UNITAR STRUCT / DOCUMENTATION

Beams

v2026-10-11

Straight, inclined and kinked beams, single or continuous. The software finds the supports, the spans and the cantilevers by itself.

Create a beam

Open the Beam menu on the 3D Modeling toolbar or type the command. You need an active level.

Command	Button	What it does
`MODEL_BEAM`	Beam	A beam on the active level, from two points on its axis.
`MODEL_BEAM_INCLINED`	Inclined beam	An inclined beam: two points and the level of each end.
`BEAM_TOP_OFFSET`	Beam top offset	Raises or lowers the top face of the selected beams. Level and reinforcement are kept.
`MODEL_EXTEND_END`	Extend end	Moves one end of the beam, for example to the face of the column.

MODEL_BEAM asks in turn:

Insertion method [Two-points/One-point] <Two-points>: — two points on the axis, or one point and the length.
Beam start point: and Beam end point: — the ends of the axis.
BW [cm] <30>: and H [cm] <60>: — width and depth.
Top face offset vs story top [cm] <0>: — 0 puts the top face at the level. A positive value gives an upstand beam, a negative one a dropped beam.

The two points are the beam axis: the width is placed symmetrically about it and the depth hangs below the top face.

Supports, spans and cantilevers

You do not declare the supports. The software reads them from the model:

A support is a column, a wall or a basement wall that reaches the beam soffit. A wall running along the beam counts as well.
Collinear beams with the same top face form a continuous beam. Reinforcement is edited for the whole chain.
An end that stops on a perpendicular beam at least as deep becomes a secondary-beam support.
A beam with a single support is treated as a cantilever.
Two inclined beams with a common apex, no column under it and supports at both ends are drawn as a kinked beam.

If the reinforcement window shows a single span or a free support although the beam is supported at both ends, check that the element under it is a column or a wall and that it reaches the beam soffit. When the window opens, the command line lists the supports found.

Reinforce

On creation the beam gets starting reinforcement. Change it with REBAR_EDIT (the Edit rebar button, Rebar tab).

Per span: bottom bars (number and diameter), stirrup diameter, spacing at the support and in the field.
Per support: top support bars (number and diameter).
For the whole beam: continuous top bars, inner stirrups and web bars.
Critical zones: the ductility class and the length with closer stirrups are chosen for the whole project in UNITAR_SETTINGS or with BEAM_CRIT. You can change them for one beam in the reinforcement window.
If you change the width or depth in the window, the 3D solid is rebuilt. The length is changed with MODEL_EXTEND_END.

What appears on the sheets

One elevation for each beam or chain, at 1:50, with the supports drawn and hatched.
The sections, at 1:25 or 1:20, next to the elevation. Identical sections are drawn once.
The bar details and the schedule of the plan.
Anchorage of the bars at the ends is measured from the face of the support.
The sheet of a level is called REINF_Beams (ARMA_Grinzi when the drawings are in Romanian) and sits in the reinforcement folder of the project.

Good to know

Curved beams are not covered.
A beam belongs to the level whose top is nearest to its top face.
Beams stacked at different heights are separate elements and do not form a chain.
The message [WARN] BEAM_SPANS appears when the number of spans has changed: reopen REBAR_EDIT and confirm the reinforcement.

What is covered and what is not →

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