Building Core#

This command places a so-called Building Core in your project. When analysing a system, this family is interpreted as a Design Element by SOFiSTiK and allows the integration of area results for multiple walls into a line result.

../../_images/grp_utilities_designelements.png

See also

Please refer to the Manual of module DECREATOR for more information about Design Elements in general.

Revit Family Building Core#

Building Cores are instances of a specific Revit family called SOFiSTiK_DesignElement_BuildingCore provided by SOFiSTiK. See Family Content for more info.

They are represented by an oriented vertical axis which associates a selection of analytical panels of structural role Wall. Along this axis, the Finite Element forces of the panels are integrated by SOFiSTiK. These integrated forces can be displayed directly in Revit using Show Results or used as input for further design tasks in ssd_small SOFiSTiK Structural Desktop (SSD).

Note

Not all panels from the building core’s selection are equivalent.

Amongst the selection, the panels hosted at the level of the Section Elevation serve as reference. At this level the panels are analysed and this defines the general layout of the core and, if the corresponding property is active, determine its cross section.

The axis of the building core is generated at its center of gravity. It is vertical and covers the complete height of the selection. For the sake of simplification, openings in the walls do not influence the position of the axis. However, openings, when included in Revit’s analytical model, are accounted for in SOFiSTiK’s Finite Element models as well as in the forces calculated and integrated from it.

When panels from the selection are modified, the building core’s axis is automatically updated.

Properties and Parameters#

The SOFiSTiK Structural Properties allow to manage properties assigned to a building core instance.

Especially the user can:

  • adjust the building core’s name

  • highlight the walls associated to the core

  • edit the selection of walls associated to the core

  • active/deactivate the generation of a cross section for the core

  • Adjust the elevation where the wall selection’s layout defines the cross section

Additionally, specific Revit Shared Parameters are assigned to building cores.

  • parameter SOFiSTiK_Category will show the (read-only) value Design Element

  • parameter SOFiSTiK_Type will show the (read-only) value Building Core

  • parameter SOFiSTiK_DesignElement_Name displays the core name as provided in the SOFiSTiK Structural Properties

These shared parameters can, for example, be added to schedules or used to define view filters.

Cross Sections#

If the SOFiSTiK Structural Properties: Cross Section is active, a suitable cross section is generated and mapped to the building core. This section is required to conduct a capacity check of the building core in ssd_small SOFiSTiK Structural Desktop (SSD).

A building core cross section inherits the geometry, layout and properties of the walls placed at the Section Elevation. It has the same local coordinate system as the building core itself. The cross section can be visualised and adjusted in the Polygonal Section Dialog.

Reinforced concrete panels generate a reinforced concrete cross section for the building core. In this case, the cross section generated is automatically assigned a reinforcing steel.

Typical cross section layout and reinforcement placements for a building core

Typical cross section layout and reinforcement placements for a building core (click to enlarge)#

Note

Automatically generated reinforcement placements for building cores are of the following two types:

  • Base reinforcement, labeled B###, in Layer 0

    Placements in the center of each wall-part of the core, one placement on each side.

  • Edge reinforcements, labeled E###, in Layer 1

    Placements at edges of each wall-part of the core, e.g., corners or free ends of the core geometry: two placements for each connected wall-part.

The three digit numbering scheme ### consists of two parts nnm with

nn

increasing number for wall or edge

m

increasing number for reinforcement placements

Hint

With SOFiSTiK Analysis + Design for Revit 2024 Service Pack 1, a warning was added for the reinforcement of polygonal cross sections when the area of equivalent hollow section cannot be calculated correctly.

For SOFiSTiK Analysis + Design for Revit 2024 Service Pack 0 and older, all reinforcements were set to torsional contribution = fully, causing the algorithm to not correctly identify the area of equivalent hollow section. For SOFiSTiK Analysis + Design for Revit 2024 Service Pack 1 and above, this value is set to torsional contribution = partially.

If this warning occurs for existing cross sections, please check the program resultviewer_small SOFiSTiK Result Viewer and adjust the reinforcement in Polygonal Section Dialog by deliberately defining the torsional contribution. See AQUA manual for more information.

Results#

When available in the SOFiSTiK *.cdb, Show Results displays analysis results for the building cores. Therefore, it is possible to visualise in Revit forces and bending moments, integrated over all panels associated to the building core.

Working with Building Cores#

To display integrated analysis results#

The most simple use of Building Cores is the integration of forces from several panels along an axis. The following explanation describes how to achieve this step-by-step.

  1. Modelling

    • Click on Building Core and select the analytical panels of structural role Wall for which you would like have integrated results

    • Validate your selection by clicking on Finish

    • In the dialog, assign a name to your building core

    • In the dialog, deactivate the option Set all walls belonging to this core as shear walls (it is not necessary for this workflow)

    • Validate the dialog with OK, the building core family is loaded in the project and an instance is placed in the model

  2. Analysis

    • Analyse a system from a view where the building core is visible. Automatically, results for the building core are generated in the SOFiSTiK CDB

  3. Evaluation of the results in Revit

    • In Revit, make sure to be in a view where the building core is visible

    • Click on Show Results

    • Select as Data Source a system with the building core

    • Use the group Building Core of the side panel to access analysis results for the core

Together with SSD for advanced analyses and designs#

Building Cores are at the centre of a seismic analysis and shear wall workflow together with ssd_small SOFiSTiK Structural Desktop (SSD). This workflow is described exhaustively in our tutorial Seismic Analysis and Shear Design (BIM Workflow).

The following explanation provides a brief overview of the steps necessary for this workflow.

  1. Modelling

    • Click on Building Core and select the analytical panels of structural role Wall which you would like to design as a core

    • Validate your selection by clicking on Finish

    • In the dialog, assign a name to your building core

    • In the dialog, the option Set all walls belonging to this core as shear walls is necessary to conduct a Shear Design of the walls in SSD

    • Validate the dialog with OK, the building core family in loaded in the project and an instance is placed in the model

    • Additionally, all walls associated to the core now have their property Design Element set to Shear Wall

  2. Analysis

    • Analyse a system from a view where the building core is visible. Automatically, Design Elements are generated in the SOFiSTiK CDB.

    • One main Design Element is generated for the building core itself

    • Each panel associated to the core is set as a Shear Wall. So for each, a member Design Element is also generated

  3. Shear Walls design and Building Core capacity check in ssd_small SOFiSTiK Structural Desktop (SSD)

  4. Evaluation of the results in Revit

    • After completing the designs in ssd_small SOFiSTiK Structural Desktop (SSD) switch back to Revit

    • Make sure to be in a view where the building core is visible

    • Click on Show Results

    • Select as Data Source the system where you conducted the designs

    • Use the group Building Core of the side panel to access analysis results for the core

Hint

Each building core consists of a specific Design Element and the collection of the individual shear walls defining its cross section. Secondary Groups for the elements involved are automatically created and available for post-processing in ssd_small SOFiSTiK Structural Desktop (SSD).

Group ID

Group Title

Description

‘CO##’

Name of Building Core(1) - Core

Building Core Design Element as well as QUAD Finite Elements of associated wall panels

‘CW##’

Name of Building Core(1) - Walls

Shear wall Design Elements as well as QUAD Finite Elements of associated wall panels

(1) Name of Building Core is the name defined during modelling (also name of corresponding cross section)

Graphic - Compare results for secondary groups CO and CW

Graphic - Compare results for secondary groups CO and CW (click to enlarge)#