Three dimensional frame analysis computer programs are being used increasingly as a routine design tool, mainly because of the potential savings in designers labour and the avoidance of numerical errors. In order to realise these savings in practice for portal frames in particular, it is necessary to avoid a number of frustrating traps for the unwary. This paper examines numerical examples of typical single span, two span and 'hit and miss' portal frames in order to identify common problems and solutions.
Robert C. Hairsine, BSc (Hons), CEng, FIStructE, MICE
Consultant structural engineer and software developer, Computer and Design Services Ltd
Consultant structural engineer, Graham Garner and Partners Ltd