difference between an opening and a recess, and name the value a recess has that an opening does not.

  • You have placed a non-rectangular blockout using Shape and Radius, and can point at its dimensions.

  • You have placed a beam pocket — a recess with a Thickness and a Z Offset of 0 — and can say why the Z Offset is the column that makes it one.

  • You can say what a Z Offset other than 0 does, and why a recess with one is invisible on the finished panel.

  • You can find the Liner Aggr column and say what L and A mean.

  • You can say why a beam pocket is not just a rectangular recess, and name the two things about it you still have to put on the drawing yourself.

Where next