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Technical notesNTC 2018

Steel lift shaft: what is needed for filing with the Italian building authority

A steel shaft in profiles is a structural work: before it goes up it has to be filed. Here's what we prepare and what we need from you.

· Studio Draion

If the lift has no masonry shaft, the shaft is the steel structure carrying guide rails, doors and cladding. In law, it's a structural work.

We calculate it to the NTC 2018 and, before work starts, it has to be filed with the competent office: in Tuscany, the Genio Civile (building authority).

Who does what

The client files it through a qualified professional. The report and structural drawings are signed by an engineer. The lift manufacturer supplies steelwork and loads, but usually has nobody to prepare the structural part: that's what we do.

What we need from you

  • drawings or 3D model of the steelwork, with profiles, thicknesses and connections;
  • the lift loads: guide rail reactions in operation and on safety gear, sling, counterweight, machine room if any;
  • the site: municipality and soil for seismic action, height and exposure for wind and snow if the structure is outdoors;
  • how it's fixed to the building: own foundation, anchors to the floors, intermediate supports.

What's in the report

  1. the work and materials, with steel and bolt grades;
  2. loads: permanent, variable, lift, wind, snow, seismic;
  3. combinations at ultimate and serviceability limit states;
  4. calculation model: static scheme, restraints, connections;
  5. checks on strength and stability of uprights, crossbeams, bracing and connections;
  6. deflection: it matters for a lift, guide rails have their own limits under EN 81-50;
  7. anchors to the building or foundation.

The report goes with structural drawings, materials report and maintenance plan. Forms change from region to region and are handled by whoever files.

What goes wrong

Usually two things. The steelwork is already ordered when someone finds out filing is needed, and the calculation asks for a different profile. Or the loads arrive without the safety gear case, which almost always sizes the uprights.

The fix: call us while the structure is still a drawing.

For shafts designed with Truss the calculation starts from the same data as the drawings. For those drawn by others we start from DXF and 3D.