Built-up columns shall satisfy the requirements of AISC
Specification Section E6 except as modified in this Section. Transfer of all
internal forces and stresses between elements of the built-up column shall be
through welds.
1. I-Shaped Welded Columns
The elements of built-up I-shaped columns shall conform to
the requirements of the AISC Seismic Provisions. Within a zone extending from
12 in. (300 mm) above the upper beam flange to 12 in. (300 mm) below the lower
beam flange, unless specifically indicated in this Standard, the column webs
and flanges shall be connected using CJP groove welds with a pair of
reinforcing fillet welds. The minimum size of fillet welds shall be the lesser
of 5/16 in. (8 mm) or the thickness of the column web.
2. Boxed Wide-Flange Columns
The wide-flange shape of a boxed wide-flange column shall
conform to the requirements of the AISC Seismic Provisions. The
width-to-thickness ratio (b/t) of plates used as flanges shall not exceed 0.6
SQRT(Es /Fy), where b shall be taken as not less than the clear distance
between plates.
The width-to-thickness ratio (h/tw) of plates used only as
webs shall conform to the provisions of Table I–8–1 of the AISC Seismic
Provisions. Within a zone extending from 12 in. (300 mm) above the upper beam
flange to 12 in. (300 mm) below the lower beam flange, flange and web plates of
boxed wide-flange columns shall be joined by CJP groove welds. Outside this
zone, plate elements shall be continuously connected by fillet or groove welds.
3. Built-up Box Columns
The width-to-thickness ratio (b/t) of plates used as flanges
shall not exceed 0.6#Es /Fy #, where b shall be taken as not less than the
clear distance between web plates.
The width-to-thickness ratio (h/tw) of plates used only as
webs shall conform to the requirements of the AISC Seismic Provisions. Within a
zone extending from 12 in. (300 mm) above the upper beam flange to 12 in. (300
mm) below the lower beam flange, flange and web plates of box columns shall be
joined by CJP groove welds. Outside this zone, box column web and flange plates
shall be continuously connected by fillet welds or groove welds.
4. Flanged Cruciform Columns
The elements of flanged cruciform columns, whether
fabricated from rolled shapes or built up from plates, shall meet the
requirements of the AISC Seismic Provisions.
User Note: For flanged cruciform columns, the provisions of
AISC Specification Section E6 must be considered. Within a zone extending from
12 in. (300 mm) above the upper beam flange to 12 in. (300 mm) below the lower
beam flange, the web of the tee-shaped sections shall be welded to the web of
the continuous I-shaped section with CJP groove welds with a pair of
reinforcing fillet welds.
The
minimum size of fillet welds shall be the lesser of 5/16 in. (300 mm) or the
thickness of the column web. Continuity plates shall conform to the
requirements for wide-flange columns.
