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Structural Engineering Software


Portal Frame Builder

Create a complete 3D portal frame model in minutes

The SPACE GASS portal frame builder lets you quickly generate a portal frame model, complete with dead loads, live loads, wind loads, load combinations and full steel member and connection design data.

  • Fully integrated into SPACE GASS.
  • Generation of the complete geometry.
  • Dead loads, live loads and wind loads calculated.
  • Steel member and connection design data generated.
  • Combination load cases created for multiple wind directions.
  • Building orientation taken into account.
  • Terrain category averaging.
  • Topographic and shielding multipliers.
  • Internal pressure coefficients to allow for openings.
  • Gable or monoslope roofs.
  • Symmetric or asymmetric roofs.
  • Equal or unequal bays.
  • Side and end overhangs.
  • Knee and ridge haunches.
  • Knee and ridge braces.
  • Roof and wall bracing.
  • End and internal frame props.
  • Sheeted or rigid panel walls.
  • Smooth, corrugated or ribbed sheeting.
  • Fly braces.
  • Flange restraints.
  • Gridlines and dimensions.
  • Fully compliant with AS/NZS1170.2 and IS875.

Creating a portal frame model can be as simple as choosing its basic geometry, typing in its dimensions, nominating its geographic location and orientation, selecting a terrain category and clicking Ok. Of course you also have full control over things like overhangs, props, bracing, haunches, section sizes, supports, sheeting, wall rigid panels, dead and live loads, design life, terrain category averaging, shielding effects, topographic effects, internal pressure coefficients (for simulating openings), combination load cases for multiple wind directions, steel member design data and steel connection design data.

Once generated, you can further modify or add to the model by using the normal SPACE GASS input and editing techniques. Alternatively, you can go back into the portal frame builder, make changes and then click Ok to have the model re-generated. All of the portal frame data is remembered and saved with the job, and so even if you re-open the job weeks later, you can still open the portal frame builder to view or edit any of its parameters.


Choose the building configuration and then type in the basic dimensions.

Bay Spacing, Props and Bracing

The bays are equally spaced by default, however you can make them unequal if required. Side wall and transverse roof bracing can be generated by just ticking boxes for the desired bays.

Similarly, end wall and longitudinal roof bracing can be generated by ticking the appropriate boxes. Props can be specified for internal and end frames, and can be positioned at any locations or generated automatically if they are equally spaced.


The knees and ridge can be strengthened by haunches or braces. Haunches and braces can be different on the left and right, and can be different for the end frames compared to the internal frames.


Specify your section properties for the various components of the building.

Purlins and Girts

Even though purlins and girts are not actually generated in the model, their positions and sizes affect the geometry of the building and the flange restraints and fly braces for the columns and rafters.

Sheeting and Rigid Wall Panels

Frictional wind loads depend on the type and orientation of the sheeting. For buildings with rigid panel walls the wind loads are transferred direct to the eave ties and end frame rafters rather than to the columns.

Dead and Live Loads

Permanent and superimposed dead loads are applied to the actual area of the roof, while live loads are applied to the projected plan area.

You can have the live loads calculated automatically if you tick the "Calculate" box.

Wind Loads

All the wind calculations are done for you based on the geographic location, the orientation of the building, the minimum design life and the various terrain, shielding and topographic parameters.

The terrain category, shielding, topographic and internal pressure coefficients can be set the same for all wind directions or you can specify different values for each building axis.


If your terrain category changes as you approach the building then terrain category averaging is done in accordance with the selected wind code.


The shielding multiplier can be specified directly or calculated for you based on the size and position of other buildings in the vicinity.


The topographic multiplier can be specified directly or calculated for you based on the height of the terrain and the size and position of nearby hills, ridges or escarpments.


Openings in your building can be simulated by the use of internal pressure coefficients that you can specify differently for each wind direction.

Calculation Panel

In order to get a quick snapshot of the wind calculations you can click the "View Wind Calculations" button to display a panel containing the key wind calculation values.

Load Combinations

The portal frame builder creates numerous combination load cases for the ultimate and serviceability limit states that combine dead, live and wind loads, taking into account all wind directions.

The Finished Product

When you're finished, just click Ok to see your portal frame generated and beautifully rendered in the main SPACE GASS window, ready for analysis and design.

Try it for Free!

Even if you haven't purchased the portal frame builder module for SPACE GASS, you can still try it for free by just clicking the portal frame builder button in your copy of SPACE GASS.

If your SPACE GASS is older than v12.51.500 then it contains an older version of the portal frame builder that doesn't have all of the capabilities mentioned above. To see the new version you should ugrade your SPACE GASS.