Graitec PowerPack – Reinforce and Design Multispan Beams in Revit


As a very common assumption for numeric models made In Revit, multispan beams are modelized as a series of colinear individual beams.

Thus, it’s make it easier for users to produce the formwork drawings, especially when placing beam tags which could include a mark number. This mark number (visible on the identity data in Revit Properties windows) could be set as unique per element, depending the codification rules of the project. It is possible to place the same value for several objects but in this case, the number indicated in the tag will be the same for all objects containing the same mark number.

Figure 1 – Mark Number filled in Revit

In addition, for quantity take off, bill of materials trough Revit schedules, it is more practical and accurate to create several single beams for each span in Revit, rather than one single very long beam.

Figure 2 – Example of multispan beams, with two different mark numbers.

Graitec PowerPack propose through the Main bars command, a powerful wizard dedicated to reinforce structural elements such as columns, footing, walls or beams. This wizard proposes advance settings to define directly a full and complete 3D rebar cage instead of placing the bars one per one.

Figure 3 – Main bars command interface applied to beam.
Figure 4 – Example of reinforced beams generated with Main bars command

Nevertheless, to be reinforced as multispan beams, colinear beams should be consider as one, especially for the connection between to beams if we want to generate the appropriate reinforcement including a good management of the area connecting the two beams.

So, at this stage, users are often dealing with a dilemma between having on one hand a right formwork model composed of individual beams (enabling a good numbering identification for tags and good formwork quantities) and the other hand, having a long single beam for all the spans (which will be closer better to prepare the reinforcement part and not practical for the formwork model management).

To satisfy all requirements for having a good formwork model and a good model, compliancy with our tools to generate the appropriate rebar cage, Graitec PowerPack propose a specific command named MultiSpan Beam.

Figure 5 – MultiSpan Beam command

This command will create a specific shared parameter (named “G.Beam Continuity Group”) to all individual beams supposed to be part of the same multispan serie.

It will assign the same value for this shared parameter so that the Main bar command (dedicated to create the rebar cage) will understand that this group of beams as to be consider as one multispan beam. Users just have to launch the command and select the beam belonging to the same multispan serie.

Figure 6 – MultiSpan Beam name in Revit properties

Once the selection of beam is done and validated, we can see in the dialog box all the beams which are going to be group in a reinforcement point of view. The Mark Number is indicated as well, and it is still possible to adjust the selection by removing elements or adding new ones.

Figure 7 – Multispan Beam definition

With this command, users could keep continue to model beams as individual beams and then, will be able to use our Main Bar command as a 3D rebar cage generator. The reinforcement of a selection of beams will be then consider as multispan. Main Bar will automatically detect the spans and users could switch to one span to another one, to define the reinforcement for each span individually.

Figure 8 – Main bar command launch on a multispan beam

With this command, the right reinforcement will be then generated for the extremities of the span and for each connections of the intermediate beams composing the span.

Figure 9 –Multispan beam reinforced with Main bars command

This notion could be also use for Graitec structural Design engine embedded in Revit, centralized in the ribbon PowerPack Design. The purpose of those tools is to launch design directly in Revit.

Figure 10 – Geometry command from PowerPack Design tab

The command Geometryopen a dialog bow where each span corresponding to each individual beam are visible and recognized correctly by the software. Here, users could change section and control the geometry of each span without affecting and modifying the whole span. Thanks to this, after selecting just one beam and using the Calculate command from the PowerPack Design tab, the software will calculate the complete multispan beam with the adapted reinforcement assumptions and generate the full rebar cage.

Figure 7 – Reinforcement for multispan beam, generated by design input and calculate command from PowerPack Design tab

Multispan Beam is a very practical command, easy to implement in your current workflow and which will really speed up the 3D rebar cage reinforcement generation based on your custom formwork model.

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