COLUMNS AND TIES

Columns AND TIES (Compression and tension resistance)

A Column is a member resisting axial compression forces. Column connections are usually in direct end bearing. Studs are columns, as are posts and struts. Length and condition of lateral (sideways) support classify columns as either “long” or “short”. Struts are short columns, resisting loads by pure compression strength.

Long columns are subject to buckling, in which the loaded column can be deflected out of line and fail by a combination of compression and bending. Loads on long columns are governed by what is called the L/d or “slenderness” ratio, i.e. the length of column that is laterally unsupported (L) divided by the least dimension (d) of the column. This ratio should be less than 50. Long column load capacity varies inversely as the square of this ratio, i.e. capacity decreases as the ratio increases. See the Column table for more data.

A tie is the reverse of a column, in that it resists axial tension forces. Temporary bracing is often in tension. Permanent tension members are common in trusses, uncommon elsewhere. Tie connections place shear on connecting hardware.