This page specifies the technical details of the first version of the Engineering tool in Scaffcalc.
Considerations
Apart from the stated limitations, all necessary loads and requirements according to EN 12811 are considered, including references to EN 12812 and EN 1993-1-4. The list below provides a simple checklist of considerations included in the first release of the calculation feature.
Loads
Included load cases:
- Self weight of all scaffold components
- Counterweights that are placed in a scaffold on a level with plank(s).
- Imposed load dependent on load class. Applied fully on one level and half on one level. Applied first on the widest decked level, then on the highest.
- Characteristic wind load dependent on user inputs. Increases by height.
- Working wind load, 0.2 kN/m2
- Indoor case: Imposed horizontal load. 3% of the imposed load per bay (min 0.3 kN).
- Inclination load caused by initial inclination of the standards.
Load combinations
A minimum of 12 load combinations is evaluated per scaffold to determine worst-case results. At the end of the calculation, these are summarized as two worst-case load combinations: max compression and max tension, where the maximum of each is extracted per individual component. This is shown in the compression/tension toggle. For deformations, a single worst-case deformation shape is extracted.
Each load combination is iterated by the number of facade directions of the scaffold to simulate wind load / imposed horizontal load in any perpendicular direction on the scaffold.
Wind load combinations
- Overturning / sliding (EQU):
- 0.9 x self weight
- 1.5 x characteristic wind load
- Max pressure, out of service (ULS):
- 1.35 x self weight
- 1.5 x characteristic wind load
- 1.5 x reduced imposed load
- Max pressure, in service (ULS):
- 1.35 x self weight
- 1.5 x working wind load
- 1.5 x full imposed load
No wind load combinations
For load combinations without wind, the horizontal load comes from people working on the scaffold. These are considered if the scaffold is placed indoors, or if the resulting wind load is less than the horizontal load caused by people working on the scaffold.
- Overturning / sliding (EQU):
- 0.9 x self weight
- 1.5 x horizontal working load
- Max pressure, in service (ULS):
- 1.35 x self weight
- 1.5 x horizontal working load
- 1.5 x full imposed load
Note: SLS load combinations are not currently available for analysis. Self weight includes counterweights.
Stiffnesses
To be written.
Stability analysis
A linear buckling analysis (LBA) is performed to determine whether a second-order analysis of the scaffold is required. This analysis is made per load combination. Three possible outcomes of the LBA analysis:
- Stable scaffold. Linear analysis is sufficient.
- Some sway occurs under the vertical load for this load combination. An amplification factor is applied to the horizontal forces in this load combination to account for second-order effects, in accordance with Eurocode. This is a simplified approach to performing an iterative second-order analysis.
- Large sway under the current vertical load: the scaffold is assessed as too unstable.
Limitations
Current limitations of the Engineering feature. All limitations listed below will be addressed in future versions:
- Facade and freestanding structures only. Suspended scaffolds and scaffold types excluded from EN 12811 scope are not supported. This includes platforms suspended by ropes, horizontally movable platforms, power-operated scaffolds, scaffolds used as protection for roof work, and temporary roofs.
- No structural verification or calculation report. All results must be verified against manufacturer documentation.
- 15 min time limit for any scaffold calculation
- Supports Layher scaffolds only (Layher Allround LW)
- Fully linear elastic analysis, meaning:
- No P–Δ effects (second-order effects handled only via the stability analysis / amplification approach described above)
- Connection stiffnesses are constant (independent of force level)
- Ground supports are modeled as fully anchored to the ground (no uplift; tension is reported instead)
- Connection eccentricities are not included
- Base plates are always assumed to be of type Base Plate 60
- Friction coefficient fixed at 0.5 (assumed steel-to-timber type support)
- No reduction of wind in regard to facade opening ratio
- No dynamic loads (static load cases only)
- No specialized imposed-load distribution for birdcage scaffolds (platform load is uniformly distributed per bay; the EN 12811 6 m² note is not considered)
- Stair components do not contribute to structural stability bracing
For more information or questions about the considerations and limitations of the Engineering tool, please reach out to support@scaffcalc.com, and we’ll get back to you as soon as possible.