New generation of rollformers form the trapezoidal profile and bend the sheet to the radius wanted in one step.
Every individual arch is produced exactly for the separate roof project, so proverbially never-ending number of variations are possible.
Ultimate spans of the profiles are dependent on the radius:
| Profile type |
Minimum radius(m) |
Max. span single-skin arch |
Max. span double-skin arch |
| Legato 40 |
4,00 |
10,50 |
14,25 |
| Legato 70 |
8,00 |
16,50 |
20,00 |
| Legato 107 |
10,00 |
20,00 |
23,00 |
| Conditions: snow load 0,75 kN/m˛; closed building, eaves height of buidling: max. 6 m above ground |
The following parameters are limiting values regarding the producibility:
Production:
Due to geometrical possibilities of the bending machine, the radius should not be smaller than 85 % of the arch length (e.g. arch length of 20 m, min. radius of 17 m).
Transport:
As the LEGATO arch is transported to the building site in one piece a maximum arch rise of 2.8 m should be taken into consideration.
Static:
Decreasing arch rise is accompanied by increasing horizontal supporting reaction on the substructure. From a static point of view a radius/span ratio of 1:1 is favourable yet lager radii may be chosen as well. |
