Columns

The portal column top and bottom levels, section size, grade and base fixity can be specified in the Columns tab. External and internal parapets can be added by specifying their height and section size.

Tip:- If a step in the frame height is required at a particular column, then the height to the lower rafter should be entered plus the additional height to the higher rafter, for example 5 + 3, which would give an overall height of 8 metres to the higher rafter, with the lower rafter coming in at the 5 metre level.

The portal column base fixity setting here is only applicable if the 'As is' option has been selected in the General input tab.

There is also the option to have a hit and miss columns set up in a multi-span portal, at the valley. First select the 'Removed Columns' button to change the tab as shown below. Enter the column no. on which the hit and miss columns are to run. Then add the bays in which the columns are to be removed. Valley beams will now be added along where the intermediate columns have been removed. These can be set as continuous or simply supported and a section size specified. Often the end bays section size can differ from the main valley section size and this can be specified also.