1. About & Disclaimer

    The web tool calculates frame stability of multi-storey braced frames, in accordance with BS EN 1993-1-1. The calculations are performed for a single vertical bracing system, so it is important that the vertical loads and lateral loads are associated with a single bracing system, not the entire structure.

    All actions should be entered as characteristic values. From the permanent and variable actions and floor area associated with the bracing system specified at each level, the software calculates the EHF. Factors αh and αm are set to 1.0. The characteristic wind load per bracing system is assumed to be uniform over the full height of the bracing system; it is converted to point loads at floor levels in proportion to the storey heights.

    The bracing system is assumed to be a vertical Pratt truss, meaning that the horizontal members (beams) carry axial load. Bracing members may be circular hollow sections or square hollow sections.

    Users are offered the facility to rearrange the storeys, via the arrows on the right hand side of the input screen. If all storeys are deleted, a single storey (ground floor) can be recreated. All sections and geometry can be changed to that of the topmost storey.

    Two cases are verified – with imposed load as the leading variable action and secondly with the wind as the leading variable action.

    Although care has been taken to ensure that the calculated resistances are correct, users should verify the output. The Steel Construction Institute and other parties associated with this software and website assume no responsibilities for errors or misuse of this software, or damage arising from use of this software.

  2. Provide Input

    Specify the arrangement of the bracing system, wind loads and the actions on the roof and floor. In every case, the loads should be those associated with one single bracing system, not the complete building.

  3. Calculate and review Output

    Calculate frame stability and print results.