Frame stability tool available online
A new web-based frame stability tool that evaluates the stability of multi-storey braced frames, in accordance with BS EN 1993-1-1 is now available at: www.steelconstruction.info
The parameter αcr is determined using the combination of the Equivalent Horizontal Forces (EHF) and wind loads on the frame, in conjunction with the vertical loads.
The calculations are performed for a single vertical bracing system, which is assumed to be a vertical Pratt truss.
Beam and column members may be selected from the full range of UKB and UKC sections respectively, and bracing members may be circular or square hollow sections.
Abdul Malik of the Steel Construction Institute said: “The programme requires the user to provide the lateral and vertical loading associated with the bracing system – generally any structure will have two or more bracing systems.
“The single bracing system analysed in the tool will therefore carry only part of the lateral load and part of the vertical load.”
Wind load is assumed to be distributed uniformly over the full height of the bracing and is converted into point loads applied at the nodes. In complex buildings with bracing systems of differing stiffness, it will be necessary to determine the proportion of load carried by each bracing system.