Hollowcore Online (App)

Last modified by Fredrik Lagerström on 2023/03/30 08:54


Discontinued 2021-08-31

Introduction to Hollowcore Online

Calculate your flooring requirements and find the best hollowcore supplier for your project.

Based on the load/span requirements of your project, hollowcore online can calculate and suggest suitable slab profiles.

You can then download a dxf file of the selected profile to assist with your design.

Using the map below the calculation tool, you can discover selected members of hollowcore online, helping you to find the right supplier based on your location.

Contact details and a link to our members’ websites can be found by clicking on the map markers.

Link to the application: Hollowcore Online

Graphical user interface (GUI)

  • Top menu bar
  • Main window
  • Span width
  • Load type
  • Capacity-graph
  • Company selector
  • Cross section properties
  • Map

Hollowcore flooring calculation guide

Instructions for use:

1. Enter Span – this is the distance between supports which the hollowcore slab must span.

2. Select Load Type – select the eventual use of your project for a simplified total load the hollowcore slabs will typically be exposed to.

3. Click the “Calculate” button, or alternatively, select (by left clicking) a manufacturer near you using the map, and click the “Calculate” button on the information card.


You will be presented with a drop-down menu to a select supplier that manufactures a slab suitable for your project.

For each manufacturer selected, you’ll see a hollowcore section matched to your requirements. The information provided includes a typical load/span table and properties for the section, such as load capacity and load utilization. You also have the option to cycle through all the manufacturer’s profiles using the “Previous” and “Next” buttons.

You can download a drawing of the slab profile selected by clicking on the button labelled “Dxf”.

Hollowcore producers / Map user guide

A red dot marks your current location, with map marker pins showing hollowcore producing members of hollowcore online.

The map can be moved by left-clicking and dragging, and zoomed in or out using the “+/-“ buttons in the top left.

By clicking on a marker pin, you can bring up a profile card for that member, with the option to visit their website and perform a calculation based on the slab sections they manufacture.

List of producers with calculable profiles

List of other producers that are represented on the map


For these results the maximum number of prestressing wires has been used. There will be a future update when the capacities will be lower, since one wire will be removed from the calculations, meaning that n-1 wires will be used for maximum values.

The calculations are being performed according to EN 1990 formula (6.10b)

1.2 x Gk + 1.5 x qk                          (6.10b)

No extra deadload except the dead load of the element is considered. For calculations with structural topping or screed, consult a calculation that takes that into account (for example StruSoft PRE-Stress)

Imposed live load types according to EN 1991-1-1

CategoryLoad typeValue (qk)
ADomestic and Residential (Floors)2.0 kN/m2
ADomestic and Residential (Stairs)2.0 kN/m2
BOffice Areas Buildings3.0 kN/m2
C1Congregation Areas Buildings (Room with tables)3.0 kN/m2
C2Congregation Areas Buildings (Room with permanent seats)4.0 kN/m2
C3Congregation Areas Buildings (Room for transportation)5.0 kN/m2
C4Congregation Areas Buildings (Room for physical activities)5.0 kN/m2
C5Congregation Areas Buildings (Room for large crowds)5.0 kN/m2
D1Shopping Areas Buildings (Areas for retail stores)4.0 kN/m2
D2Shopping Areas Buildings (Areas for department stores)5.0 kN/m2
E1Storage Areas Buildings7.5 kN/m2
FVehicles (Up to 30kN)2.5 kN/m2
GVehicles (Between 30kN and 160kN)5.0 kN/m2
HRoofs1.0 kN/m2

Designing calculation

If the Shear calculation is governing then ULS_V is shown after the maximum allowed characteristic imposed load value (qk,max).

If the Moment calculation is governing, then ULS_M is shown.


Cross section properties

Shown values are:

  • The span length
  • Characteristic maximum allowed imposed live load
  • Current imposed characteristic live load
  • Utilization

The calculated cross section is available to download as a Autodesk dxf-file (Drawing Exchange Format)

Future development

Development has been stopped and the project has been terminated as of 2021-08-31

The development is paid for by the participating companies. In the list of development ideas are:

  • Calculations should be performed with nmax - 1 wires, since there are curently no room for errors in the design process, or possibility to have any holes that will reduce the capacity.
  • Extra dead load
  • Eigenfrequency-calculations

This list is always considered when doing new development. Contact a company that has their products presented and they will contact StruSoft for your new idea!


The applications makes a preliminary design of the different cross sections with a given imposed load.

The calculation does not take the following parameters into account:

  • Serviceability effects
    • Cracking
    • Deformation
    • Stress limitations
    • Eigenfrequencies
    • Transportation, lifting, and storing the elements
  • Long term effects (Creep, Shrinkage, Relaxation)
  • Fire
  • Curing of the concrete in early stages
  • Torsion
  • Recesses and holes causing reduced capacities

The properties above will be taken into account if a calculation is being performed by PRE-Stress. There are a few parameters that are not taken into account in Hollowcore Online or PRE-Stress:

  • Sound insulation / noise transported in a structure.
  • LCA, Life Cycle analysis. Impact on the environment
  • Cost estimations, as that is up to each supplier to provide for each project tender